:root {
  color-scheme: light;
  --bg: #f4f7fb;
  --card: #ffffff;
  --card-soft: #eef5ff;
  --text: #132238;
  --muted: #607089;
  --primary: #1769e0;
  --primary-dark: #0b4fb3;
  --success: #0f9f6e;
  --warning: #d77908;
  --border: #dbe5f3;
  --shadow: 0 22px 60px rgba(24, 54, 91, 0.12);
}

* {
  box-sizing: border-box;
}

body {
  margin: 0;
  min-height: 100vh;
  background:
    radial-gradient(circle at top left, rgba(23, 105, 224, 0.16), transparent 32rem),
    linear-gradient(135deg, #f8fbff 0%, var(--bg) 100%);
  color: var(--text);
  font-family: Inter, "PingFang SC", "Microsoft YaHei", Arial, sans-serif;
}

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

.hidden {
  display: none !important;
}

.login-view {
  position: relative;
  overflow: hidden;
  display: grid;
  min-height: 100vh;
  place-items: center;
  padding: 24px;
  background:
    linear-gradient(120deg, rgba(8, 24, 46, 0.92), rgba(11, 79, 179, 0.78)),
    radial-gradient(circle at 20% 20%, rgba(85, 214, 190, 0.34), transparent 28rem),
    radial-gradient(circle at 80% 10%, rgba(98, 169, 255, 0.24), transparent 28rem),
    #07172b;
}

.login-view::before {
  content: "";
  position: absolute;
  inset: 0;
  background-image:
    linear-gradient(rgba(255, 255, 255, 0.05) 1px, transparent 1px),
    linear-gradient(90deg, rgba(255, 255, 255, 0.05) 1px, transparent 1px);
  background-size: 56px 56px;
  mask-image: radial-gradient(circle at center, #000 0%, transparent 72%);
}

.login-ambient {
  position: absolute;
  border-radius: 999px;
  filter: blur(2px);
  opacity: 0.72;
  animation: floatPulse 8s ease-in-out infinite;
}

.ambient-one {
  width: 320px;
  height: 320px;
  top: 9%;
  left: 9%;
  background: radial-gradient(circle, rgba(85, 214, 190, 0.34), transparent 65%);
}

.ambient-two {
  width: 420px;
  height: 420px;
  right: 6%;
  bottom: 7%;
  background: radial-gradient(circle, rgba(98, 169, 255, 0.28), transparent 65%);
  animation-delay: -2s;
}

.ambient-three {
  width: 180px;
  height: 180px;
  right: 24%;
  top: 18%;
  background: radial-gradient(circle, rgba(255, 242, 221, 0.22), transparent 62%);
  animation-delay: -4s;
}

.login-orbit {
  position: absolute;
  width: min(680px, 78vw);
  aspect-ratio: 1;
  border: 1px solid rgba(255, 255, 255, 0.12);
  border-radius: 999px;
  animation: slowRotate 26s linear infinite;
}

.login-orbit span {
  position: absolute;
  display: block;
  width: 10px;
  height: 10px;
  border-radius: 999px;
  background: #55d6be;
  box-shadow: 0 0 22px rgba(85, 214, 190, 0.9);
}

.login-orbit span:nth-child(1) {
  top: 7%;
  left: 48%;
}

.login-orbit span:nth-child(2) {
  right: 11%;
  top: 62%;
  background: #62a9ff;
}

.login-orbit span:nth-child(3) {
  left: 13%;
  bottom: 22%;
  background: #fff2dd;
}

@keyframes floatPulse {
  0%,
  100% {
    transform: translate3d(0, 0, 0) scale(1);
  }

  50% {
    transform: translate3d(18px, -16px, 0) scale(1.08);
  }
}

@keyframes slowRotate {
  to {
    transform: rotate(360deg);
  }
}

.login-card {
  position: relative;
  z-index: 1;
  width: min(460px, 100%);
  padding: 34px;
  border: 1px solid rgba(255, 255, 255, 0.26);
  border-radius: 30px;
  background: linear-gradient(180deg, rgba(255, 255, 255, 0.95), rgba(246, 250, 255, 0.9));
  box-shadow: 0 28px 90px rgba(1, 10, 28, 0.38);
  backdrop-filter: blur(18px);
}

.login-card::before {
  content: "";
  position: absolute;
  inset: 0;
  border-radius: inherit;
  pointer-events: none;
  background: linear-gradient(135deg, rgba(255, 255, 255, 0.68), transparent 38%);
}

.login-badge {
  position: relative;
  z-index: 1;
  display: inline-flex;
  margin-bottom: 18px;
  padding: 7px 12px;
  border: 1px solid rgba(23, 105, 224, 0.18);
  border-radius: 999px;
  background: rgba(238, 245, 255, 0.9);
  color: var(--primary-dark);
  font-size: 12px;
  font-weight: 900;
  letter-spacing: 0.08em;
  text-transform: uppercase;
}

.login-brand {
  position: relative;
  z-index: 1;
  margin-bottom: 28px;
  color: var(--text);
}

.login-brand small {
  color: var(--muted);
}

.login-form {
  position: relative;
  z-index: 1;
  display: grid;
  gap: 16px;
}

.login-form input {
  width: 100%;
  padding: 13px 14px;
  border: 1px solid var(--border);
  border-radius: 16px;
  background: #fbfdff;
  color: var(--text);
}

.form-error {
  min-height: 22px;
  margin: 0;
  color: #c0342b;
  font-size: 14px;
}

.login-value-grid {
  position: relative;
  z-index: 1;
  display: grid;
  grid-template-columns: repeat(3, minmax(0, 1fr));
  gap: 10px;
  margin-top: 18px;
}

.login-value-grid div {
  padding: 12px;
  border: 1px solid rgba(219, 229, 243, 0.88);
  border-radius: 16px;
  background: rgba(255, 255, 255, 0.78);
}

.login-value-grid strong,
.login-value-grid span {
  display: block;
}

.login-value-grid strong {
  color: var(--primary-dark);
  font-size: 13px;
}

.login-value-grid span {
  margin-top: 5px;
  color: var(--muted);
  font-size: 12px;
  line-height: 1.45;
}

.app-shell {
  display: grid;
  grid-template-columns: 280px minmax(0, 1fr);
  min-height: 100vh;
}

.sidebar {
  position: sticky;
  top: 0;
  height: 100vh;
  padding: 28px;
  background: #0f223a;
  color: #fff;
}

.brand,
.status-card,
.panel-header,
.hero,
.hero-metrics,
.timeline {
  display: flex;
}

.brand {
  align-items: center;
  gap: 14px;
  margin-bottom: 36px;
}

.brand-mark {
  display: grid;
  width: 48px;
  height: 48px;
  place-items: center;
  border-radius: 16px;
  background: linear-gradient(135deg, #55d6be, #62a9ff);
  color: #08192d;
  font-size: 24px;
  font-weight: 800;
}

.brand strong,
.brand small,
.status-card strong,
.status-card small {
  display: block;
}

.brand small,
.status-card small {
  margin-top: 4px;
  color: rgba(255, 255, 255, 0.68);
}

.role-switcher {
  display: grid;
  gap: 12px;
}

.user-card {
  display: flex;
  align-items: center;
  gap: 12px;
  margin-bottom: 22px;
  padding: 14px;
  border: 1px solid rgba(255, 255, 255, 0.1);
  border-radius: 18px;
  background: rgba(255, 255, 255, 0.07);
}

.user-card > span {
  display: grid;
  width: 42px;
  height: 42px;
  place-items: center;
  border-radius: 999px;
  background: #fff;
  color: #0f223a;
  font-weight: 800;
}

.user-card strong,
.user-card small {
  display: block;
}

.user-card small {
  margin-top: 4px;
  color: rgba(255, 255, 255, 0.68);
}

.role-button {
  width: 100%;
  padding: 14px 16px;
  border: 1px solid rgba(255, 255, 255, 0.12);
  border-radius: 16px;
  background: rgba(255, 255, 255, 0.06);
  color: rgba(255, 255, 255, 0.84);
  cursor: pointer;
  text-align: left;
}

.role-button.active,
.role-button:hover {
  background: #fff;
  color: #0f223a;
}

.status-card {
  align-items: center;
  gap: 12px;
  margin-top: 28px;
  padding: 16px;
  border: 1px solid rgba(255, 255, 255, 0.1);
  border-radius: 18px;
  background: rgba(255, 255, 255, 0.07);
}

.logout-button {
  width: 100%;
  margin-top: 14px;
  padding: 12px 14px;
  border: 1px solid rgba(255, 255, 255, 0.16);
  border-radius: 16px;
  background: transparent;
  color: rgba(255, 255, 255, 0.86);
  cursor: pointer;
  font-weight: 700;
}

.logout-button:hover {
  background: rgba(255, 255, 255, 0.1);
}

.status-dot {
  width: 10px;
  height: 10px;
  border-radius: 999px;
  background: var(--warning);
  box-shadow: 0 0 0 6px rgba(215, 121, 8, 0.16);
}

.ai-ready .status-dot {
  background: var(--success);
  box-shadow: 0 0 0 6px rgba(15, 159, 110, 0.18);
}

main {
  padding: 34px;
}

.hero {
  align-items: center;
  justify-content: space-between;
  gap: 28px;
  margin-bottom: 24px;
  padding: 22px 24px;
  border-radius: 28px;
  background: linear-gradient(135deg, #ffffff 0%, #e9f3ff 100%);
  box-shadow: var(--shadow);
}

.eyebrow {
  margin: 0 0 8px;
  color: var(--primary);
  font-size: 12px;
  font-weight: 800;
  letter-spacing: 0.12em;
  text-transform: uppercase;
}

h1,
h2,
h3,
p {
  margin-top: 0;
}

h1 {
  margin-bottom: 12px;
  font-size: clamp(28px, 4vw, 46px);
  line-height: 1.1;
}

h2 {
  margin-bottom: 0;
  font-size: 22px;
}

h3 {
  margin-bottom: 10px;
  font-size: 18px;
}

.hero p {
  max-width: 720px;
  margin-bottom: 0;
  color: var(--muted);
}

.hero-metrics {
  gap: 12px;
  min-width: 330px;
}

.hero-metrics div,
.metric-link {
  flex: 1;
  padding: 18px;
  border: 0;
  border-radius: 20px;
  background: rgba(255, 255, 255, 0.74);
  color: inherit;
  cursor: pointer;
  text-align: center;
}

.metric-link:hover,
.metric-link.active {
  background: #ffffff;
  box-shadow: inset 0 0 0 2px rgba(23, 105, 224, 0.22);
}

.hero-metrics strong,
.hero-metrics span {
  display: block;
}

.hero-metrics strong {
  color: var(--primary);
  font-size: 24px;
  text-decoration: underline;
  text-underline-offset: 4px;
}

.hero-metrics span {
  margin-top: 6px;
  color: var(--muted);
  font-size: 13px;
}

.dashboard-grid {
  display: grid;
  grid-template-columns: minmax(0, 1fr) minmax(420px, 0.9fr);
  gap: 24px;
  align-items: start;
}

.panel {
  margin-bottom: 24px;
  padding: 20px;
  border: 1px solid var(--border);
  border-radius: 26px;
  background: rgba(255, 255, 255, 0.88);
  box-shadow: var(--shadow);
}

.panel-header {
  align-items: center;
  justify-content: space-between;
  gap: 16px;
  margin-bottom: 20px;
}

.badge {
  display: inline-flex;
  align-items: center;
  justify-content: center;
  min-width: 70px;
  padding: 8px 12px;
  border-radius: 999px;
  background: var(--card-soft);
  color: var(--primary-dark);
  font-size: 13px;
  font-weight: 700;
}

.badge.warning {
  background: #fff2dd;
  color: var(--warning);
}

.feature-grid {
  display: grid;
  grid-template-columns: repeat(2, minmax(0, 1fr));
  gap: 16px;
}

.feature-card {
  min-height: 164px;
  padding: 20px;
  border: 1px solid var(--border);
  border-radius: 22px;
  background: var(--card);
}

.feature-card span {
  display: inline-block;
  margin-bottom: 16px;
  padding: 6px 10px;
  border-radius: 999px;
  background: #ecf8f4;
  color: var(--success);
  font-size: 12px;
  font-weight: 800;
}

.feature-card p {
  color: var(--muted);
  line-height: 1.7;
}

.module-content {
  display: grid;
  gap: 12px;
  margin-top: 18px;
}

.module-row {
  display: grid;
  gap: 6px;
  padding: 16px;
  border: 1px solid var(--border);
  border-radius: 18px;
  background: #f9fbff;
}

.module-row span {
  color: var(--muted);
  line-height: 1.6;
}

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

.ai-form .context-field,
.ai-form .prompt-field,
.ai-form .ai-suggestions,
.ai-form button[type="submit"] {
  width: 100%;
}

.ai-suggestions {
  display: grid;
  grid-template-columns: repeat(3, minmax(0, 1fr));
  gap: 10px;
}

.ai-suggestion {
  display: grid;
  gap: 5px;
  padding: 11px 12px;
  border: 1px solid var(--border);
  border-radius: 14px;
  background: #fff;
  color: var(--text);
  cursor: pointer;
  text-align: left;
}

.ai-suggestion:hover,
.ai-suggestion.active {
  border-color: rgba(23, 105, 224, 0.45);
  background: #eef5ff;
}

.ai-suggestion strong {
  color: var(--primary-dark);
  font-size: 13px;
}

.ai-suggestion span {
  display: -webkit-box;
  overflow: hidden;
  color: var(--muted);
  font-size: 12px;
  line-height: 1.45;
  -webkit-line-clamp: 2;
  -webkit-box-orient: vertical;
}

label {
  display: grid;
  gap: 8px;
  color: var(--muted);
  font-size: 14px;
  font-weight: 700;
}

select,
textarea {
  width: 100%;
  border: 1px solid var(--border);
  border-radius: 16px;
  background: #fbfdff;
  color: var(--text);
}

.tab-panel input,
.tab-panel select,
.tab-panel textarea {
  width: 100%;
  padding: 12px 14px;
  border: 1px solid var(--border);
  border-radius: 14px;
  background: #fbfdff;
  color: var(--text);
}

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

.tab-panel > p {
  color: var(--muted);
  line-height: 1.7;
}

.table-wrap {
  overflow-x: auto;
  border: 1px solid var(--border);
  border-radius: 18px;
  background: #fff;
}

.data-table {
  width: 100%;
  border-collapse: collapse;
  min-width: 720px;
}

.data-table th,
.data-table td {
  padding: 13px 14px;
  border-bottom: 1px solid var(--border);
  text-align: left;
  vertical-align: middle;
}

.data-table th {
  background: #f3f7fd;
  color: var(--muted);
  font-size: 13px;
}

.data-table tr:last-child td {
  border-bottom: 0;
}

.mini-button {
  display: inline-flex;
  align-items: center;
  justify-content: center;
  gap: 6px;
  margin: 2px;
  padding: 8px 12px;
  border: 0;
  border-radius: 12px;
  background: var(--primary);
  color: #fff;
  cursor: pointer;
  font-size: 13px;
  font-weight: 800;
}

.mini-button.ghost {
  border: 1px solid var(--border);
  background: #fff;
  color: var(--primary-dark);
}

.text-link {
  padding: 0;
  border: 0;
  background: transparent;
  color: var(--primary);
  cursor: pointer;
  font: inherit;
  font-weight: 800;
  text-align: left;
  text-decoration: underline;
  text-underline-offset: 4px;
}

.text-link:hover {
  color: var(--primary-dark);
}

.notice {
  padding: 13px 14px;
  border-radius: 16px;
  background: #eef8f4;
  color: #0c7252;
  line-height: 1.6;
}

.notice.warning {
  background: #fff2dd;
  color: var(--warning);
}

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

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

.progress-list div > span {
  color: var(--muted);
  font-weight: 700;
}

progress {
  width: 100%;
  height: 12px;
  overflow: hidden;
  border: 0;
  border-radius: 999px;
}

progress::-webkit-progress-bar {
  background: #e8eef7;
}

progress::-webkit-progress-value {
  background: linear-gradient(90deg, var(--primary), #55d6be);
}

.insight-grid,
.form-grid {
  display: grid;
  grid-template-columns: repeat(3, minmax(0, 1fr));
  gap: 14px;
}

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

.insight-grid > div,
.paper-preview {
  padding: 16px;
  border: 1px solid var(--border);
  border-radius: 18px;
  background: #f9fbff;
}

.insight-grid p,
.paper-preview p {
  margin-bottom: 0;
  color: var(--muted);
  line-height: 1.6;
}

.paper-editor {
  display: grid;
  gap: 16px;
  padding: 18px;
  border: 1px solid var(--border);
  border-radius: 20px;
  background: #f9fbff;
}

.paper-editor-header,
.paper-actions {
  display: flex;
  align-items: center;
  justify-content: space-between;
  gap: 12px;
}

.paper-editor-header span {
  display: block;
  margin-top: 4px;
  color: var(--muted);
  line-height: 1.5;
}

.student-chips {
  display: grid;
  gap: 10px;
  padding: 14px;
  border: 1px dashed #bfd0ea;
  border-radius: 16px;
  background: #fff;
}

.student-chips div {
  display: flex;
  flex-wrap: wrap;
  gap: 8px;
}

.student-chips span {
  padding: 6px 10px;
  border-radius: 999px;
  background: #eef5ff;
  color: var(--primary-dark);
  font-size: 13px;
  font-weight: 800;
}

.question-editor-list {
  display: grid;
  gap: 14px;
}

.question-editor {
  display: grid;
  gap: 12px;
  padding: 16px;
  border: 1px solid var(--border);
  border-radius: 18px;
  background: #fff;
}

.big-number {
  margin-top: 10px;
  color: var(--primary);
  font-size: 30px;
  font-weight: 900;
}

.big-number.danger {
  color: #c0342b;
}

.score-input {
  max-width: 90px;
}

.check-row {
  display: flex;
  grid-template-columns: auto 1fr;
  align-items: center;
  gap: 10px;
  padding: 12px 14px;
  border: 1px solid var(--border);
  border-radius: 14px;
  background: #fff;
}

.check-row input {
  width: auto;
}

select {
  padding: 12px 14px;
}

textarea {
  resize: vertical;
  padding: 14px;
  line-height: 1.6;
}

button[type="submit"] {
  padding: 14px 18px;
  border: 0;
  border-radius: 16px;
  background: var(--primary);
  color: #fff;
  cursor: pointer;
  font-weight: 800;
}

button[type="submit"]:disabled {
  cursor: wait;
  opacity: 0.72;
}

.ai-output {
  min-height: 220px;
  max-height: 420px;
  margin: 16px 0 0;
  padding: 18px;
  overflow: auto;
  border-radius: 18px;
  background: #f8fbff;
  color: var(--text);
  line-height: 1.7;
}

.rich-output {
  border: 1px solid var(--border);
}

.ai-readable {
  display: grid;
  gap: 10px;
}

.ai-readable h3,
.ai-readable h4 {
  margin: 6px 0 2px;
  color: var(--primary-dark);
}

.ai-readable p {
  margin: 0;
  padding: 10px 12px;
  border-radius: 12px;
  background: #fff;
  line-height: 1.75;
}

.ai-readable ul {
  display: grid;
  gap: 8px;
  margin: 0;
  padding: 0;
  list-style: none;
}

.ai-readable li {
  position: relative;
  padding: 10px 12px 10px 32px;
  border-radius: 12px;
  background: #fff;
  line-height: 1.7;
}

.ai-readable li::before {
  content: "";
  position: absolute;
  top: 18px;
  left: 14px;
  width: 7px;
  height: 7px;
  border-radius: 999px;
  background: var(--primary);
}

.ai-callout-line {
  border-left: 4px solid var(--primary);
  background: #eef5ff !important;
}

.ai-meta {
  display: flex;
  flex-wrap: wrap;
  gap: 10px;
  margin-top: 14px;
  padding-top: 12px;
  border-top: 1px solid var(--border);
}

.ai-meta span {
  padding: 6px 10px;
  border-radius: 999px;
  background: #eef8f4;
  color: #0c7252;
  font-size: 13px;
  font-weight: 800;
}

.reader-modal {
  position: fixed;
  inset: 0;
  z-index: 20;
  display: grid;
  place-items: center;
  padding: 22px;
  background: rgba(9, 22, 38, 0.58);
}

.reader-dialog {
  display: grid;
  grid-template-rows: auto minmax(0, 1fr) auto;
  width: min(1120px, 96vw);
  height: min(780px, 92vh);
  border-radius: 26px;
  background: #fff;
  box-shadow: 0 28px 80px rgba(4, 15, 31, 0.3);
  overflow: hidden;
}

.assignment-dialog {
  display: grid;
  grid-template-rows: auto minmax(0, 1fr);
  width: min(780px, 94vw);
  max-height: min(760px, 90vh);
  border-radius: 26px;
  background: #fff;
  box-shadow: 0 28px 80px rgba(4, 15, 31, 0.3);
  overflow: hidden;
}

.assignment-content {
  display: grid;
  gap: 16px;
  padding: 22px;
  overflow: auto;
  background: #f8fbff;
}

.assignment-section {
  padding: 18px;
  border: 1px solid var(--border);
  border-radius: 18px;
  background: #fff;
}

.assignment-section h3 {
  margin-bottom: 12px;
}

.assignment-section p,
.assignment-section li {
  color: var(--muted);
  line-height: 1.8;
}

.assignment-section ul {
  display: grid;
  gap: 8px;
  margin: 0;
  padding-left: 20px;
}

.assignment-actions {
  display: flex;
  flex-wrap: wrap;
  gap: 10px;
  justify-content: flex-end;
  padding: 4px 0;
}

.reader-header,
.reader-footer {
  display: flex;
  align-items: center;
  justify-content: space-between;
  gap: 14px;
  padding: 18px 22px;
  border-bottom: 1px solid var(--border);
}

.reader-footer {
  border-top: 1px solid var(--border);
  border-bottom: 0;
}

.reader-header h2 {
  margin-bottom: 4px;
}

.reader-header span,
.reader-footer span {
  color: var(--muted);
}

.icon-button {
  width: 42px;
  height: 42px;
  border: 0;
  border-radius: 999px;
  background: #eef5ff;
  color: var(--primary-dark);
  cursor: pointer;
  font-size: 28px;
  line-height: 1;
}

.reader-body {
  display: grid;
  grid-template-columns: 250px minmax(0, 1fr);
  min-height: 0;
}

.reader-outline {
  display: grid;
  align-content: start;
  gap: 10px;
  padding: 18px;
  overflow: auto;
  border-right: 1px solid var(--border);
  background: #f8fbff;
}

.reader-outline-title {
  padding: 4px 2px 8px;
  color: var(--primary-dark);
  font-size: 12px;
  font-weight: 900;
  letter-spacing: 0.08em;
  text-transform: uppercase;
}

.reader-outline button {
  display: flex;
  align-items: center;
  gap: 10px;
  width: 100%;
  padding: 12px;
  border: 1px solid var(--border);
  border-radius: 14px;
  background: #fff;
  color: var(--text);
  cursor: pointer;
  text-align: left;
}

.reader-outline button.active {
  border-color: rgba(23, 105, 224, 0.45);
  background: #eef5ff;
}

.reader-outline strong {
  display: grid;
  width: 28px;
  height: 28px;
  place-items: center;
  border-radius: 999px;
  background: var(--primary);
  color: #fff;
  font-size: 13px;
}

.reader-document {
  overflow: auto;
  padding: 24px;
  background: #dfe7f2;
}

.mock-pdf-toolbar {
  display: flex;
  flex-wrap: wrap;
  gap: 10px;
  margin-bottom: 16px;
  padding: 10px 14px;
  border-radius: 14px;
  background: #0f223a;
  color: #dff7ff;
}

.mock-pdf-page {
  min-height: 520px;
  max-width: 760px;
  margin: 0 auto;
  padding: 54px;
  border-radius: 8px;
  background: #fff;
  box-shadow: 0 18px 46px rgba(24, 54, 91, 0.2);
}

.mock-pdf-page h2 {
  margin-bottom: 22px;
  font-size: 30px;
}

.mock-pdf-page p {
  color: var(--text);
  font-size: 18px;
  line-height: 2;
}

.selectable-material {
  cursor: text;
  user-select: text;
}

.pdf-reader-display {
  display: grid;
  gap: 14px;
  margin-top: 18px;
  padding: 26px;
  border: 1px solid rgba(23, 105, 224, 0.16);
  border-radius: 18px;
  background:
    linear-gradient(180deg, rgba(248, 251, 255, 0.9), rgba(255, 255, 255, 0.96)),
    #fff;
  box-shadow: inset 0 0 0 1px rgba(255, 255, 255, 0.8);
}

.pdf-reader-display > strong {
  color: var(--primary-dark);
  font-size: 12px;
  font-weight: 900;
  letter-spacing: 0.08em;
}

.pdf-reader-display p {
  margin: 0;
  color: var(--text);
  font-size: 18px;
  line-height: 2;
}

.pdf-reader-shell {
  position: relative;
  display: grid;
  gap: 14px;
}

.pdf-selection-layer {
  position: absolute;
  top: 18px;
  right: 18px;
  z-index: 3;
  width: min(360px, 42%);
  max-height: 260px;
  overflow: auto;
  padding: 14px 16px;
  border: 1px solid rgba(23, 105, 224, 0.24);
  border-radius: 16px;
  background: rgba(248, 251, 255, 0.96);
  box-shadow: 0 16px 44px rgba(24, 54, 91, 0.18);
  backdrop-filter: blur(12px);
}

.pdf-selection-layer strong {
  display: block;
  margin-bottom: 8px;
  color: var(--primary-dark);
  font-size: 12px;
  font-weight: 900;
  letter-spacing: 0.06em;
}

.pdf-selection-layer p {
  margin: 0;
  color: var(--text);
  font-size: 16px;
  line-height: 1.9;
}

.uploaded-material-frame {
  width: 100%;
  min-height: 520px;
  margin-top: 22px;
  border: 1px solid var(--border);
  border-radius: 14px;
  background: #fff;
}

.pdf-preview-frame {
  min-height: min(72vh, 760px);
}

.uploaded-material-card {
  display: grid;
  gap: 10px;
  margin-top: 22px;
  padding: 18px;
  border: 1px dashed #bfd0ea;
  border-radius: 18px;
  background: #f8fbff;
}

.uploaded-material-card.compact {
  margin-top: 14px;
  padding: 14px;
}

.uploaded-material-card strong,
.uploaded-material-card span,
.uploaded-material-card a {
  display: block;
}

.uploaded-material-card span {
  color: var(--muted);
  line-height: 1.6;
}

.uploaded-material-card a {
  color: var(--primary);
  font-weight: 800;
}

.explain-popover {
  position: absolute;
  z-index: 60;
  width: min(360px, calc(100vw - 32px));
  padding: 14px;
  border: 1px solid rgba(23, 105, 224, 0.22);
  border-radius: 18px;
  background: rgba(255, 255, 255, 0.96);
  box-shadow: 0 22px 70px rgba(15, 34, 58, 0.24);
  backdrop-filter: blur(14px);
}

.explain-popover-header {
  display: flex;
  align-items: center;
  justify-content: space-between;
  gap: 12px;
}

.explain-popover-title {
  color: var(--primary);
  font-size: 12px;
  font-weight: 900;
  letter-spacing: 0.08em;
  text-transform: uppercase;
}

.explain-popover-close {
  display: inline-grid;
  width: 28px;
  height: 28px;
  place-items: center;
  border: 0;
  border-radius: 999px;
  background: #eef5ff;
  color: var(--primary-dark);
  cursor: pointer;
  font-size: 18px;
  font-weight: 900;
  line-height: 1;
}

.explain-popover-term {
  margin: 8px 0 10px;
  padding: 8px 10px;
  border-radius: 12px;
  background: #eef5ff;
  color: var(--primary-dark);
  font-weight: 900;
  line-height: 1.5;
}

.explain-popover-body {
  display: grid;
  gap: 8px;
  max-height: 260px;
  overflow: auto;
  color: var(--text);
  font-size: 14px;
  line-height: 1.7;
}

.explain-popover-loading {
  color: var(--muted);
}

.explain-popover-body p,
.explain-popover-body li {
  padding: 0;
  background: transparent;
}

.pdf-note {
  margin-top: 34px;
  padding: 14px;
  border-radius: 14px;
  background: #eef8f4;
  color: #0c7252;
}

.timeline {
  gap: 14px;
}

.timeline div {
  flex: 1;
  padding: 18px;
  border: 1px solid var(--border);
  border-radius: 20px;
  background: linear-gradient(180deg, #fff, #f8fbff);
}

.timeline strong,
.timeline span {
  display: block;
}

.timeline span {
  margin-top: 8px;
  color: var(--muted);
  line-height: 1.6;
}

@media (max-width: 1100px) {
  .app-shell,
  .dashboard-grid {
    grid-template-columns: 1fr;
  }

  .sidebar {
    position: static;
    height: auto;
  }

  .hero,
  .hero-metrics,
  .timeline {
    flex-direction: column;
  }

  .hero-metrics {
    min-width: 100%;
    width: 100%;
  }
}

@media (max-width: 680px) {
  main,
  .sidebar {
    padding: 18px;
  }

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