:root {
  --bg: #071018;
  --bg-2: #0d1720;
  --surface: rgba(14, 22, 31, 0.92);
  --surface-2: rgba(19, 29, 42, 0.96);
  --surface-3: rgba(24, 37, 54, 0.96);
  --border: rgba(255, 255, 255, 0.08);
  --border-strong: rgba(244, 180, 0, 0.32);
  --text: #edf2f7;
  --muted: #91a0b3;
  --accent: #f4b400;
  --accent-2: #ef6c24;
  --green: #41d492;
  --red: #f36c6c;
  --blue: #75a8ff;
  --shadow: 0 24px 70px rgba(0, 0, 0, 0.34);
  --radius-xl: 28px;
  --radius-lg: 20px;
  --radius-md: 16px;
  --radius-sm: 12px;
}

* {
  box-sizing: border-box;
  margin: 0;
  padding: 0;
}

html {
  scroll-behavior: smooth;
}

body {
  min-height: 100vh;
  background:
    radial-gradient(circle at top, rgba(244, 180, 0, 0.12), transparent 28%),
    radial-gradient(circle at right bottom, rgba(117, 168, 255, 0.14), transparent 26%),
    linear-gradient(180deg, #060d14 0%, #0b141d 100%);
  color: var(--text);
  font-family: "Sora", sans-serif;
  overflow-x: hidden;
}

body::before {
  content: "";
  position: fixed;
  inset: 0;
  pointer-events: none;
  background-image:
    linear-gradient(rgba(255, 255, 255, 0.025) 1px, transparent 1px),
    linear-gradient(90deg, rgba(255, 255, 255, 0.025) 1px, transparent 1px);
  background-size: 26px 26px;
  mask-image: radial-gradient(circle at center, black 45%, transparent 100%);
}

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

button,
input,
select {
  font: inherit;
}

button:focus-visible,
input:focus-visible,
select:focus-visible,
a:focus-visible {
  outline: 2px solid rgba(244, 180, 0, 0.9);
  outline-offset: 2px;
}

.app-shell {
  position: relative;
  z-index: 1;
  width: min(1220px, calc(100% - 2rem));
  margin: 0 auto;
  padding: 1.5rem 0 4rem;
}

.sr-only {
  position: absolute;
  width: 1px;
  height: 1px;
  padding: 0;
  margin: -1px;
  overflow: hidden;
  clip: rect(0, 0, 0, 0);
  white-space: nowrap;
  border: 0;
}

.skip-link {
  position: absolute;
  left: 1rem;
  top: 1rem;
  z-index: 30;
  padding: 0.75rem 1rem;
  border-radius: 999px;
  background: rgba(244, 180, 0, 0.96);
  color: #09111a;
  transform: translateY(-140%);
  transition: transform 0.2s ease;
}

.skip-link:focus {
  transform: translateY(0);
}

.toast-stack {
  position: fixed;
  right: 1rem;
  bottom: 1rem;
  z-index: 20;
  display: grid;
  gap: 0.75rem;
  width: min(360px, calc(100% - 2rem));
}

.toast {
  padding: 0.9rem 1rem;
  border-radius: var(--radius-md);
  background: rgba(16, 25, 36, 0.96);
  border: 1px solid rgba(244, 180, 0, 0.18);
  color: var(--text);
  box-shadow: var(--shadow);
  transform: translateY(0);
  transition: opacity 0.24s ease, transform 0.24s ease;
}

.toast.success {
  border-color: rgba(65, 212, 146, 0.24);
}

.toast.warning {
  border-color: rgba(243, 108, 108, 0.24);
}

.toast.info {
  border-color: rgba(117, 168, 255, 0.24);
}

.modal-shell {
  position: fixed;
  inset: 0;
  z-index: 18;
  display: flex;
  align-items: center;
  justify-content: center;
  padding: 1rem;
  background: rgba(3, 7, 11, 0.72);
  backdrop-filter: blur(10px);
}

.modal-card {
  width: min(560px, 100%);
  padding: 1.3rem;
  border-radius: var(--radius-lg);
  background: var(--surface-2);
  border: 1px solid var(--border);
  box-shadow: var(--shadow);
}

.welcome-steps {
  display: grid;
  gap: 0.7rem;
  margin: 1rem 0 1.2rem;
}

.welcome-step {
  padding: 0.85rem 1rem;
  border-radius: var(--radius-md);
  background: rgba(255, 255, 255, 0.035);
  color: #dce4ee;
  line-height: 1.7;
}

.hero,
.panel,
.surface-card,
.nav-tab,
.diagram-shell,
.flashcard,
.quiz-option,
.practice-card,
.checklist-item,
.stat-pill {
  border: 1px solid var(--border);
  box-shadow: var(--shadow);
}

.hero {
  position: relative;
  padding: 1.6rem;
  border-radius: var(--radius-xl);
  background:
    linear-gradient(135deg, rgba(244, 180, 0, 0.1), transparent 34%),
    linear-gradient(180deg, rgba(255, 255, 255, 0.04), transparent),
    var(--surface);
  overflow: hidden;
}

.hero-backdrop {
  position: absolute;
  inset: 0;
  background:
    radial-gradient(circle at 15% 20%, rgba(244, 180, 0, 0.12), transparent 18%),
    radial-gradient(circle at 80% 18%, rgba(239, 108, 36, 0.12), transparent 18%),
    radial-gradient(circle at 88% 78%, rgba(117, 168, 255, 0.1), transparent 22%);
  pointer-events: none;
}

.hero-head,
.hero-main {
  position: relative;
  z-index: 1;
}

.hero-head {
  display: flex;
  justify-content: space-between;
  gap: 1rem;
  margin-bottom: 1.4rem;
}

.hero-brand {
  display: flex;
  flex-direction: column;
  gap: 0.5rem;
}

.badge,
.hero-kicker,
.panel-kicker,
.section-kicker,
.surface-kicker,
.metric-label,
.spot-label,
.card-hint,
.counter,
.quiz-question-meta,
.note-chip {
  font-family: "Space Mono", monospace;
  text-transform: uppercase;
  letter-spacing: 0.12em;
}

.badge {
  display: inline-flex;
  align-items: center;
  gap: 0.5rem;
  width: fit-content;
  padding: 0.42rem 0.9rem;
  border-radius: 999px;
  background: rgba(244, 180, 0, 0.14);
  color: var(--accent);
  border: 1px solid rgba(244, 180, 0, 0.24);
  font-size: 0.72rem;
}

.hero-kicker {
  color: var(--muted);
  font-size: 0.7rem;
}

.hero-actions,
.lang-switcher,
.section-actions,
.spotlight-actions,
.resource-actions,
.control-row {
  display: flex;
  gap: 0.75rem;
  flex-wrap: wrap;
}

.lang-switcher {
  padding: 0.3rem;
  background: rgba(255, 255, 255, 0.05);
  border-radius: 999px;
  border: 1px solid var(--border);
}

.lang-btn,
.icon-btn,
.action-btn,
.nav-tab,
.quiz-option,
.checklist-item,
.diagram-chip {
  transition: 0.2s ease;
}

.lang-btn {
  min-width: 54px;
  border: none;
  background: transparent;
  color: var(--muted);
  padding: 0.55rem 0.9rem;
  border-radius: 999px;
  cursor: pointer;
}

.lang-btn.active,
.lang-btn:hover {
  background: var(--accent);
  color: #211300;
}

.icon-btn,
.action-btn {
  border-radius: var(--radius-sm);
  border: 1px solid rgba(244, 180, 0, 0.2);
  background: linear-gradient(180deg, rgba(244, 180, 0, 0.18), rgba(239, 108, 36, 0.12));
  color: var(--text);
  cursor: pointer;
}

.hidden {
  display: none !important;
}

.icon-btn {
  min-width: 140px;
  padding: 0.85rem 1rem;
}

.ghost-btn {
  background: rgba(255, 255, 255, 0.03);
  border-color: var(--border);
}

.icon-btn.danger {
  border-color: rgba(243, 108, 108, 0.2);
  background: linear-gradient(180deg, rgba(243, 108, 108, 0.18), rgba(119, 20, 20, 0.08));
}

.action-btn {
  display: inline-flex;
  justify-content: center;
  align-items: center;
  min-height: 44px;
  padding: 0.82rem 1.15rem;
}

.action-btn.ghost {
  background: rgba(255, 255, 255, 0.03);
  border-color: var(--border);
}

.icon-btn:hover,
.action-btn:hover,
.nav-tab:hover,
.diagram-chip:hover {
  transform: translateY(-1px);
  border-color: var(--border-strong);
}

.hero-main {
  display: grid;
  grid-template-columns: minmax(0, 1.35fr) minmax(360px, 0.9fr);
  gap: 1rem;
}

.hero-copy {
  padding-right: 1rem;
}

.hero-title {
  display: flex;
  flex-wrap: wrap;
  gap: 0.35rem;
  align-items: baseline;
  font-size: clamp(2.5rem, 6vw, 5rem);
  font-weight: 800;
  line-height: 0.98;
  letter-spacing: -0.07em;
}

.accent {
  color: var(--accent);
}

.subtitle,
.panel-text,
.section-copy,
.surface-copy,
.surface-note,
.section-note,
.result-copy {
  color: var(--muted);
  line-height: 1.75;
}

.subtitle {
  max-width: 720px;
  margin-top: 0.9rem;
}

.search-bar {
  display: flex;
  gap: 0.8rem;
  align-items: center;
  margin-top: 1.4rem;
}

.topic-filter-bar {
  display: flex;
  gap: 0.6rem;
  flex-wrap: wrap;
  margin-top: 1rem;
}

.search-wrap {
  flex: 1;
  display: flex;
  align-items: center;
  gap: 0.7rem;
  padding: 0.95rem 1rem;
  border-radius: var(--radius-md);
  border: 1px solid var(--border);
  background: rgba(255, 255, 255, 0.04);
}

.search-icon {
  color: var(--accent);
}

.search-wrap input {
  width: 100%;
  border: none;
  outline: none;
  background: transparent;
  color: var(--text);
}

.hero-notes {
  display: flex;
  gap: 0.6rem;
  flex-wrap: wrap;
  margin-top: 1rem;
}

.status-bar {
  display: flex;
  gap: 0.6rem;
  flex-wrap: wrap;
  margin-top: 0.85rem;
}

.note-chip {
  padding: 0.52rem 0.7rem;
  border-radius: 999px;
  font-size: 0.64rem;
  color: var(--muted);
  background: rgba(255, 255, 255, 0.04);
  border: 1px solid rgba(255, 255, 255, 0.05);
}

.status-chip {
  display: inline-flex;
  align-items: center;
  justify-content: center;
  min-height: 38px;
  padding: 0.55rem 0.8rem;
  border-radius: 999px;
  border: 1px solid rgba(255, 255, 255, 0.05);
  background: rgba(255, 255, 255, 0.04);
  color: var(--muted);
  font-family: "Space Mono", monospace;
  font-size: 0.68rem;
  letter-spacing: 0.08em;
  text-transform: uppercase;
}

.status-chip.online {
  color: var(--green);
  border-color: rgba(65, 212, 146, 0.18);
}

.status-chip.offline {
  color: var(--accent-2);
  border-color: rgba(239, 108, 36, 0.2);
}

.status-chip.action {
  cursor: pointer;
  color: var(--blue);
  border-color: rgba(117, 168, 255, 0.18);
}

.hero-panels {
  display: grid;
  gap: 1rem;
}

.panel,
.surface-card {
  border-radius: var(--radius-lg);
  background: var(--surface-2);
}

.panel {
  padding: 1.2rem;
}

.panel-row {
  display: flex;
  justify-content: space-between;
  gap: 1rem;
  align-items: flex-start;
}

.panel-kicker,
.section-kicker,
.surface-kicker {
  color: var(--accent);
  font-size: 0.7rem;
  margin-bottom: 0.35rem;
}

.hero-score {
  font-size: 2.2rem;
  font-weight: 800;
  color: var(--accent);
}

.progress-track {
  height: 10px;
  border-radius: 999px;
  background: rgba(255, 255, 255, 0.06);
  overflow: hidden;
  margin: 1rem 0;
}

.progress-fill {
  width: 0%;
  height: 100%;
  background: linear-gradient(90deg, var(--accent), var(--accent-2));
  border-radius: 999px;
  transition: width 0.25s ease;
}

.metric-grid {
  display: grid;
  grid-template-columns: repeat(3, minmax(0, 1fr));
  gap: 0.75rem;
}

.metric-card,
.spot-card,
.stat-pill {
  border-radius: var(--radius-md);
  border: 1px solid rgba(255, 255, 255, 0.05);
  background: rgba(255, 255, 255, 0.035);
  padding: 0.85rem 0.95rem;
}

.metric-label,
.spot-label {
  display: block;
  font-size: 0.63rem;
  color: var(--muted);
  margin-bottom: 0.45rem;
}

.metric-value,
.spot-value {
  font-size: 1.08rem;
  font-weight: 700;
}

.spotlight-grid {
  display: grid;
  grid-template-columns: repeat(2, minmax(0, 1fr));
  gap: 0.75rem;
  margin: 1rem 0;
}

.main-nav {
  position: sticky;
  top: 0.8rem;
  z-index: 5;
  display: flex;
  gap: 0.7rem;
  flex-wrap: wrap;
  margin: 1.4rem 0 1.5rem;
  padding: 0.9rem;
  border-radius: var(--radius-lg);
  background: rgba(9, 15, 22, 0.82);
  border: 1px solid var(--border);
  backdrop-filter: blur(18px);
}

.nav-tab {
  border-radius: var(--radius-sm);
  padding: 0.86rem 1rem;
  background: rgba(255, 255, 255, 0.04);
  color: var(--muted);
  cursor: pointer;
}

.nav-tab.active {
  background: var(--accent);
  color: #1d1200;
  border-color: rgba(244, 180, 0, 0.45);
}

.content-shell {
  display: grid;
}

.section {
  display: none;
}

.section.active {
  display: block;
  animation: rise 0.28s ease;
}

@keyframes rise {
  from {
    opacity: 0;
    transform: translateY(12px);
  }

  to {
    opacity: 1;
    transform: translateY(0);
  }
}

.section-head,
.surface-head {
  display: flex;
  justify-content: space-between;
  gap: 1rem;
  align-items: flex-start;
}

.section-head {
  margin-bottom: 1.1rem;
}

.dashboard-grid,
.analytics-grid,
.stack {
  display: grid;
  gap: 1rem;
}

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

.surface-card {
  padding: 1.2rem;
}

.stack {
  gap: 1rem;
}

.surface-note,
.section-note {
  margin-top: 1rem;
}

.next-step-card {
  display: grid;
  gap: 0.8rem;
  padding: 1rem;
  border-radius: var(--radius-md);
  background: rgba(255, 255, 255, 0.035);
  border: 1px solid rgba(255, 255, 255, 0.05);
}

.next-step-title {
  font-size: 1.08rem;
  font-weight: 700;
}

.next-step-copy {
  color: var(--muted);
  line-height: 1.7;
}

.achievement-list {
  display: grid;
  gap: 0.8rem;
}

.achievement-item {
  padding: 0.9rem 1rem;
  border-radius: var(--radius-md);
  background: rgba(255, 255, 255, 0.035);
  border: 1px solid rgba(255, 255, 255, 0.05);
}

.achievement-item.locked {
  opacity: 0.72;
}

.achievement-item strong {
  display: block;
  margin-bottom: 0.35rem;
}

.result-badge,
.topic-chip,
.diagram-chip {
  display: inline-flex;
  align-items: center;
  justify-content: center;
  gap: 0.45rem;
  padding: 0.45rem 0.7rem;
  border-radius: 999px;
  font-size: 0.72rem;
}

.result-badge {
  background: rgba(244, 180, 0, 0.12);
  color: var(--accent);
}

.topic-chip,
.diagram-chip {
  background: rgba(255, 255, 255, 0.04);
  border: 1px solid rgba(255, 255, 255, 0.06);
  color: var(--muted);
}

.topic-filter-btn {
  display: inline-flex;
  align-items: center;
  justify-content: center;
  padding: 0.52rem 0.8rem;
  border-radius: 999px;
  border: 1px solid rgba(255, 255, 255, 0.06);
  background: rgba(255, 255, 255, 0.035);
  color: var(--muted);
  cursor: pointer;
  transition: 0.2s ease;
}

.topic-filter-btn.active,
.topic-filter-btn:hover {
  color: var(--accent);
  border-color: rgba(244, 180, 0, 0.2);
  background: rgba(244, 180, 0, 0.1);
}

.topic-chip.active,
.diagram-chip.active {
  background: rgba(244, 180, 0, 0.14);
  color: var(--accent);
  border-color: rgba(244, 180, 0, 0.22);
}

.search-results,
.review-list,
.history-list,
.stats-grid,
.diagram-hotspots,
.diagram-panel,
.practice-controls {
  display: grid;
  gap: 0.8rem;
}

.search-item,
.review-item,
.history-item,
.practice-card,
.quiz-card,
.theory-card {
  border-radius: var(--radius-lg);
  background: var(--surface-2);
  border: 1px solid var(--border);
  box-shadow: var(--shadow);
}

.search-item,
.review-item,
.history-item {
  padding: 1rem;
}

.search-item strong,
.review-item strong,
.history-item strong,
.theory-card h3 {
  font-size: 1.02rem;
}

.search-meta,
.review-meta,
.history-meta {
  color: var(--muted);
  font-size: 0.88rem;
  line-height: 1.65;
  margin-top: 0.5rem;
}

.theory-card,
.practice-card,
.quiz-card {
  padding: 1.35rem;
}

.theory-card h3 {
  display: flex;
  align-items: center;
  gap: 0.75rem;
  margin-bottom: 0.45rem;
}

.icon-box {
  display: inline-flex;
  justify-content: center;
  align-items: center;
  width: 40px;
  height: 40px;
  border-radius: 14px;
  background: rgba(244, 180, 0, 0.14);
  color: var(--accent);
  border: 1px solid rgba(244, 180, 0, 0.18);
}

.theory-lead,
.practice-copy,
.quiz-copy {
  color: var(--muted);
  line-height: 1.72;
  margin-bottom: 1rem;
}

.theory-card p {
  color: #dce3ee;
  line-height: 1.75;
  margin-bottom: 0.8rem;
}

.data-table {
  width: 100%;
  border-collapse: collapse;
  margin: 1rem 0;
  overflow: hidden;
  border-radius: var(--radius-md);
}

.data-table th,
.data-table td {
  padding: 0.78rem 0.9rem;
  text-align: left;
}

.data-table th {
  background: rgba(244, 180, 0, 0.12);
  color: var(--accent);
  font-size: 0.72rem;
  font-family: "Space Mono", monospace;
  letter-spacing: 0.08em;
  text-transform: uppercase;
}

.data-table td {
  border-top: 1px solid rgba(255, 255, 255, 0.05);
  color: #d2d9e3;
}

.callout,
.callout-danger {
  margin-top: 1rem;
  padding: 0.92rem 1rem;
  border-radius: var(--radius-md);
  line-height: 1.68;
}

.callout {
  background: rgba(244, 180, 0, 0.08);
  border: 1px solid rgba(244, 180, 0, 0.14);
  color: #f3dd93;
}

.callout-danger {
  background: rgba(243, 108, 108, 0.08);
  border: 1px solid rgba(243, 108, 108, 0.16);
  color: #ffc3c3;
}

.diagram-shell {
  margin-top: 1rem;
  padding: 1rem;
  border-radius: var(--radius-md);
  background:
    linear-gradient(180deg, rgba(255, 255, 255, 0.03), transparent),
    rgba(8, 14, 20, 0.9);
}

.diagram-canvas {
  width: 100%;
  height: auto;
}

.diagram-hotspots {
  grid-template-columns: repeat(auto-fit, minmax(140px, auto));
  margin-top: 1rem;
}

.diagram-panel {
  margin-top: 0.9rem;
}

.diagram-explain {
  padding: 0.9rem 1rem;
  border-radius: var(--radius-md);
  background: rgba(255, 255, 255, 0.035);
  color: #d8e0eb;
  line-height: 1.7;
}

.flashcard-stage {
  padding: 1rem;
}

.flashcard {
  position: relative;
  width: 100%;
  min-height: 310px;
  border-radius: var(--radius-lg);
  background: transparent;
  cursor: pointer;
  transform-style: preserve-3d;
  transition: transform 0.55s cubic-bezier(0.4, 0, 0.2, 1);
}

.flashcard.flipped {
  transform: rotateY(180deg);
}

.flashcard-face {
  position: absolute;
  inset: 0;
  display: flex;
  flex-direction: column;
  justify-content: center;
  align-items: center;
  gap: 1rem;
  padding: 1.6rem;
  border-radius: var(--radius-lg);
  backface-visibility: hidden;
  text-align: center;
  background:
    linear-gradient(160deg, rgba(244, 180, 0, 0.08), transparent 32%),
    linear-gradient(180deg, rgba(255, 255, 255, 0.05), transparent),
    var(--surface-3);
}

.flashcard-back {
  transform: rotateY(180deg);
  border-color: rgba(244, 180, 0, 0.18);
}

.card-title {
  font-size: clamp(1.4rem, 2vw, 2rem);
  line-height: 1.45;
}

.card-copy {
  max-width: 700px;
  color: #dce4ee;
  line-height: 1.76;
}

.card-topic {
  color: var(--accent);
  font-size: 0.82rem;
}

.control-row {
  justify-content: space-between;
  align-items: center;
  margin-top: 1rem;
}

.control-center {
  display: flex;
  flex-direction: column;
  gap: 0.7rem;
  align-items: center;
}

.counter {
  color: var(--muted);
  font-size: 0.74rem;
}

.practice-card {
  display: grid;
  gap: 1rem;
}

.practice-head,
.quiz-head,
.exam-head,
.history-head {
  display: flex;
  justify-content: space-between;
  gap: 1rem;
  align-items: flex-start;
}

.practice-input {
  width: min(260px, 100%);
  padding: 0.9rem 1rem;
  border-radius: var(--radius-sm);
  border: 1px solid var(--border);
  background: rgba(255, 255, 255, 0.04);
  color: var(--text);
}

.feedback {
  display: none;
  padding: 0.9rem 1rem;
  border-radius: var(--radius-md);
  line-height: 1.7;
}

.feedback.show {
  display: block;
}

.feedback.correct {
  background: rgba(65, 212, 146, 0.1);
  color: #a8efcb;
}

.feedback.wrong {
  background: rgba(243, 108, 108, 0.1);
  color: #ffc4c4;
}

.quiz-card {
  display: grid;
  gap: 1rem;
}

.quiz-question {
  font-size: 1.04rem;
  font-weight: 600;
  line-height: 1.6;
}

.quiz-options {
  display: grid;
  gap: 0.75rem;
}

.quiz-option {
  width: 100%;
  display: flex;
  align-items: flex-start;
  gap: 0.8rem;
  padding: 0.92rem 1rem;
  border-radius: var(--radius-md);
  background: rgba(255, 255, 255, 0.04);
  color: var(--text);
  cursor: pointer;
  text-align: left;
}

.quiz-option:hover:not(.answered) {
  color: var(--accent);
}

.quiz-option.answered {
  cursor: default;
}

.quiz-option.correct {
  background: rgba(65, 212, 146, 0.1);
  border-color: rgba(65, 212, 146, 0.25);
  color: var(--green);
}

.quiz-option.wrong {
  background: rgba(243, 108, 108, 0.1);
  border-color: rgba(243, 108, 108, 0.24);
  color: var(--red);
}

.quiz-option.reveal {
  background: rgba(65, 212, 146, 0.06);
  border-color: rgba(65, 212, 146, 0.18);
  color: #96e5c0;
}

.quiz-option.selected {
  background: rgba(244, 180, 0, 0.1);
  border-color: rgba(244, 180, 0, 0.24);
  color: var(--accent);
}

.option-letter {
  min-width: 20px;
  font-family: "Space Mono", monospace;
  font-size: 0.78rem;
  font-weight: 700;
}

.summary-card,
.banner-card,
.exam-result-card {
  border-radius: var(--radius-lg);
  border: 1px solid var(--border);
  background: var(--surface-2);
  box-shadow: var(--shadow);
  padding: 1.2rem;
  margin-bottom: 1rem;
}

.summary-score,
.exam-score {
  font-size: 2rem;
  font-weight: 800;
  color: var(--accent);
}

.review-list-inline {
  display: grid;
  gap: 0.75rem;
  margin-top: 1rem;
}

.review-inline-item {
  padding: 0.9rem 1rem;
  border-radius: var(--radius-md);
  background: rgba(255, 255, 255, 0.035);
  line-height: 1.65;
}

.exam-shell {
  min-height: 200px;
}

.exam-form-grid {
  display: grid;
  grid-template-columns: repeat(2, minmax(0, 1fr));
  gap: 1rem;
  margin-top: 1rem;
}

.exam-setting {
  display: grid;
  gap: 0.45rem;
}

.exam-setting select {
  padding: 0.85rem 0.95rem;
  border-radius: var(--radius-sm);
  border: 1px solid var(--border);
  background: rgba(255, 255, 255, 0.04);
  color: var(--text);
}

.exam-timer {
  display: inline-flex;
  align-items: center;
  gap: 0.6rem;
  margin-bottom: 1rem;
  padding: 0.8rem 1rem;
  border-radius: var(--radius-md);
  background: rgba(255, 255, 255, 0.04);
  color: var(--accent);
}

.checklist-item {
  display: flex;
  align-items: flex-start;
  gap: 1rem;
  padding: 1rem 1.1rem;
  border-radius: var(--radius-md);
  background: var(--surface-2);
  cursor: pointer;
}

.checklist-item.checked {
  background: linear-gradient(180deg, rgba(65, 212, 146, 0.08), rgba(255, 255, 255, 0.025));
  border-color: rgba(65, 212, 146, 0.24);
}

.check-box {
  width: 24px;
  height: 24px;
  flex-shrink: 0;
  display: inline-flex;
  justify-content: center;
  align-items: center;
  border-radius: 8px;
  border: 1px solid var(--border);
  background: rgba(255, 255, 255, 0.04);
}

.checklist-item.checked .check-box {
  background: var(--green);
  color: #09120f;
}

.check-text {
  color: #dce4ee;
  line-height: 1.7;
}

.checklist-item.checked .check-text {
  color: var(--muted);
  text-decoration: line-through;
}

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

.stat-pill strong {
  display: block;
  font-size: 1.2rem;
  margin-top: 0.35rem;
}

.mastery-list {
  display: grid;
  gap: 0.9rem;
}

.mastery-item {
  display: grid;
  gap: 0.5rem;
}

.mastery-head {
  display: flex;
  justify-content: space-between;
  gap: 0.8rem;
  color: #dce4ee;
}

.mastery-track {
  width: 100%;
  height: 10px;
  border-radius: 999px;
  overflow: hidden;
  background: rgba(255, 255, 255, 0.06);
}

.mastery-fill {
  height: 100%;
  border-radius: 999px;
  background: linear-gradient(90deg, var(--accent), var(--blue));
}

.empty-state {
  padding: 1rem;
  border-radius: var(--radius-md);
  border: 1px dashed var(--border);
  color: var(--muted);
  line-height: 1.7;
}

@media (max-width: 980px) {
  .hero-main,
  .dashboard-grid {
    grid-template-columns: 1fr;
  }

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

@media (max-width: 720px) {
  .app-shell {
    width: min(100% - 1rem, 1220px);
    padding-top: 0.75rem;
  }

  .hero {
    padding: 1.1rem;
  }

  .hero-head,
  .section-head,
  .surface-head,
  .practice-head,
  .quiz-head,
  .exam-head,
  .history-head {
    flex-direction: column;
    align-items: stretch;
  }

  .search-bar,
  .control-row,
  .resource-actions {
    flex-direction: column;
  }

  .metric-grid,
  .spotlight-grid,
  .exam-form-grid,
  .stats-grid {
    grid-template-columns: 1fr;
  }

  .flashcard {
    min-height: 360px;
  }

  .main-nav {
    position: static;
    top: auto;
    margin: 1rem 0 1.1rem;
    padding: 0.65rem;
    gap: 0.55rem;
    flex-wrap: nowrap;
    overflow-x: auto;
    -webkit-overflow-scrolling: touch;
    scrollbar-width: thin;
  }

  .main-nav::-webkit-scrollbar {
    height: 6px;
  }

  .main-nav::-webkit-scrollbar-thumb {
    background: rgba(255, 255, 255, 0.18);
    border-radius: 999px;
  }

  .nav-tab {
    width: auto;
    flex: 0 0 auto;
    white-space: nowrap;
    padding: 0.72rem 0.9rem;
  }

  .icon-btn,
  .action-btn {
    width: 100%;
  }
}

@media print {
  body {
    background: #ffffff;
    color: #111111;
  }

  body::before,
  .hero-backdrop,
  .main-nav,
  .hero-actions,
  .section-actions,
  .resource-actions,
  #exam,
  #analytics {
    display: none !important;
  }

  .hero,
  .panel,
  .surface-card,
  .theory-card,
  .practice-card,
  .quiz-card,
  .checklist-item {
    box-shadow: none;
    border: 1px solid #d0d0d0;
    background: #ffffff;
    color: #111111;
  }

  .section {
    display: block !important;
    margin-bottom: 1.2rem;
  }

  .subtitle,
  .panel-text,
  .section-copy,
  .surface-copy,
  .surface-note,
  .section-note,
  .check-text,
  .theory-card p,
  .card-copy {
    color: #333333 !important;
  }
}

@media (prefers-reduced-motion: reduce) {
  html {
    scroll-behavior: auto;
  }

  *,
  *::before,
  *::after {
    animation-duration: 0.01ms !important;
    animation-iteration-count: 1 !important;
    transition-duration: 0.01ms !important;
  }
}