:root {
  --color-bg: #f5f7f7;
  --color-surface: #ffffff;
  --color-panel: #eef4f2;
  --color-panel-strong: #e4ece9;
  --color-text: #17211d;
  --color-muted: #66736f;
  --color-soft: #89948f;
  --color-border: #d9e1de;
  --color-border-strong: #b9c6c1;
  --color-primary: #1f756a;
  --color-primary-hover: #185d54;
  --color-primary-soft: #dcefeb;
  --color-blue: #315fbd;
  --color-blue-soft: #e3ebfb;
  --color-amber: #a8641b;
  --color-amber-soft: #f6ead8;
  --color-success: #23754a;
  --color-success-soft: #ddf1e7;
  --color-error: #b33939;
  --color-error-soft: #f7e1e1;
  --radius: 8px;
  --radius-sm: 6px;
  --shadow: 0 16px 42px rgba(34, 49, 45, 0.08);
  --shadow-soft: 0 8px 22px rgba(34, 49, 45, 0.06);
  --font-sans: Inter, ui-sans-serif, system-ui, -apple-system, BlinkMacSystemFont, "Segoe UI", "PingFang SC", "Hiragino Sans GB", "Microsoft YaHei", sans-serif;
  --font-mono: "SFMono-Regular", Consolas, "Liberation Mono", Menlo, monospace;
}

.dark-theme,
body.dark-theme {
  --color-bg: #101414;
  --color-surface: #171d1c;
  --color-panel: #1e2725;
  --color-panel-strong: #263330;
  --color-text: #edf3f1;
  --color-muted: #a5b0ac;
  --color-soft: #788581;
  --color-border: #2c3835;
  --color-border-strong: #465651;
  --color-primary: #56b3a6;
  --color-primary-hover: #75c8be;
  --color-primary-soft: #1d3a36;
  --color-blue: #8faef4;
  --color-blue-soft: #1d2d50;
  --color-amber: #e7ad61;
  --color-amber-soft: #3e2f1d;
  --color-success: #7ad39e;
  --color-success-soft: #1d3b2d;
  --color-error: #ef8f8f;
  --color-error-soft: #422223;
  --shadow: 0 18px 48px rgba(0, 0, 0, 0.28);
  --shadow-soft: 0 10px 28px rgba(0, 0, 0, 0.22);
}

* {
  box-sizing: border-box;
}

.hidden {
  display: none !important;
}

html {
  -webkit-font-smoothing: antialiased;
  -moz-osx-font-smoothing: grayscale;
}

body {
  margin: 0;
  min-height: 100vh;
  background: var(--color-bg);
  color: var(--color-text);
  font-family: var(--font-sans);
  font-size: 16px;
  line-height: 1.55;
}

.app-body,
.auth-body {
  overflow-x: hidden;
}

a {
  color: inherit;
  text-decoration: none;
}

button,
input,
textarea,
select {
  font: inherit;
}

button {
  appearance: none;
}

button:focus-visible,
a:focus-visible,
input:focus-visible,
textarea:focus-visible,
select:focus-visible {
  outline: 3px solid rgba(31, 117, 106, 0.26);
  outline-offset: 2px;
}

h1,
h2,
h3,
h4,
p {
  margin: 0;
}

.section-kicker,
.eyebrow {
  display: inline-flex;
  align-items: center;
  color: var(--color-primary);
  font-size: 13px;
  font-weight: 700;
  line-height: 1.2;
  margin-bottom: 10px;
}

.empty-state-container {
  min-height: 180px;
  display: grid;
  place-items: center;
}

.empty-state {
  color: var(--color-muted);
  font-size: 14px;
}

.tab-transition-enter {
  transition: opacity 180ms ease, transform 180ms ease;
}

.tab-transition-enter-start {
  opacity: 0;
  transform: translateY(8px);
}

/* Auth */
.auth-body {
  background: var(--color-bg);
}

.auth-shell {
  min-height: 100vh;
  width: min(1080px, calc(100% - 40px));
  margin: 0 auto;
  padding: 28px 0;
  display: grid;
  grid-template-rows: auto 1fr;
  gap: 28px;
}

.auth-brand {
  display: inline-flex;
  align-items: center;
  gap: 10px;
  width: fit-content;
  color: var(--color-text);
  font-weight: 800;
}

.auth-layout {
  width: 100%;
  align-self: center;
  display: grid;
  grid-template-columns: minmax(0, 1fr) minmax(360px, 430px);
  gap: 20px;
  align-items: stretch;
}

.auth-panel {
  min-height: 480px;
  border: 1px solid var(--color-border);
  border-radius: var(--radius);
  background: var(--color-panel);
  padding: 36px;
  display: flex;
  flex-direction: column;
  justify-content: flex-end;
  box-shadow: var(--shadow-soft);
}

.auth-panel h2 {
  max-width: 420px;
  font-size: 34px;
  line-height: 1.18;
  font-weight: 850;
  margin-bottom: 14px;
}

.auth-panel p {
  max-width: 460px;
  color: var(--color-muted);
}

.auth-card {
  border: 1px solid var(--color-border);
  border-radius: var(--radius);
  background: var(--color-surface);
  padding: 34px;
  box-shadow: var(--shadow);
}

.auth-header {
  margin-bottom: 26px;
}

.auth-header h1 {
  font-size: 30px;
  line-height: 1.2;
  font-weight: 850;
  margin-bottom: 8px;
}

.auth-header p,
.auth-footer {
  color: var(--color-muted);
  font-size: 14px;
}

.auth-form {
  display: grid;
  gap: 16px;
}

.auth-label,
.field label {
  color: var(--color-text);
  font-size: 14px;
  font-weight: 700;
}

.auth-error {
  display: flex;
  gap: 10px;
  align-items: flex-start;
  border: 1px solid rgba(179, 57, 57, 0.28);
  border-radius: var(--radius);
  background: var(--color-error-soft);
  color: var(--color-error);
  padding: 12px 14px;
  font-size: 14px;
}

.auth-btn {
  width: 100%;
  margin-top: 6px;
}

.auth-footer {
  margin-top: 22px;
  text-align: center;
}

.auth-footer a {
  color: var(--color-primary);
  font-weight: 800;
}

/* Shell */
.app-body {
  background: var(--color-bg);
}

.shell {
  width: min(1180px, calc(100% - 32px));
  margin: 0 auto;
}

.shell-header {
  position: sticky;
  top: 0;
  z-index: 70;
  display: flex;
  align-items: center;
  justify-content: space-between;
  gap: 20px;
  min-height: 72px;
  padding: 14px 0;
  background: rgba(245, 247, 247, 0.9);
  border-bottom: 1px solid var(--color-border);
  backdrop-filter: blur(16px);
}

.dark-theme .shell-header {
  background: rgba(16, 20, 20, 0.9);
}

.shell-brand,
.shell-header-right,
.shell-user-badge,
.home-course-actions,
.submission-controls,
.lesson-video-header,
.lesson-material-head,
.exercise-list-header,
.feedback-header {
  display: flex;
  align-items: center;
}

.shell-brand {
  gap: 10px;
  min-width: 0;
  color: var(--color-text);
}

.shell-brand-mark,
.ld-preview-logo {
  display: inline-flex;
  align-items: center;
  justify-content: center;
  width: 32px;
  height: 32px;
  flex: 0 0 32px;
  border-radius: var(--radius-sm);
  background: var(--color-text);
  color: var(--color-surface);
  font-weight: 900;
}

.dark-theme .shell-brand-mark {
  color: #101414;
}

.shell-brand-copy {
  display: grid;
  line-height: 1.15;
}

.shell-brand-name {
  font-size: 16px;
  font-weight: 850;
}

.shell-brand-copy small {
  color: var(--color-muted);
  font-size: 12px;
}

.shell-header-right {
  gap: 10px;
  min-width: 0;
}

.shell-user-menu {
  position: relative;
}

.shell-icon-btn,
.home-course-delete,
.feynman-input-btn {
  display: inline-flex;
  align-items: center;
  justify-content: center;
  border: 1px solid var(--color-border);
  border-radius: var(--radius);
  background: var(--color-surface);
  color: var(--color-text);
  cursor: pointer;
  transition: background 160ms ease, border-color 160ms ease, transform 160ms ease;
}

.shell-icon-btn {
  width: 38px;
  height: 38px;
  font-size: 18px;
}

.shell-icon-btn:hover,
.shell-text-btn:hover,
.shell-back-btn:hover,
.home-course-delete:hover {
  border-color: var(--color-border-strong);
  background: var(--color-panel);
}

.shell-user-badge {
  gap: 8px;
  border: 1px solid var(--color-border);
  border-radius: var(--radius);
  background: var(--color-surface);
  padding: 7px 10px;
  color: var(--color-muted);
  font-size: 14px;
  cursor: pointer;
  transition: background 160ms ease, border-color 160ms ease;
}

.shell-user-badge:hover,
.shell-user-badge[aria-expanded="true"] {
  border-color: var(--color-border-strong);
  background: var(--color-panel);
}

.user-avatar {
  display: inline-grid;
  place-items: center;
  width: 22px;
  height: 22px;
  border-radius: var(--radius-sm);
  background: var(--color-primary-soft);
  color: var(--color-primary);
  font-weight: 800;
  text-transform: uppercase;
}

.shell-user {
  color: var(--color-text);
  font-weight: 700;
}

.shell-logout-form {
  margin: 0;
}

.user-menu-panel {
  position: absolute;
  top: calc(100% + 10px);
  right: 0;
  width: min(380px, calc(100vw - 32px));
  display: grid;
  gap: 14px;
  border: 1px solid var(--color-border);
  border-radius: var(--radius);
  background: var(--color-surface);
  box-shadow: var(--shadow);
  padding: 16px;
  z-index: 80;
}

.user-menu-section {
  display: grid;
  gap: 10px;
}

.user-menu-head {
  display: flex;
  align-items: center;
  justify-content: space-between;
  gap: 12px;
}

.user-menu-head .eyebrow {
  margin-bottom: 0;
}

.user-menu-refresh {
  border: 1px solid var(--color-border);
  border-radius: var(--radius-sm);
  background: var(--color-panel);
  color: var(--color-muted);
  cursor: pointer;
  font-size: 12px;
  font-weight: 800;
  padding: 5px 8px;
}

.user-menu-refresh:hover {
  border-color: var(--color-border-strong);
  color: var(--color-text);
}

.user-menu-history {
  display: grid;
  gap: 8px;
  max-height: 280px;
  overflow-y: auto;
  padding-right: 2px;
}

.user-menu-history-item,
.user-menu-action {
  width: 100%;
  min-width: 0;
  border: 1px solid var(--color-border);
  border-radius: var(--radius);
  background: var(--color-bg);
  color: var(--color-text);
  cursor: pointer;
  text-align: left;
}

.user-menu-history-item {
  display: grid;
  gap: 3px;
  padding: 11px 12px;
}

.user-menu-history-item:hover,
.user-menu-action:hover {
  border-color: var(--color-primary);
  background: var(--color-primary-soft);
}

.user-menu-history-item strong,
.user-menu-history-item span,
.user-menu-history-item small {
  overflow-wrap: anywhere;
}

.user-menu-history-item strong {
  font-size: 14px;
  line-height: 1.25;
}

.user-menu-history-item span {
  color: var(--color-text);
  font-size: 13px;
}

.user-menu-history-item small {
  color: var(--color-muted);
  font-size: 12px;
  font-weight: 700;
}

.user-menu-actions {
  border-top: 1px solid var(--color-border);
  padding-top: 12px;
}

.user-menu-action {
  display: flex;
  align-items: center;
  gap: 8px;
  min-height: 38px;
  padding: 8px 10px;
  font-size: 14px;
  font-weight: 800;
}

.user-menu-logout {
  color: var(--color-error);
}

.shell-text-btn,
.shell-back-btn,
.resource-link,
.home-course-action,
.feedback-btn,
.submission-edit-btn,
.attachment-chip-remove,
.plan-subnav-item {
  border: 1px solid var(--color-border);
  border-radius: var(--radius);
  background: var(--color-surface);
  color: var(--color-text);
  cursor: pointer;
  font-size: 14px;
  font-weight: 750;
  transition: background 160ms ease, border-color 160ms ease, color 160ms ease, transform 160ms ease;
}

.shell-text-btn {
  padding: 8px 12px;
}

.checkin-streak-badge {
  display: inline-flex;
  align-items: center;
  min-height: 38px;
  border: 1px solid var(--color-border);
  border-radius: var(--radius);
  background: var(--color-panel);
  color: var(--color-muted);
  font-size: 13px;
  font-weight: 850;
  line-height: 1.2;
  padding: 7px 10px;
  white-space: nowrap;
}

.checkin-streak-badge.is-active {
  border-color: rgba(35, 117, 74, 0.35);
  background: var(--color-success-soft);
  color: var(--color-success);
}

.shell-main {
  padding: 30px 0 72px;
}

.shell-back-bar {
  position: sticky;
  top: 72px;
  z-index: 45;
  display: flex;
  margin-bottom: 18px;
  padding: 8px 0;
  background: rgba(245, 247, 247, 0.92);
  backdrop-filter: blur(14px);
}

.dark-theme .shell-back-bar {
  background: rgba(16, 20, 20, 0.92);
}

.shell-back-btn {
  display: inline-flex;
  align-items: center;
  gap: 8px;
  padding: 9px 12px;
}

.back-icon {
  font-size: 18px;
  line-height: 1;
}

/* Forms and buttons */
.field,
.form-group {
  display: grid;
  gap: 8px;
}

input,
textarea,
select {
  width: 100%;
  min-width: 0;
  border: 1px solid var(--color-border);
  border-radius: var(--radius);
  background: var(--color-surface);
  color: var(--color-text);
  padding: 12px 13px;
  transition: border-color 160ms ease, box-shadow 160ms ease, background 160ms ease;
}

input::placeholder,
textarea::placeholder {
  color: var(--color-soft);
}

input:focus,
textarea:focus,
select:focus {
  border-color: var(--color-primary);
  box-shadow: 0 0 0 4px rgba(31, 117, 106, 0.12);
  outline: none;
}

textarea {
  min-height: 112px;
  resize: vertical;
}

.btn {
  display: inline-flex;
  align-items: center;
  justify-content: center;
  min-height: 42px;
  max-width: 100%;
  border: 1px solid var(--color-primary);
  border-radius: var(--radius);
  background: var(--color-primary);
  color: #ffffff;
  cursor: pointer;
  font-size: 14px;
  font-weight: 800;
  line-height: 1.2;
  padding: 10px 16px;
  text-align: center;
  transition: background 160ms ease, border-color 160ms ease, transform 160ms ease, opacity 160ms ease;
}

.btn:hover {
  background: var(--color-primary-hover);
  border-color: var(--color-primary-hover);
  transform: translateY(-1px);
}

.btn:active {
  transform: translateY(0);
}

.btn:disabled,
button:disabled {
  cursor: not-allowed;
  opacity: 0.55;
  transform: none;
}

.btn-secondary {
  background: var(--color-surface);
  color: var(--color-text);
  border-color: var(--color-border);
}

.btn-secondary:hover {
  background: var(--color-panel);
  border-color: var(--color-border-strong);
  color: var(--color-text);
}

/* Dashboard */
.dashboard-hero {
  display: grid;
  grid-template-columns: minmax(0, 1fr) 340px;
  gap: 20px;
  align-items: stretch;
  border: 1px solid var(--color-border);
  border-radius: var(--radius);
  background: var(--color-surface);
  padding: 28px;
  box-shadow: var(--shadow-soft);
}

.dashboard-copy h1 {
  max-width: 760px;
  font-size: 38px;
  line-height: 1.16;
  font-weight: 900;
  margin-bottom: 14px;
}

.home-sub {
  max-width: 720px;
  color: var(--color-muted);
  margin-bottom: 24px;
}

.home-create-form {
  display: grid;
  gap: 16px;
  max-width: 760px;
}

.home-create-btn {
  width: fit-content;
  min-width: 154px;
}

.dashboard-panel {
  border: 1px solid var(--color-border);
  border-radius: var(--radius);
  background: var(--color-panel);
  padding: 18px;
  display: grid;
  align-content: center;
  gap: 12px;
}

.panel-row {
  display: grid;
  grid-template-columns: 42px minmax(0, 1fr);
  gap: 12px;
  border: 1px solid var(--color-border);
  border-radius: var(--radius);
  background: var(--color-surface);
  padding: 14px;
}

.panel-index {
  color: var(--color-primary);
  font-weight: 900;
}

.panel-row strong {
  display: block;
  margin-bottom: 3px;
}

.panel-row p {
  color: var(--color-muted);
  font-size: 14px;
}

.home-continue {
  margin-top: 26px;
}

.home-section-title {
  font-size: 22px;
  line-height: 1.25;
  margin-bottom: 14px;
}

.home-course-list {
  display: grid;
  gap: 12px;
}

.home-course-row {
  display: grid;
  grid-template-columns: minmax(0, 1fr) auto;
  gap: 18px;
  align-items: center;
  border: 1px solid var(--color-border);
  border-radius: var(--radius);
  background: var(--color-surface);
  padding: 16px;
  box-shadow: var(--shadow-soft);
  transition: border-color 160ms ease, transform 160ms ease, box-shadow 160ms ease;
}

.home-course-row:hover {
  border-color: var(--color-primary);
  transform: translateY(-1px);
}

.home-course-main {
  min-width: 0;
}

.home-course-main h3 {
  overflow-wrap: anywhere;
  font-size: 17px;
  margin-bottom: 5px;
}

.home-course-progress {
  color: var(--color-muted);
  font-size: 14px;
}

.home-course-actions {
  justify-content: flex-end;
  gap: 8px;
  flex-wrap: wrap;
}

.home-course-action {
  min-height: 38px;
  padding: 8px 12px;
  white-space: nowrap;
}

.home-course-action:hover,
.resource-link:hover,
.feedback-btn-secondary:hover,
.plan-subnav-item:hover {
  background: var(--color-panel);
  border-color: var(--color-border-strong);
}

.home-course-action-next {
  background: var(--color-primary);
  border-color: var(--color-primary);
  color: #ffffff;
}

.home-course-action-next:hover {
  background: var(--color-primary-hover);
  border-color: var(--color-primary-hover);
}

.home-course-delete {
  width: 38px;
  height: 38px;
  color: var(--color-error);
  font-size: 20px;
}

.home-continue-empty {
  border: 1px dashed var(--color-border);
  border-radius: var(--radius);
  padding: 18px;
  text-align: center;
}

/* Lesson shell */
.lesson-shell {
  display: grid;
  gap: 18px;
}

.lesson-header,
.lesson-outline,
.lesson-stage,
.exercise-list,
.feynman-brief,
.day-card {
  border: 1px solid var(--color-border);
  border-radius: var(--radius);
  background: var(--color-surface);
  box-shadow: var(--shadow-soft);
}

.lesson-header {
  justify-content: space-between;
  gap: 16px;
  padding: 22px;
  min-width: 0;
}

.lesson-header h2 {
  font-size: 26px;
  line-height: 1.2;
  margin-bottom: 5px;
  overflow-wrap: anywhere;
}

.lesson-header p {
  color: var(--color-muted);
}

.lesson-status {
  display: inline-flex;
  align-items: center;
  min-height: 32px;
  border: 1px solid var(--color-border);
  border-radius: var(--radius);
  background: var(--color-panel);
  color: var(--color-muted);
  padding: 6px 10px;
  font-size: 13px;
  font-weight: 800;
  white-space: nowrap;
}

.lesson-status.completed {
  border-color: rgba(35, 117, 74, 0.28);
  background: var(--color-success-soft);
  color: var(--color-success);
}

.lesson-outline,
.lesson-stage,
.exercise-list,
.feynman-brief {
  padding: 22px;
}

.lesson-outline h3,
.lesson-stage h3,
.exercise-list h3,
.feynman-brief h3 {
  font-size: 19px;
  line-height: 1.28;
  margin-bottom: 14px;
}

.lesson-stage > p,
.lesson-materials-hint,
.feynman-hint,
.lesson-stage-empty p {
  color: var(--color-muted);
  margin-bottom: 14px;
}

.lesson-stage-empty {
  border-style: dashed;
  background: transparent;
  box-shadow: none;
}

.lesson-complete-actions,
.feynman-done-actions {
  display: flex;
  justify-content: center;
  flex-wrap: wrap;
  gap: 10px;
}

/* Materials */
.lesson-materials-list,
.lesson-video-list,
.lesson-message-list,
.lesson-exercise-list,
.video-candidate-list {
  display: grid;
  gap: 12px;
}

.lesson-material,
.lesson-video-resource,
.lesson-message,
.feynman-iteration,
.exercise-item,
.video-candidate {
  border: 1px solid var(--color-border);
  border-radius: var(--radius);
  background: var(--color-bg);
}

.lesson-material {
  padding: 16px;
}

.lesson-material:hover,
.lesson-video-resource:hover,
.video-candidate-clickable:hover {
  border-color: var(--color-primary);
}

.lesson-material-head {
  flex-wrap: wrap;
  gap: 10px;
  margin-bottom: 8px;
}

.lesson-material-type,
.exercise-type,
.feedback-label,
.feynman-badge,
.video-tag {
  display: inline-flex;
  align-items: center;
  width: fit-content;
  min-height: 24px;
  border-radius: var(--radius-sm);
  font-size: 12px;
  font-weight: 850;
  line-height: 1.2;
  padding: 4px 8px;
}

.lesson-material-type,
.exercise-type {
  background: var(--color-panel-strong);
  color: var(--color-muted);
}

.lesson-material h4 {
  font-size: 16px;
  min-width: 0;
  overflow-wrap: anywhere;
}

.lesson-material h4 a {
  color: var(--color-primary);
}

.lesson-material-source {
  color: var(--color-muted);
  font-size: 13px;
  margin-bottom: 10px;
}

.lesson-material-focus {
  border-left: 3px solid var(--color-primary);
  background: var(--color-surface);
  border-radius: var(--radius-sm);
  color: var(--color-text);
  padding: 10px 12px;
  margin: 10px 0;
}

.lesson-material-actions,
.lesson-video-actions,
.feedback-actions,
.video-candidate-actions {
  display: flex;
  flex-wrap: wrap;
  gap: 8px;
  margin-top: 12px;
}

.video-feedback-actions {
  display: inline-flex;
  flex-wrap: wrap;
  gap: 6px;
}

.video-candidate-panel {
  border-top: 1px dashed var(--color-border);
  padding-top: 10px;
}

.video-candidate-panel summary {
  align-items: center;
  color: var(--color-primary);
  cursor: pointer;
  display: flex;
  font-size: 13px;
  font-weight: 850;
  gap: 8px;
  justify-content: space-between;
  list-style: none;
  user-select: none;
}

.video-candidate-panel summary::-webkit-details-marker {
  display: none;
}

.video-candidate-panel summary::after {
  content: "展开";
  border: 1px solid var(--color-border);
  border-radius: var(--radius-sm);
  color: var(--color-muted);
  font-size: 12px;
  font-weight: 750;
  line-height: 1.2;
  padding: 4px 8px;
}

.video-candidate-panel[open] summary {
  margin-bottom: 10px;
}

.video-candidate-panel[open] summary::after {
  content: "收起";
}

.video-candidate-attr {
  margin-top: 8px;
  font-size: 12px;
  color: var(--color-muted);
  border-top: 1px dashed var(--color-border);
  padding-top: 6px;
}

.video-candidate-attr summary {
  cursor: pointer;
  user-select: none;
  font-weight: 600;
}

.video-candidate-attr-body {
  display: grid;
  grid-template-columns: 1fr 1fr;
  gap: 12px;
  margin-top: 8px;
}

.video-candidate-attr-body table {
  border-collapse: collapse;
  width: 100%;
}

.video-candidate-attr-body table td {
  padding: 2px 6px 2px 0;
  font-variant-numeric: tabular-nums;
}

.video-candidate-attr-body table td:first-child {
  color: var(--color-muted);
}

.video-candidate-attr-caps ul {
  margin: 4px 0 0;
  padding-left: 16px;
}

.video-candidate-attr-caps li {
  margin-bottom: 4px;
}

@media (max-width: 640px) {
  .video-candidate-attr-body { grid-template-columns: 1fr; }
}

.video-feedback-btn {
  min-height: 30px;
  border: 1px solid var(--color-border);
  border-radius: var(--radius-sm);
  background: var(--color-surface);
  color: var(--color-muted);
  font-size: 12px;
  font-weight: 750;
  padding: 5px 8px;
  cursor: pointer;
}

.video-feedback-btn:hover,
.video-feedback-btn.is-active {
  border-color: var(--color-primary);
  color: var(--color-primary);
  background: var(--color-primary-soft);
}

.resource-link {
  display: inline-flex;
  align-items: center;
  justify-content: center;
  min-height: 34px;
  padding: 7px 10px;
  color: var(--color-primary);
  background: var(--color-surface);
  text-align: center;
}

/* Feynman */
.feynman-goal,
.feynman-probe-question,
.lesson-checkpoints,
.feedback-suggested,
.submission-view {
  border: 1px solid var(--color-border);
  border-radius: var(--radius);
  background: var(--color-panel);
  padding: 14px;
}

.feynman-goal {
  border-left: 3px solid var(--color-primary);
  margin-bottom: 18px;
}

.feynman-block {
  margin-top: 18px;
}

.feynman-block h4 {
  font-size: 15px;
  margin-bottom: 8px;
}

.feynman-block ol,
.feynman-block ul,
.feynman-gap-report ul {
  margin: 0;
  padding-left: 22px;
}

.feynman-block li,
.feynman-gap-report li {
  margin: 5px 0;
}

.feynman-term {
  display: inline-flex;
  margin: 0 6px 8px 0;
  border: 1px solid var(--color-border);
  border-radius: var(--radius-sm);
  background: var(--color-surface);
  color: var(--color-primary);
  padding: 5px 9px;
  font-size: 13px;
  font-weight: 750;
}

.feynman-iterations {
  display: grid;
  gap: 12px;
}

.feynman-iteration {
  padding: 16px;
}

.feynman-iteration-passed {
  border-color: rgba(35, 117, 74, 0.35);
  background: var(--color-success-soft);
}

.feynman-iteration-header {
  display: flex;
  align-items: center;
  justify-content: space-between;
  gap: 12px;
  margin-bottom: 12px;
}

.feynman-iteration-body {
  display: grid;
  gap: 10px;
}

.feynman-iteration-body h4 {
  color: var(--color-muted);
  font-size: 14px;
}

.feynman-badge {
  border: 1px solid var(--color-border);
  background: var(--color-surface);
  color: var(--color-muted);
}

.feynman-badge-pass {
  border-color: rgba(35, 117, 74, 0.28);
  background: var(--color-success-soft);
  color: var(--color-success);
}

.feynman-gap-report {
  border: 1px solid var(--color-border);
  border-radius: var(--radius);
  background: var(--color-surface);
  padding: 14px;
}

.feynman-gap-fail {
  border-color: rgba(179, 57, 57, 0.24);
  background: var(--color-error-soft);
}

.feynman-next-focus {
  color: var(--color-success);
}

.feynman-action {
  border-left: 4px solid var(--color-primary);
}

.feynman-form {
  display: grid;
  gap: 12px;
}

/* Course knowledge */
.knowledge-panel {
  display: grid;
  gap: 16px;
}

.knowledge-panel-head {
  display: flex;
  align-items: flex-start;
  justify-content: space-between;
  gap: 14px;
  min-width: 0;
}

.knowledge-panel-head h3 {
  margin-bottom: 0;
}

.knowledge-panel-status {
  display: inline-flex;
  align-items: center;
  min-height: 28px;
  border: 1px solid var(--color-border);
  border-radius: var(--radius-sm);
  background: var(--color-panel);
  color: var(--color-muted);
  font-size: 12px;
  font-weight: 850;
  padding: 5px 8px;
  white-space: nowrap;
}

.knowledge-panel-body {
  display: grid;
  gap: 16px;
}

.knowledge-panel-empty {
  border: 1px dashed var(--color-border);
  border-radius: var(--radius);
  padding: 16px;
  text-align: center;
}

.knowledge-metrics {
  display: grid;
  grid-template-columns: repeat(4, minmax(0, 1fr));
  gap: 10px;
}

.knowledge-metric {
  min-width: 0;
  border: 1px solid var(--color-border);
  border-radius: var(--radius);
  background: var(--color-bg);
  padding: 14px;
}

.knowledge-metric strong {
  display: block;
  color: var(--color-primary);
  font-size: 26px;
  line-height: 1;
  margin-bottom: 7px;
}

.knowledge-metric span {
  color: var(--color-muted);
  font-size: 13px;
  font-weight: 750;
}

.knowledge-section {
  display: grid;
  gap: 10px;
  min-width: 0;
}

.knowledge-section h4 {
  font-size: 15px;
  line-height: 1.25;
}

.knowledge-timeline {
  display: grid;
  gap: 10px;
}

.knowledge-day {
  display: grid;
  grid-template-columns: 72px minmax(0, 1fr);
  gap: 12px;
  align-items: start;
  border: 1px solid var(--color-border);
  border-radius: var(--radius);
  background: var(--color-bg);
  padding: 12px;
}

.knowledge-day-index {
  border-radius: var(--radius-sm);
  background: var(--color-primary-soft);
  color: var(--color-primary);
  font-size: 13px;
  font-weight: 900;
  line-height: 1.2;
  padding: 7px 8px;
  text-align: center;
  white-space: nowrap;
}

.knowledge-day-main {
  min-width: 0;
}

.knowledge-day-main strong,
.knowledge-weak-item strong,
.knowledge-qa-item strong {
  display: block;
  overflow-wrap: anywhere;
}

.knowledge-day-main p,
.knowledge-weak-item p,
.knowledge-qa-item p,
.knowledge-section-clear p {
  color: var(--color-muted);
  font-size: 13px;
  line-height: 1.55;
  margin-top: 5px;
}

.knowledge-grid {
  display: grid;
  grid-template-columns: minmax(0, 1fr) minmax(0, 1fr);
  gap: 16px;
}

.knowledge-chip-list {
  display: flex;
  flex-wrap: wrap;
  gap: 8px;
}

.knowledge-chip {
  display: inline-flex;
  align-items: center;
  gap: 6px;
  min-height: 30px;
  border: 1px solid var(--color-border);
  border-radius: var(--radius-sm);
  background: var(--color-surface);
  color: var(--color-primary);
  font-size: 13px;
  font-weight: 800;
  padding: 6px 9px;
}

.knowledge-chip small {
  color: var(--color-muted);
  font-size: 11px;
  font-weight: 750;
}

.knowledge-weak-list,
.knowledge-qa-list {
  display: grid;
  gap: 8px;
}

.knowledge-weak-item,
.knowledge-qa-item {
  border: 1px solid var(--color-border);
  border-radius: var(--radius);
  background: var(--color-bg);
  padding: 12px;
}

.knowledge-weak-item {
  border-left: 3px solid var(--color-amber);
}

.knowledge-weak-item span,
.knowledge-qa-item span {
  display: block;
  color: var(--color-muted);
  font-size: 12px;
  font-weight: 800;
  margin-bottom: 5px;
}

.knowledge-section-clear {
  border: 1px solid rgba(35, 117, 74, 0.24);
  border-radius: var(--radius);
  background: var(--color-success-soft);
  padding: 12px;
}

.feynman-probe-question {
  color: var(--color-text);
  font-weight: 750;
  white-space: pre-wrap;
}

.feynman-probe-current {
  margin-bottom: 0.75rem;
}

.feynman-cap {
  border-left-color: var(--color-error);
}

.feynman-done {
  border-left: 4px solid var(--color-success);
}

.feynman-mastery ul {
  display: flex;
  flex-wrap: wrap;
  gap: 8px;
  list-style: none;
  margin: 0;
  padding: 0;
}

.feynman-mastery li {
  border: 1px solid var(--color-border);
  border-radius: var(--radius);
  background: var(--color-bg);
  padding: 8px 10px;
  font-size: 14px;
}

/* Legacy chat bubbles kept for compatibility */
.feynman-messages {
  display: grid;
  gap: 12px;
  max-height: 480px;
  overflow: auto;
  border: 1px solid var(--color-border);
  border-radius: var(--radius);
  background: var(--color-bg);
  padding: 16px;
}

.feynman-message {
  max-width: 78%;
}

.feynman-message-user {
  justify-self: end;
}

.feynman-message-role {
  color: var(--color-muted);
  font-size: 12px;
  font-weight: 800;
  margin-bottom: 4px;
}

.feynman-message-content {
  border: 1px solid var(--color-border);
  border-radius: var(--radius);
  background: var(--color-surface);
  padding: 12px;
}

.feynman-message-user .feynman-message-content {
  background: var(--color-primary);
  border-color: var(--color-primary);
  color: #ffffff;
}

.feynman-input-container {
  display: grid;
  grid-template-columns: minmax(0, 1fr) 48px;
  gap: 10px;
}

.feynman-chat-input {
  min-height: 48px;
}

.feynman-input-btn {
  width: 48px;
  height: 48px;
  background: var(--color-primary);
  color: #ffffff;
}

.feynman-status-row {
  color: var(--color-muted);
  font-size: 13px;
  margin-top: 10px;
}

/* Video resources */
.lesson-video-header {
  justify-content: space-between;
  gap: 12px;
  margin-bottom: 14px;
  min-width: 0;
}

.lesson-video-header span {
  color: var(--color-muted);
  font-size: 14px;
}

.video-refresh-btn {
  white-space: nowrap;
}

.lesson-video-resource {
  padding: 16px;
  display: grid;
  gap: 12px;
}

.lesson-video-resource-main strong {
  display: block;
  margin-bottom: 6px;
}

.lesson-video-resource-main p,
.lesson-video-resource-main small,
.video-candidate-main small,
.video-candidate-main p,
.video-candidate-empty {
  display: block;
  color: var(--color-muted);
  font-size: 13px;
  margin-top: 6px;
}

.lesson-video-query {
  border-radius: var(--radius-sm);
  background: var(--color-surface);
  border: 1px solid var(--color-border);
  color: var(--color-primary);
  font-family: var(--font-mono);
  font-size: 13px;
  padding: 8px 10px;
  margin-top: 8px;
  overflow-wrap: anywhere;
}

.lesson-video-tags,
.video-candidate-tags {
  display: flex;
  flex-wrap: wrap;
  gap: 6px;
}

.video-tag-cover {
  background: var(--color-blue-soft);
  color: var(--color-blue);
}

.video-tag-avoid {
  background: var(--color-amber-soft);
  color: var(--color-amber);
}

.video-candidate {
  display: grid;
  grid-template-columns: 76px minmax(0, 1fr);
  gap: 14px;
  padding: 14px;
}

.video-candidate-clickable {
  cursor: pointer;
}

.video-candidate-failed {
  color: var(--color-error);
  background: var(--color-error-soft);
}

.video-candidate-score {
  display: grid;
  align-content: start;
  gap: 3px;
}

.video-candidate-score strong {
  color: var(--color-text);
  font-size: 12px;
  font-weight: 750;
  line-height: 1.2;
  white-space: nowrap;
}

.video-candidate-score span,
.video-candidate-score em {
  color: var(--color-muted);
  font-size: 12px;
  font-style: normal;
  font-weight: 750;
}

.video-candidate-main {
  min-width: 0;
}

.video-candidate-main > a {
  color: var(--color-primary);
  font-weight: 800;
  overflow-wrap: anywhere;
}

/* Messages and practice */
.lesson-message {
  padding: 16px;
}

.lesson-message-ai {
  background: var(--color-bg);
}

.lesson-message-user {
  background: var(--color-primary-soft);
}

.lesson-message-meta {
  display: flex;
  align-items: center;
  justify-content: space-between;
  gap: 12px;
  color: var(--color-muted);
  font-size: 13px;
  font-weight: 750;
  margin-bottom: 10px;
}

.lesson-checkpoints {
  margin-top: 14px;
}

.lesson-checkpoints ul {
  margin: 10px 0 0;
  padding-left: 20px;
}

.lesson-chat-form {
  display: grid;
  gap: 12px;
}

.lesson-chat-form textarea {
  min-height: 96px;
}

.exercise-list {
  margin-bottom: 18px;
}

.exercise-list-header {
  justify-content: space-between;
  gap: 12px;
  margin-bottom: 14px;
  min-width: 0;
}

.exercise-list-header h3,
.exercise-list-header strong {
  font-size: 18px;
}

.exercise-progress {
  border: 1px solid var(--color-border);
  border-radius: var(--radius);
  background: var(--color-panel);
  color: var(--color-muted);
  padding: 5px 8px;
  font-size: 13px;
  font-weight: 800;
}

.exercise-item {
  padding: 16px;
  margin-bottom: 12px;
}

.exercise-item:last-child {
  margin-bottom: 0;
}

.exercise-done {
  border-color: rgba(35, 117, 74, 0.35);
}

.exercise-question {
  display: grid;
  grid-template-columns: auto minmax(0, 1fr);
  gap: 10px;
  align-items: start;
}

.exercise-question-text {
  font-weight: 750;
  overflow-wrap: anywhere;
}

.submission-form {
  display: grid;
  gap: 12px;
  margin-top: 14px;
  padding-top: 14px;
  border-top: 1px dashed var(--color-border);
}

.submission-meta {
  display: flex;
  justify-content: space-between;
  gap: 10px;
  color: var(--color-muted);
  font-size: 13px;
  margin-bottom: 8px;
}

.submission-content {
  font-size: 14px;
}

.submission-edit-btn,
.attachment-chip-remove {
  width: fit-content;
  padding: 7px 10px;
  color: var(--color-primary);
}

.submission-controls {
  justify-content: space-between;
  gap: 12px;
  flex-wrap: wrap;
}

.submission-hint {
  color: var(--color-muted);
  font-size: 13px;
}

/* Attachments */
.attachment-picker,
.attachment-existing {
  border: 1px dashed var(--color-border);
  border-radius: var(--radius);
  background: var(--color-surface);
  padding: 12px;
}

.attachment-picker {
  display: grid;
  gap: 8px;
}

.attachment-picker-label input[type="file"] {
  display: none;
}

.attachment-picker-btn {
  display: inline-flex;
  align-items: center;
  width: fit-content;
  min-height: 34px;
  border: 1px solid var(--color-border);
  border-radius: var(--radius);
  background: var(--color-panel);
  color: var(--color-text);
  cursor: pointer;
  padding: 7px 10px;
  font-size: 14px;
  font-weight: 800;
}

.attachment-picker-btn:hover {
  border-color: var(--color-border-strong);
}

.attachment-existing-title {
  color: var(--color-muted);
  font-size: 13px;
  font-weight: 800;
  margin-bottom: 8px;
}

.attachment-list,
.attachment-pending-list {
  display: grid;
  gap: 8px;
  list-style: none;
  margin: 8px 0 0;
  padding: 0;
}

.attachment-chip,
.attachment-pending-item {
  display: flex;
  align-items: center;
  justify-content: space-between;
  gap: 10px;
  flex-wrap: wrap;
  border: 1px solid var(--color-border);
  border-radius: var(--radius);
  background: var(--color-bg);
  padding: 8px 10px;
  font-size: 13px;
}

.attachment-chip-link {
  display: inline-flex;
  align-items: center;
  gap: 6px;
  min-width: 0;
  color: var(--color-text);
  font-weight: 750;
}

.attachment-chip-name {
  overflow-wrap: anywhere;
}

.attachment-chip-size {
  color: var(--color-muted);
}

.attachment-chip-flag {
  color: var(--color-success);
  font-weight: 800;
}

.attachment-chip-flag-warn {
  color: var(--color-amber);
}

.attachment-chip-remove {
  color: var(--color-error);
  background: var(--color-surface);
}

/* Feedback */
.feedback-card {
  display: grid;
  gap: 14px;
  margin-top: 14px;
  border: 1px solid var(--color-border);
  border-radius: var(--radius);
  background: var(--color-surface);
  padding: 16px;
}

.feedback-verdict-correct {
  border-color: rgba(35, 117, 74, 0.35);
  background: var(--color-success-soft);
}

.feedback-verdict-incorrect {
  border-color: rgba(179, 57, 57, 0.3);
  background: var(--color-error-soft);
}

.feedback-verdict-partial {
  border-color: rgba(168, 100, 27, 0.32);
  background: var(--color-amber-soft);
}

.feedback-header {
  justify-content: space-between;
  gap: 12px;
}

.feedback-label {
  background: var(--color-surface);
  color: var(--color-muted);
  margin-right: 8px;
}

.feedback-verdict {
  font-weight: 900;
}

.feedback-time {
  color: var(--color-muted);
  font-size: 13px;
}

.feedback-summary {
  color: var(--color-text);
}

.feedback-grid {
  display: grid;
  grid-template-columns: repeat(2, minmax(0, 1fr));
  gap: 12px;
}

.feedback-list {
  display: grid;
  gap: 8px;
}

.feedback-list strong,
.feedback-suggested strong {
  font-size: 14px;
}

.feedback-list ul {
  margin: 0;
  padding-left: 20px;
}

.feedback-list li {
  color: var(--color-muted);
  margin: 4px 0;
}

.feedback-btn {
  display: inline-flex;
  align-items: center;
  justify-content: center;
  min-height: 34px;
  border-color: var(--color-primary);
  background: var(--color-primary);
  color: #ffffff;
  padding: 7px 11px;
}

.feedback-btn:hover {
  background: var(--color-primary-hover);
}

.feedback-btn-secondary {
  border-color: var(--color-border);
  background: var(--color-surface);
  color: var(--color-text);
}

/* Daily cards and calendar compatibility */
.day-card {
  padding: 18px;
}

.day-header {
  display: flex;
  flex-wrap: wrap;
  gap: 8px;
  align-items: center;
  margin-bottom: 12px;
}

.day-label,
.day-date {
  display: inline-flex;
  border-radius: var(--radius);
  background: var(--color-panel);
  color: var(--color-muted);
  padding: 5px 8px;
  font-size: 13px;
  font-weight: 850;
}

.day-title {
  font-weight: 900;
}

.day-actions {
  margin-top: 14px;
}

.day-content-empty {
  color: var(--color-muted);
}

.calendar-wrapper {
  display: grid;
  grid-template-columns: repeat(auto-fit, minmax(280px, 1fr));
  gap: 14px;
}

.calendar-month,
.day-detail-panel,
.progress-overview,
.today-focus,
.weak-points {
  border: 1px solid var(--color-border);
  border-radius: var(--radius);
  background: var(--color-surface);
  padding: 16px;
}

.calendar-month-title {
  font-weight: 900;
  margin-bottom: 10px;
}

.calendar-grid {
  display: grid;
  grid-template-columns: repeat(7, minmax(0, 1fr));
  gap: 6px;
}

.calendar-weekday {
  color: var(--color-muted);
  font-size: 12px;
  text-align: center;
  font-weight: 800;
}

.calendar-cell {
  min-height: 58px;
  border: 1px solid var(--color-border);
  border-radius: var(--radius-sm);
  background: var(--color-bg);
  padding: 6px;
  overflow: hidden;
}

.calendar-cell-active {
  cursor: pointer;
}

.calendar-cell-active:hover,
.calendar-cell-active.selected {
  border-color: var(--color-primary);
  background: var(--color-primary-soft);
}

.calendar-cell-disabled {
  opacity: 0.45;
}

.calendar-day-num {
  font-weight: 900;
  font-size: 13px;
}

.calendar-day-title,
.calendar-day-progress {
  color: var(--color-muted);
  font-size: 11px;
}

.calendar-cell.completed {
  border-color: rgba(35, 117, 74, 0.35);
}

.calendar-cell.partial {
  border-color: rgba(168, 100, 27, 0.35);
}

.calendar-cell.is-today .calendar-day-num {
  color: var(--color-primary);
}

/* Markdown */
.markdown-body {
  color: var(--color-text);
  font-size: 15px;
  line-height: 1.65;
  overflow-wrap: anywhere;
}

.markdown-body > :first-child {
  margin-top: 0;
}

.markdown-body > :last-child {
  margin-bottom: 0;
}

.markdown-body h1,
.markdown-body h2,
.markdown-body h3,
.markdown-body h4 {
  margin: 18px 0 8px;
  line-height: 1.3;
}

.markdown-body h1 {
  font-size: 22px;
}

.markdown-body h2 {
  font-size: 19px;
}

.markdown-body h3 {
  font-size: 17px;
}

.markdown-body p,
.markdown-body ul,
.markdown-body ol,
.markdown-body blockquote,
.markdown-body pre {
  margin: 0 0 12px;
}

.markdown-body ul,
.markdown-body ol {
  padding-left: 22px;
}

.markdown-body li {
  margin: 4px 0;
}

.markdown-body a,
.markdown-inline a {
  color: var(--color-primary);
  font-weight: 750;
}

.markdown-body code,
.markdown-inline code {
  border: 1px solid var(--color-border);
  border-radius: var(--radius-sm);
  background: var(--color-panel);
  font-family: var(--font-mono);
  font-size: 0.92em;
  padding: 1px 5px;
}

.markdown-body pre {
  border: 1px solid var(--color-border);
  border-radius: var(--radius);
  background: var(--color-panel);
  overflow-x: auto;
  padding: 14px;
}

.markdown-body pre code {
  border: 0;
  background: transparent;
  padding: 0;
}

.markdown-body blockquote {
  border-left: 3px solid var(--color-primary);
  color: var(--color-muted);
  padding-left: 12px;
}

/* User feedback */
.modal-open {
  overflow: hidden;
}

.user-feedback-modal {
  position: fixed;
  inset: 0;
  z-index: 80;
  display: grid;
  place-items: center;
  padding: 20px;
}

.user-feedback-backdrop {
  position: absolute;
  inset: 0;
  background: rgba(16, 20, 20, 0.54);
}

.user-feedback-panel {
  position: relative;
  width: min(560px, 100%);
  max-height: calc(100vh - 40px);
  overflow-y: auto;
  display: grid;
  gap: 16px;
  border: 1px solid var(--color-border);
  border-radius: var(--radius);
  background: var(--color-surface);
  box-shadow: var(--shadow);
  padding: 22px;
}

.user-feedback-head,
.user-feedback-actions,
.admin-feedback-toolbar,
.admin-feedback-card-head,
.admin-feedback-meta,
.admin-feedback-details,
.admin-feedback-filters {
  display: flex;
  align-items: center;
}

.user-feedback-head,
.admin-feedback-toolbar,
.admin-feedback-card-head {
  justify-content: space-between;
  gap: 16px;
}

.user-feedback-head h2,
.admin-feedback-toolbar h1,
.admin-feedback-card h2 {
  font-size: 24px;
  line-height: 1.25;
  font-weight: 850;
}

.feedback-form-grid {
  display: grid;
  grid-template-columns: minmax(0, 1fr) minmax(0, 1fr);
  gap: 14px;
}

.user-feedback-status {
  min-height: 22px;
  color: var(--color-muted);
  font-size: 14px;
}

.user-feedback-status.is-error {
  color: var(--color-error);
}

.user-feedback-status.is-success {
  color: var(--color-success);
}

.user-feedback-actions {
  justify-content: flex-end;
  gap: 10px;
}

/* Admin feedback */
.admin-feedback-toolbar {
  margin-bottom: 18px;
}

.admin-feedback-filters {
  gap: 10px;
}

.admin-feedback-filters select {
  min-width: 148px;
}

.admin-feedback-list {
  display: grid;
  gap: 14px;
}

.admin-feedback-card {
  display: grid;
  gap: 14px;
  border: 1px solid var(--color-border);
  border-radius: var(--radius);
  background: var(--color-surface);
  box-shadow: var(--shadow-soft);
  padding: 18px;
}

.admin-feedback-meta {
  flex-wrap: wrap;
  gap: 8px;
  color: var(--color-muted);
  font-size: 13px;
  font-weight: 700;
}

.admin-feedback-meta span {
  border: 1px solid var(--color-border);
  border-radius: var(--radius-sm);
  background: var(--color-panel);
  padding: 3px 7px;
}

.admin-feedback-status {
  border-radius: var(--radius-sm);
  padding: 5px 9px;
  font-size: 13px;
  font-weight: 850;
  white-space: nowrap;
}

.admin-feedback-status.status-open {
  background: var(--color-amber-soft);
  color: var(--color-amber);
}

.admin-feedback-status.status-reviewing {
  background: var(--color-blue-soft);
  color: var(--color-blue);
}

.admin-feedback-status.status-done {
  background: var(--color-success-soft);
  color: var(--color-success);
}

.admin-feedback-status.status-archived {
  background: var(--color-panel-strong);
  color: var(--color-muted);
}

.admin-feedback-message {
  white-space: pre-wrap;
  overflow-wrap: anywhere;
}

.admin-feedback-details {
  align-items: stretch;
  gap: 10px;
}

.admin-feedback-details div {
  min-width: 0;
  flex: 1;
  border: 1px solid var(--color-border);
  border-radius: var(--radius);
  background: var(--color-panel);
  padding: 10px;
}

.admin-feedback-details dt {
  color: var(--color-muted);
  font-size: 12px;
  font-weight: 800;
  margin-bottom: 4px;
}

.admin-feedback-details dd {
  margin: 0;
  overflow-wrap: anywhere;
  font-size: 14px;
}

.admin-feedback-edit {
  display: grid;
  grid-template-columns: 150px minmax(0, 1fr) auto;
  gap: 10px;
  align-items: start;
}

.admin-feedback-edit textarea {
  min-height: 44px;
}

/* Admin analytics */
.admin-analytics-toolbar,
.admin-analytics-filters,
.admin-analytics-panel-head,
.admin-analytics-chart,
.admin-analytics-bar,
.admin-analytics-stat strong {
  display: flex;
  align-items: center;
}

.admin-analytics-toolbar,
.admin-analytics-panel-head {
  justify-content: space-between;
  gap: 16px;
}

.admin-analytics-toolbar {
  margin-bottom: 18px;
}

.admin-analytics-toolbar h1 {
  font-size: 24px;
  line-height: 1.25;
  font-weight: 850;
}

.admin-analytics-toolbar p,
.admin-analytics-panel-head p,
.admin-analytics-panel-head span {
  color: var(--color-muted);
  font-size: 13px;
}

.admin-analytics-filters {
  gap: 10px;
}

.admin-analytics-filters select {
  min-width: 126px;
}

.admin-analytics-stats {
  display: grid;
  grid-template-columns: repeat(3, minmax(0, 1fr));
  gap: 12px;
  margin-bottom: 16px;
}

.admin-analytics-stat {
  display: grid;
  gap: 6px;
  min-width: 0;
  border: 1px solid var(--color-border);
  border-radius: var(--radius);
  background: var(--color-surface);
  box-shadow: var(--shadow-soft);
  padding: 14px 16px;
}

.admin-analytics-stat span,
.admin-analytics-stat small {
  color: var(--color-muted);
  font-size: 13px;
  font-weight: 700;
}

.admin-analytics-stat strong {
  gap: 8px;
  flex-wrap: wrap;
  color: var(--color-text);
  font-size: 28px;
  line-height: 1.1;
  font-weight: 850;
}

.admin-analytics-stat-trend {
  border-radius: var(--radius-sm);
  background: var(--color-panel-strong);
  padding: 4px 7px;
  font-size: 13px !important;
  line-height: 1;
}

.admin-analytics-stat-trend.is-up {
  background: var(--color-success-soft);
  color: var(--color-success);
}

.admin-analytics-stat-trend.is-down {
  background: var(--color-error-soft);
  color: var(--color-error);
}

.admin-analytics-panel {
  display: grid;
  gap: 16px;
  border: 1px solid var(--color-border);
  border-radius: var(--radius);
  background: var(--color-surface);
  box-shadow: var(--shadow-soft);
  padding: 18px;
  margin-top: 16px;
}

.admin-analytics-panel-head h2 {
  font-size: 19px;
  line-height: 1.25;
  font-weight: 850;
}

.admin-analytics-chart {
  align-items: end;
  gap: 6px;
  min-height: 190px;
  overflow-x: auto;
  padding: 6px 2px 2px;
}

.admin-analytics-bar {
  flex: 1 0 28px;
  min-width: 28px;
  flex-direction: column;
  justify-content: end;
  gap: 6px;
}

.admin-analytics-bar-value,
.admin-analytics-bar-label {
  color: var(--color-muted);
  font-size: 11px;
  white-space: nowrap;
}

.admin-analytics-bar-track {
  width: 100%;
  height: 144px;
  display: flex;
  align-items: end;
  justify-content: center;
  border-radius: var(--radius-sm);
  background: var(--color-panel);
  overflow: hidden;
}

.admin-analytics-bar-track i {
  display: block;
  width: 100%;
  min-height: 8px;
  border-radius: var(--radius-sm) var(--radius-sm) 0 0;
  background: linear-gradient(180deg, var(--color-primary), var(--color-blue));
}

.admin-analytics-table-wrap {
  overflow-x: auto;
}

.admin-analytics-table {
  width: 100%;
  min-width: 760px;
  border-collapse: collapse;
}

.admin-analytics-table th,
.admin-analytics-table td {
  border-bottom: 1px solid var(--color-border);
  padding: 10px 8px;
  text-align: left;
  vertical-align: top;
  font-size: 14px;
}

.admin-analytics-table th {
  color: var(--color-muted);
  font-size: 12px;
  font-weight: 850;
}

.admin-analytics-table td strong,
.admin-analytics-table td small {
  display: block;
}

.admin-analytics-table td small {
  color: var(--color-muted);
  font-size: 12px;
  margin-top: 2px;
}

@media (max-width: 900px) {
  .auth-layout,
  .dashboard-hero {
    grid-template-columns: 1fr;
  }

  .auth-panel {
    min-height: auto;
  }

  .dashboard-copy h1 {
    font-size: 32px;
  }

  .feedback-grid {
    grid-template-columns: 1fr;
  }

  .admin-analytics-stats {
    grid-template-columns: repeat(2, minmax(0, 1fr));
  }
}

@media (max-width: 720px) {
  body {
    font-size: 15px;
  }

  input,
  textarea,
  select {
    font-size: 16px;
  }

  .shell {
    width: min(100% - 24px, 1180px);
  }

  .shell-header {
    min-height: 64px;
    gap: 12px;
    padding: 10px 0;
  }

  .shell-brand-copy small {
    display: none;
  }

  .shell-brand-name {
    max-width: 8em;
    overflow: hidden;
    text-overflow: ellipsis;
    white-space: nowrap;
  }

  .shell-header-right {
    gap: 6px;
    flex: 0 0 auto;
  }

  .shell-main {
    padding: 18px 0 48px;
  }

  .shell-back-bar {
    top: 64px;
    margin-bottom: 12px;
  }

  .shell-back-btn,
  .shell-text-btn,
  .home-course-action,
  .resource-link,
  .feedback-btn,
  .submission-edit-btn,
  .attachment-picker-btn {
    min-height: 42px;
  }

  .dashboard-hero,
  .lesson-header,
  .lesson-outline,
  .lesson-stage,
  .exercise-list,
  .feynman-brief,
  .auth-card,
  .auth-panel {
    padding: 18px;
  }

  .dashboard-hero {
    gap: 16px;
  }

  .dashboard-copy h1,
  .auth-panel h2 {
    font-size: 28px;
  }

  .home-create-btn,
  .auth-btn,
  .lesson-chat-form .btn,
  .feynman-form .btn {
    width: 100%;
  }

  .home-course-row {
    grid-template-columns: 1fr;
    gap: 14px;
    padding: 14px;
  }

  .home-course-actions {
    display: grid;
    grid-template-columns: minmax(0, 1fr) 42px;
    justify-content: stretch;
  }

  .home-course-action {
    width: 100%;
  }

  .lesson-header {
    align-items: flex-start;
    flex-direction: column;
  }

  .lesson-status {
    white-space: normal;
  }

  .lesson-video-header,
  .exercise-list-header,
  .feedback-header,
  .feynman-iteration-header,
  .knowledge-panel-head,
  .submission-controls,
  .lesson-message-meta {
    align-items: flex-start;
    flex-direction: column;
  }

  .video-refresh-btn,
  .lesson-video-header .resource-link,
  .exercise-progress {
    width: 100%;
  }

  .lesson-material-actions,
  .lesson-video-actions,
  .feedback-actions,
  .video-candidate-actions,
  .lesson-complete-actions,
  .feynman-done-actions,
  .knowledge-metrics,
  .knowledge-grid,
  .feedback-form-grid,
  .admin-feedback-details,
  .admin-feedback-edit {
    display: grid;
    grid-template-columns: 1fr;
    width: 100%;
  }

  .user-feedback-head,
  .admin-feedback-toolbar,
  .admin-feedback-card-head,
  .admin-feedback-filters {
    align-items: flex-start;
    flex-direction: column;
  }

  .admin-feedback-filters,
  .admin-feedback-filters .btn,
  .admin-feedback-filters select,
  .user-feedback-actions,
  .user-feedback-actions .btn {
    width: 100%;
  }

  .video-candidate {
    grid-template-columns: 1fr;
    gap: 12px;
    padding: 13px;
  }

  .knowledge-day {
    grid-template-columns: 1fr;
  }

  .knowledge-day-index {
    width: fit-content;
    text-align: left;
  }

  .video-candidate-score {
    display: flex;
    align-items: center;
    gap: 8px;
  }

  .video-candidate-score strong {
    font-size: 12px;
  }

  .video-feedback-actions {
    display: grid;
    grid-template-columns: repeat(3, minmax(0, 1fr));
    width: 100%;
  }

  .video-feedback-btn {
    min-height: 34px;
    padding-left: 6px;
    padding-right: 6px;
  }

  .feynman-message {
    max-width: 94%;
  }

  .feedback-card,
  .lesson-material,
  .lesson-video-resource,
  .lesson-message,
  .exercise-item,
  .feynman-iteration,
  .knowledge-metric,
  .knowledge-day,
  .knowledge-weak-item,
  .knowledge-qa-item {
    padding: 14px;
  }

  .markdown-body pre {
    max-width: 100%;
  }
}

@media (max-width: 520px) {
  .auth-shell {
    width: min(100% - 24px, 1080px);
    padding: 18px 0;
    gap: 18px;
  }

  .auth-layout {
    grid-template-columns: 1fr;
  }

  .auth-panel {
    display: none;
  }

  .auth-card {
    padding: 20px 16px;
  }

  .auth-header h1 {
    font-size: 26px;
  }

  .dashboard-copy h1 {
    font-size: 25px;
  }

  .home-sub {
    margin-bottom: 18px;
  }

  .shell-icon-btn,
  .shell-text-btn {
    min-width: 36px;
  }

  .shell-text-btn {
    padding-left: 10px;
    padding-right: 10px;
  }

  .panel-row {
    grid-template-columns: 1fr;
    gap: 6px;
  }

  .exercise-question {
    grid-template-columns: 1fr;
  }

  .feynman-input-container {
    grid-template-columns: 1fr;
  }

  .feynman-input-btn {
    width: 100%;
  }

  .submission-meta {
    flex-direction: column;
  }

  .attachment-chip,
  .attachment-pending-item {
    align-items: flex-start;
    flex-direction: column;
  }

  .calendar-grid {
    gap: 4px;
  }

  .calendar-cell {
    min-height: 50px;
    padding: 5px;
  }

  .calendar-day-title,
  .calendar-day-progress {
    display: none;
  }

  .admin-analytics-toolbar,
  .admin-analytics-panel-head,
  .admin-analytics-filters {
    align-items: stretch;
    flex-direction: column;
  }

  .admin-analytics-filters .btn,
  .admin-analytics-filters select {
    width: 100%;
  }

  .admin-analytics-chart {
    gap: 5px;
  }
}

@media (max-width: 380px) {
  .shell {
    width: min(100% - 18px, 1180px);
  }

  .shell-brand-name {
    max-width: 5em;
  }

  .dashboard-hero,
  .lesson-header,
  .lesson-outline,
  .lesson-stage,
  .exercise-list,
  .feynman-brief {
    padding: 14px;
  }

  .dashboard-copy h1 {
    font-size: 23px;
  }

  .video-feedback-actions {
    grid-template-columns: repeat(2, minmax(0, 1fr));
  }

  .admin-analytics-stats {
    grid-template-columns: 1fr;
  }
}

/* ===== 学习概览仪表盘 ===== */
.home-overview {
  margin-top: 26px;
}

.overview-head {
  margin-bottom: 14px;
}

.overview-sub {
  color: var(--color-muted);
  font-size: 14px;
  margin-top: 2px;
}

.overview-stats {
  display: grid;
  grid-template-columns: repeat(6, minmax(0, 1fr));
  gap: 12px;
}

.overview-stat {
  display: flex;
  flex-direction: column;
  gap: 4px;
  border: 1px solid var(--color-border);
  border-radius: var(--radius);
  background: var(--color-surface);
  padding: 14px 16px;
  box-shadow: var(--shadow-soft);
}

.overview-stat-value {
  font-size: 26px;
  font-weight: 700;
  line-height: 1.1;
  color: var(--color-text);
}

.overview-stat-value small {
  font-size: 13px;
  font-weight: 500;
  color: var(--color-muted);
  margin-left: 3px;
}

.overview-stat-label {
  font-size: 13px;
  color: var(--color-muted);
}

.overview-block {
  margin-top: 22px;
}

.overview-block-title {
  font-size: 15px;
  font-weight: 600;
  margin-bottom: 12px;
  color: var(--color-text);
}

.overview-block-title small {
  font-size: 12px;
  font-weight: 400;
  color: var(--color-soft);
}

/* 里程碑 */
.overview-milestones {
  list-style: none;
  margin: 0;
  padding: 0;
  display: grid;
  grid-template-columns: repeat(auto-fill, minmax(150px, 1fr));
  gap: 10px;
}

.overview-milestone {
  display: flex;
  align-items: center;
  gap: 10px;
  border: 1px solid var(--color-border);
  border-radius: var(--radius);
  background: var(--color-panel);
  padding: 10px 12px;
  opacity: 0.7;
}

.overview-milestone.is-done {
  opacity: 1;
  border-color: var(--color-primary);
  background: var(--color-primary-soft);
}

.overview-milestone-mark {
  font-size: 18px;
  color: var(--color-soft);
}

.overview-milestone.is-done .overview-milestone-mark {
  color: var(--color-primary);
}

.overview-milestone-body {
  display: flex;
  flex-direction: column;
  min-width: 0;
}

.overview-milestone-body strong {
  font-size: 14px;
}

.overview-milestone-body small {
  font-size: 12px;
  color: var(--color-muted);
}

/* 打卡热力图 */
.heatmap-grid {
  display: flex;
  gap: 4px;
  overflow-x: auto;
  padding-bottom: 4px;
}

.heatmap-col {
  display: grid;
  grid-template-rows: repeat(7, 1fr);
  gap: 4px;
}

.heatmap-cell {
  width: 14px;
  height: 14px;
  border-radius: 3px;
  background: var(--color-panel-strong);
  border: 1px solid var(--color-border);
}

.heatmap-cell.is-done {
  background: var(--color-primary);
  border-color: var(--color-primary);
}

.heatmap-cell.is-today {
  outline: 2px solid var(--color-amber);
  outline-offset: 1px;
}

.heatmap-cell.is-future {
  background: transparent;
  border-color: transparent;
}

/* 待补缺口 */
.overview-weak-list {
  list-style: none;
  margin: 0;
  padding: 0;
  display: grid;
  gap: 10px;
}

.overview-weak-item {
  display: flex;
  gap: 10px;
  align-items: flex-start;
  border: 1px solid var(--color-border);
  border-radius: var(--radius);
  background: var(--color-surface);
  padding: 12px 14px;
}

.overview-weak-tag {
  flex: none;
  font-size: 12px;
  color: var(--color-amber);
  background: var(--color-amber-soft);
  border-radius: var(--radius-sm);
  padding: 3px 8px;
  white-space: nowrap;
}

.overview-weak-body {
  min-width: 0;
}

.overview-weak-point {
  font-size: 14px;
  color: var(--color-text);
  overflow-wrap: anywhere;
}

.overview-weak-issue {
  display: block;
  font-size: 12px;
  color: var(--color-muted);
  margin-top: 2px;
}

.overview-weak-meta {
  display: block;
  font-size: 12px;
  color: var(--color-soft);
  margin-top: 4px;
}

@media (max-width: 720px) {
  .overview-stats {
    grid-template-columns: repeat(3, minmax(0, 1fr));
  }
}

@media (max-width: 460px) {
  .overview-stats {
    grid-template-columns: repeat(2, minmax(0, 1fr));
  }
}

/* ===== 待补缺口标题栏 + 复习入口按钮 ===== */
.overview-block-bar {
  display: flex;
  align-items: center;
  justify-content: space-between;
  gap: 12px;
  margin-bottom: 12px;
}

.overview-block-bar .overview-block-title {
  margin-bottom: 0;
}

.btn-small {
  padding: 6px 12px;
  font-size: 13px;
  white-space: nowrap;
}

/* ===== 薄弱点复习弹层 ===== */
.weak-review-modal {
  position: fixed;
  inset: 0;
  z-index: 85;
  display: grid;
  place-items: center;
  padding: 20px;
}

.weak-review-backdrop {
  position: absolute;
  inset: 0;
  background: rgba(16, 20, 20, 0.54);
}

.weak-review-panel {
  position: relative;
  width: min(640px, 100%);
  max-height: calc(100vh - 40px);
  overflow-y: auto;
  display: flex;
  flex-direction: column;
  gap: 16px;
  border: 1px solid var(--color-border);
  border-radius: var(--radius);
  background: var(--color-surface);
  box-shadow: var(--shadow);
  padding: 22px;
}

.weak-review-head {
  display: flex;
  align-items: flex-start;
  justify-content: space-between;
  gap: 12px;
}

.weak-review-head h2 {
  font-size: 19px;
  margin-top: 2px;
}

.weak-review-head-right {
  display: flex;
  align-items: center;
  gap: 10px;
}

.weak-review-progress {
  font-size: 13px;
  color: var(--color-muted);
  white-space: nowrap;
}

.wr-card {
  display: flex;
  flex-direction: column;
  gap: 12px;
}

.wr-card-head {
  display: flex;
  align-items: center;
  gap: 10px;
  flex-wrap: wrap;
}

.wr-tag {
  font-size: 12px;
  color: var(--color-amber);
  background: var(--color-amber-soft);
  border-radius: var(--radius-sm);
  padding: 3px 8px;
}

.wr-meta {
  font-size: 12px;
  color: var(--color-soft);
}

.wr-point {
  font-size: 15px;
  font-weight: 600;
  color: var(--color-text);
  overflow-wrap: anywhere;
}

.wr-issue {
  font-size: 13px;
  color: var(--color-muted);
}

.wr-loading {
  font-size: 14px;
  color: var(--color-muted);
}

.wr-question {
  font-size: 15px;
  line-height: 1.6;
  color: var(--color-text);
  background: var(--color-panel);
  border: 1px solid var(--color-border);
  border-radius: var(--radius);
  padding: 14px 16px;
  overflow-wrap: anywhere;
}

.wr-hint {
  font-size: 13px;
  color: var(--color-muted);
}

.wr-actions {
  display: flex;
  justify-content: flex-end;
  gap: 10px;
}

.wr-feedback {
  display: flex;
  flex-direction: column;
  gap: 10px;
  border: 1px solid var(--color-border);
  border-radius: var(--radius);
  background: var(--color-panel);
  padding: 14px 16px;
}

.wr-feedback-head {
  display: flex;
  align-items: center;
  gap: 10px;
}

.wr-verdict {
  font-size: 13px;
  font-weight: 600;
  border-radius: var(--radius-sm);
  padding: 3px 10px;
}

.wr-verdict.is-correct {
  color: var(--color-success);
  background: var(--color-success-soft);
}

.wr-verdict.is-partial {
  color: var(--color-amber);
  background: var(--color-amber-soft);
}

.wr-verdict.is-incorrect {
  color: var(--color-error);
  background: var(--color-error-soft);
}

.wr-score {
  font-size: 13px;
  color: var(--color-muted);
}

.wr-summary {
  font-size: 14px;
  line-height: 1.6;
  color: var(--color-text);
}

.wr-improve strong,
.wr-suggested strong {
  font-size: 13px;
  color: var(--color-text);
}

.wr-improve ul {
  margin: 4px 0 0;
  padding-left: 18px;
  font-size: 13px;
  color: var(--color-muted);
}

.wr-suggested div {
  font-size: 13px;
  line-height: 1.6;
  color: var(--color-muted);
  margin-top: 4px;
}

.wr-schedule {
  font-size: 13px;
  color: var(--color-soft);
}

.wr-done {
  display: flex;
  flex-direction: column;
  align-items: center;
  gap: 16px;
  padding: 32px 12px;
  text-align: center;
}

.wr-done-msg {
  font-size: 16px;
  color: var(--color-text);
}