:root {
  --primary: #1e40af;
  --primary-dark: #1e3a8a;
  --primary-light: #3b82f6;
  --primary-bg: #eff6ff;
  --accent: #f59e0b;
  --accent-bg: #fffbeb;
  --success: #16a34a;
  --success-bg: #f0fdf4;
  --success-border: #86efac;
  --danger: #dc2626;
  --danger-bg: #fef2f2;
  --danger-border: #fca5a5;
  --purple: #7c3aed;
  --purple-bg: #f5f3ff;
  --text-main: #0f172a;
  --text-muted: #475569;
  --text-soft: #64748b;
  --border: #e2e8f0;
  --card-bg: #ffffff;
  --page-bg: #f1f5f9;
  --radius: 14px;
  --radius-sm: 9px;
  --shadow: 0 4px 18px rgba(15, 23, 42, 0.06);
  --shadow-lg: 0 12px 30px rgba(15, 23, 42, 0.12);
}

* {
  box-sizing: border-box;
}

body {
  margin: 0;
  padding: 0;
  font-family: -apple-system, BlinkMacSystemFont, "Microsoft YaHei", "PingFang SC", "Segoe UI", Roboto, sans-serif;
  background-color: var(--page-bg);
  color: var(--text-main);
  line-height: 1.6;
  min-height: 100vh;
}

.hidden {
  display: none !important;
}

/* Header & Navigation */
.main-header {
  background: linear-gradient(135deg, #1e3a8a 0%, #2563eb 100%);
  color: #ffffff;
  box-shadow: 0 4px 16px rgba(30, 58, 138, 0.22);
  position: sticky;
  top: 0;
  z-index: 50;
}

.header-inner {
  max-width: 1180px;
  margin: 0 auto;
  padding: 14px 18px 12px;
}

.brand-row {
  display: flex;
  align-items: center;
  justify-content: space-between;
  gap: 14px;
  flex-wrap: wrap;
}

.brand-logo {
  display: flex;
  align-items: center;
  gap: 12px;
}

.brand-badge {
  background: var(--accent);
  color: #1e293b;
  font-weight: 800;
  font-size: 0.92rem;
  padding: 6px 11px;
  border-radius: 10px;
  letter-spacing: 0.4px;
  box-shadow: 0 2px 8px rgba(245, 158, 11, 0.35);
}

.brand-logo h1 {
  margin: 0;
  font-size: 1.32rem;
  line-height: 1.25;
}

.brand-sub {
  margin: 2px 0 0;
  font-size: 0.82rem;
  opacity: 0.88;
}

.header-stats {
  display: flex;
  align-items: center;
  gap: 8px;
  flex-wrap: wrap;
}

.stat-pill {
  background: rgba(255, 255, 255, 0.16);
  border: 1px solid rgba(255, 255, 255, 0.28);
  padding: 5px 12px;
  border-radius: 999px;
  font-size: 0.86rem;
  font-weight: 600;
  display: inline-flex;
  align-items: center;
  gap: 4px;
}

.nav-tabs {
  display: flex;
  gap: 8px;
  margin-top: 12px;
  overflow-x: auto;
  padding-bottom: 2px;
}

.nav-btn {
  background: rgba(255, 255, 255, 0.14);
  color: #ffffff;
  border: 1px solid rgba(255, 255, 255, 0.28);
  padding: 7px 14px;
  border-radius: 999px;
  font-size: 0.88rem;
  font-weight: 600;
  cursor: pointer;
  white-space: nowrap;
  transition: all 0.18s ease;
  display: inline-flex;
  align-items: center;
  gap: 6px;
}

.nav-btn:hover {
  background: rgba(255, 255, 255, 0.25);
}

.nav-btn.active {
  background: #ffffff;
  color: var(--primary-dark);
  border-color: #ffffff;
  box-shadow: 0 3px 10px rgba(0, 0, 0, 0.15);
}

.badge-count {
  background: var(--danger);
  color: #ffffff;
  font-size: 0.72rem;
  padding: 1px 6px;
  border-radius: 999px;
  min-width: 18px;
  text-align: center;
}

.nav-btn.active .badge-count {
  background: var(--primary);
}

/* Exam Mode Header */
.exam-header {
  background: #0f172a;
  color: #ffffff;
  position: sticky;
  top: 0;
  z-index: 60;
  border-bottom: 3px solid var(--accent);
}

.exam-header-inner {
  max-width: 1120px;
  margin: 0 auto;
  padding: 12px 18px;
  display: flex;
  align-items: center;
  justify-content: space-between;
  gap: 12px;
  flex-wrap: wrap;
}

.exam-meta {
  display: flex;
  align-items: center;
  gap: 10px;
  flex-wrap: wrap;
}

.exam-tag {
  background: var(--accent);
  color: #0f172a;
  font-weight: 800;
  font-size: 0.78rem;
  padding: 3px 8px;
  border-radius: 6px;
}

.exam-paper-name {
  color: #cbd5e1;
  font-size: 0.92rem;
}

.exam-controls {
  display: flex;
  align-items: center;
  gap: 12px;
}

.exam-timer {
  background: rgba(255, 255, 255, 0.1);
  border: 1px solid rgba(255, 255, 255, 0.25);
  padding: 6px 14px;
  border-radius: 8px;
  font-weight: 700;
  font-variant-numeric: tabular-nums;
  font-size: 1rem;
}

.exam-timer.urgent {
  background: rgba(220, 38, 38, 0.25);
  border-color: #f87171;
  color: #fecaca;
}

/* Layout & Cards */
.main-content {
  max-width: 1180px;
  margin: 22px auto 60px;
  padding: 0 18px;
}

.grid-2 {
  display: grid;
  grid-template-columns: repeat(2, minmax(0, 1fr));
  gap: 18px;
}

.grid-3 {
  display: grid;
  grid-template-columns: repeat(3, minmax(0, 1fr));
  gap: 16px;
}

.grid-4 {
  display: grid;
  grid-template-columns: repeat(4, minmax(0, 1fr));
  gap: 14px;
}

@media (max-width: 900px) {
  .grid-4 { grid-template-columns: repeat(2, minmax(0, 1fr)); }
  .grid-3 { grid-template-columns: repeat(2, minmax(0, 1fr)); }
}

@media (max-width: 680px) {
  .grid-2, .grid-3, .grid-4 { grid-template-columns: 1fr; }
}

.card {
  background: var(--card-bg);
  border: 1px solid var(--border);
  border-radius: var(--radius);
  padding: 20px;
  box-shadow: var(--shadow);
  margin-bottom: 18px;
}

.card-compact {
  padding: 15px 16px;
  margin-bottom: 14px;
}

.card-header {
  display: flex;
  align-items: center;
  justify-content: space-between;
  gap: 12px;
  margin-bottom: 14px;
  flex-wrap: wrap;
}

.card-title {
  margin: 0;
  font-size: 1.12rem;
  font-weight: 700;
  color: var(--text-main);
  display: flex;
  align-items: center;
  gap: 8px;
}

.section-subtitle {
  color: var(--text-muted);
  font-size: 0.9rem;
  margin: 4px 0 0;
}

/* KPI & Progress */
.kpi-card {
  background: var(--card-bg);
  border: 1px solid var(--border);
  border-radius: var(--radius);
  padding: 16px;
  box-shadow: var(--shadow);
}

.kpi-label {
  font-size: 0.82rem;
  color: var(--text-muted);
  font-weight: 600;
}

.kpi-value {
  font-size: 1.65rem;
  font-weight: 800;
  color: var(--primary-dark);
  margin: 4px 0 2px;
}

.kpi-sub {
  font-size: 0.8rem;
  color: var(--text-soft);
}

.progress-track {
  width: 100%;
  height: 10px;
  background: #e2e8f0;
  border-radius: 999px;
  overflow: hidden;
}

.progress-fill {
  height: 100%;
  background: linear-gradient(90deg, var(--primary-light), var(--primary));
  border-radius: 999px;
  transition: width 0.3s ease;
}

.progress-fill.success {
  background: linear-gradient(90deg, #22c55e, #16a34a);
}

/* Buttons */
.btn {
  display: inline-flex;
  align-items: center;
  justify-content: center;
  gap: 6px;
  border: 1px solid transparent;
  border-radius: var(--radius-sm);
  padding: 9px 16px;
  font-size: 0.92rem;
  font-weight: 600;
  cursor: pointer;
  transition: all 0.16s ease;
  font-family: inherit;
}

.btn:disabled {
  opacity: 0.5;
  cursor: not-allowed;
}

.btn-sm {
  padding: 6px 11px;
  font-size: 0.82rem;
}

.btn-primary {
  background: var(--primary);
  color: #ffffff;
}

.btn-primary:hover:not(:disabled) {
  background: var(--primary-dark);
}

.btn-success {
  background: var(--success);
  color: #ffffff;
}

.btn-success:hover:not(:disabled) {
  background: #15803d;
}

.btn-accent {
  background: var(--accent);
  color: #0f172a;
}

.btn-accent:hover:not(:disabled) {
  background: #d97706;
  color: #ffffff;
}

.btn-outline {
  background: #ffffff;
  color: var(--text-main);
  border-color: #cbd5e1;
}

.btn-outline:hover:not(:disabled) {
  background: #f8fafc;
  border-color: var(--primary-light);
  color: var(--primary);
}

.btn-outline-light {
  background: rgba(255, 255, 255, 0.1);
  color: #ffffff;
  border-color: rgba(255, 255, 255, 0.35);
}

.btn-danger-outline {
  background: #ffffff;
  color: var(--danger);
  border-color: #fca5a5;
}

.btn-danger-outline:hover:not(:disabled) {
  background: var(--danger-bg);
}

/* Tags & Pills */
.tag {
  display: inline-flex;
  align-items: center;
  gap: 4px;
  padding: 3px 9px;
  border-radius: 999px;
  font-size: 0.76rem;
  font-weight: 700;
}

.tag-blue { background: var(--primary-bg); color: var(--primary); }
.tag-green { background: var(--success-bg); color: var(--success); }
.tag-amber { background: var(--accent-bg); color: #b45309; }
.tag-purple { background: var(--purple-bg); color: var(--purple); }
.tag-red { background: var(--danger-bg); color: var(--danger); }
.tag-slate { background: #f1f5f9; color: var(--text-muted); }

.pill-bar {
  display: flex;
  gap: 8px;
  flex-wrap: wrap;
  margin-bottom: 14px;
}

.pill-btn {
  border: 1px solid #cbd5e1;
  background: #ffffff;
  color: var(--text-muted);
  padding: 6px 13px;
  border-radius: 999px;
  font-size: 0.85rem;
  font-weight: 600;
  cursor: pointer;
}

.pill-btn.active {
  background: var(--primary);
  color: #ffffff;
  border-color: var(--primary);
}

/* Forms & Inputs */
.form-grid {
  display: grid;
  grid-template-columns: repeat(auto-fit, minmax(190px, 1fr));
  gap: 14px;
}

.form-group label {
  display: block;
  font-size: 0.84rem;
  font-weight: 600;
  color: var(--text-muted);
  margin-bottom: 5px;
}

.input, select, textarea {
  width: 100%;
  border: 1.5px solid #cbd5e1;
  border-radius: var(--radius-sm);
  padding: 8px 11px;
  font-size: 0.94rem;
  font-family: inherit;
  color: var(--text-main);
  background: #ffffff;
}

.input:focus, select:focus, textarea:focus {
  outline: none;
  border-color: var(--primary-light);
  box-shadow: 0 0 0 3px rgba(59, 130, 246, 0.14);
}

/* Task Checklist */
.task-item {
  display: flex;
  align-items: center;
  justify-content: space-between;
  gap: 12px;
  padding: 12px 14px;
  border: 1px solid var(--border);
  border-radius: 10px;
  margin-bottom: 10px;
  background: #ffffff;
  transition: border-color 0.15s ease, background 0.15s ease;
}

.task-item.done {
  background: var(--success-bg);
  border-color: var(--success-border);
}

.task-left {
  display: flex;
  align-items: flex-start;
  gap: 11px;
}

.task-check {
  width: 20px;
  height: 20px;
  margin-top: 3px;
  accent-color: var(--success);
  cursor: pointer;
}

.task-title {
  font-weight: 700;
  font-size: 0.96rem;
}

.task-item.done .task-title {
  text-decoration: line-through;
  color: var(--text-muted);
}

.task-desc {
  font-size: 0.84rem;
  color: var(--text-muted);
}

/* Roadmap Phases */
.phase-card {
  border: 1.5px solid var(--border);
  border-radius: 12px;
  padding: 15px;
  background: #f8fafc;
}

.phase-card.active {
  border-color: var(--primary-light);
  background: var(--primary-bg);
}

/* Flashcards & Vocab */
.flashcard-stage {
  max-width: 560px;
  margin: 12px auto;
}

.flashcard {
  background: linear-gradient(180deg, #ffffff 0%, #f8fafc 100%);
  border: 2px solid #cbd5e1;
  border-radius: 18px;
  padding: 28px 24px;
  text-align: center;
  box-shadow: var(--shadow-lg);
  min-height: 260px;
  display: flex;
  flex-direction: column;
  justify-content: center;
  cursor: pointer;
}

.fc-word {
  font-size: 2.1rem;
  font-weight: 800;
  color: var(--primary-dark);
  margin: 6px 0;
}

.fc-ipa {
  color: var(--text-soft);
  font-size: 0.98rem;
  margin-bottom: 10px;
}

.fc-meaning {
  font-size: 1.25rem;
  font-weight: 700;
  color: var(--text-main);
  margin: 12px 0 8px;
}

.fc-example {
  background: var(--primary-bg);
  border-radius: 10px;
  padding: 10px 14px;
  font-size: 0.92rem;
  color: var(--text-main);
  text-align: left;
  margin-top: 10px;
}

.vocab-table {
  width: 100%;
  border-collapse: collapse;
  font-size: 0.9rem;
}

.vocab-table th, .vocab-table td {
  border-bottom: 1px solid var(--border);
  padding: 9px 10px;
  text-align: left;
  vertical-align: top;
}

.vocab-table th {
  background: #f8fafc;
  color: var(--text-muted);
  font-weight: 700;
  font-size: 0.82rem;
}

/* Grammar Cards */
.grammar-rule-box {
  background: #f8fafc;
  border-left: 4px solid var(--primary);
  padding: 12px 14px;
  border-radius: 0 10px 10px 0;
  margin-bottom: 12px;
}

.trap-box {
  background: var(--accent-bg);
  border-left: 4px solid var(--accent);
  padding: 11px 14px;
  border-radius: 0 10px 10px 0;
  margin-bottom: 12px;
  font-size: 0.9rem;
}

/* Questions & Options */
.q-block {
  border: 1px solid var(--border);
  border-radius: 12px;
  padding: 16px;
  margin-bottom: 14px;
  background: #ffffff;
}

.q-block.correct {
  border-color: var(--success-border);
  background: var(--success-bg);
}

.q-block.wrong {
  border-color: var(--danger-border);
  background: var(--danger-bg);
}

.q-stem {
  font-weight: 600;
  margin-bottom: 10px;
}

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

.opt-label {
  display: flex;
  align-items: flex-start;
  gap: 9px;
  padding: 9px 12px;
  border: 1.5px solid #e2e8f0;
  border-radius: 9px;
  background: #ffffff;
  cursor: pointer;
  transition: all 0.14s ease;
}

.opt-label:hover {
  border-color: var(--primary-light);
  background: #f8fafc;
}

.opt-label.selected {
  border-color: var(--primary);
  background: var(--primary-bg);
}

.opt-label.opt-correct {
  border-color: var(--success);
  background: var(--success-bg);
}

.opt-label.opt-wrong {
  border-color: var(--danger);
  background: var(--danger-bg);
}

.explain-box {
  margin-top: 10px;
  padding: 10px 12px;
  border-radius: 8px;
  background: #ffffff;
  border: 1px solid #cbd5e1;
  font-size: 0.88rem;
  color: var(--text-main);
}

/* Passage & Sign Boxes */
.sign-card {
  border: 2px solid #334155;
  border-radius: 10px;
  background: #fffdf7;
  padding: 12px 14px;
  font-family: "Segoe UI", Tahoma, sans-serif;
  margin-bottom: 10px;
  box-shadow: 0 2px 6px rgba(15, 23, 42, 0.08);
}

.sign-badge {
  font-size: 0.72rem;
  text-transform: uppercase;
  letter-spacing: 0.8px;
  color: var(--text-soft);
  font-weight: 700;
  margin-bottom: 4px;
}

.passage-box {
  background: #f8fafc;
  border: 1px solid #cbd5e1;
  border-radius: 12px;
  padding: 16px 18px;
  margin-bottom: 16px;
  font-size: 0.96rem;
  line-height: 1.75;
}

.inline-gap-input {
  display: inline-block;
  width: 118px;
  border: none;
  border-bottom: 2px solid var(--primary);
  background: #ffffff;
  padding: 2px 6px;
  font-weight: 700;
  color: var(--primary-dark);
  text-align: center;
  margin: 0 3px;
}

/* SVG Picture Cards */
.svg-choice-grid {
  display: grid;
  grid-template-columns: repeat(3, minmax(0, 1fr));
  gap: 10px;
}

@media (max-width: 640px) {
  .svg-choice-grid { grid-template-columns: 1fr; }
}

.svg-choice-card {
  border: 2px solid #cbd5e1;
  border-radius: 11px;
  padding: 8px;
  background: #ffffff;
  cursor: pointer;
  text-align: center;
  transition: all 0.15s ease;
}

.svg-choice-card:hover {
  border-color: var(--primary-light);
}

.svg-choice-card.selected {
  border-color: var(--primary);
  background: var(--primary-bg);
}

.svg-choice-card.opt-correct {
  border-color: var(--success);
  background: var(--success-bg);
}

.svg-choice-card.opt-wrong {
  border-color: var(--danger);
  background: var(--danger-bg);
}

.svg-frame {
  width: 100%;
  aspect-ratio: 4 / 3;
  display: flex;
  align-items: center;
  justify-content: center;
  overflow: hidden;
  border-radius: 8px;
  background: #f8fafc;
}

.story-panels {
  display: grid;
  grid-template-columns: repeat(3, minmax(0, 1fr));
  gap: 12px;
  margin-bottom: 14px;
}

@media (max-width: 720px) {
  .story-panels { grid-template-columns: 1fr; }
}

.story-panel {
  border: 2px solid #334155;
  border-radius: 10px;
  background: #ffffff;
  padding: 8px;
  text-align: center;
}

.speaking-cards-grid {
  display: grid;
  grid-template-columns: repeat(auto-fit, minmax(150px, 1fr));
  gap: 10px;
  margin: 12px 0;
}

/* Audio Player Bar */
.audio-bar {
  display: flex;
  align-items: center;
  justify-content: space-between;
  gap: 12px;
  flex-wrap: wrap;
  background: #0f172a;
  color: #ffffff;
  padding: 12px 16px;
  border-radius: 12px;
  margin-bottom: 16px;
}

.audio-bar audio {
  height: 36px;
  max-width: 100%;
}

/* Writing & Speaking */
.writing-split {
  display: grid;
  grid-template-columns: 1.25fr 0.95fr;
  gap: 16px;
}

@media (max-width: 820px) {
  .writing-split { grid-template-columns: 1fr; }
}

.word-counter {
  font-size: 0.85rem;
  font-weight: 700;
}

.checklist-box {
  background: #f8fafc;
  border: 1px solid var(--border);
  border-radius: 10px;
  padding: 12px 14px;
  font-size: 0.88rem;
}

/* Badges */
.badge-grid {
  display: grid;
  grid-template-columns: repeat(auto-fill, minmax(145px, 1fr));
  gap: 10px;
}

.badge-card {
  border: 1.5px solid var(--border);
  border-radius: 12px;
  padding: 12px 10px;
  text-align: center;
  background: #f8fafc;
  opacity: 0.52;
}

.badge-card.unlocked {
  opacity: 1;
  background: var(--accent-bg);
  border-color: #fcd34d;
}

.badge-icon {
  font-size: 1.8rem;
}

/* Toast & Modal */
.toast {
  position: fixed;
  bottom: 24px;
  right: 24px;
  background: #0f172a;
  color: #ffffff;
  padding: 11px 18px;
  border-radius: 10px;
  font-size: 0.9rem;
  font-weight: 600;
  box-shadow: var(--shadow-lg);
  z-index: 120;
}

.modal-overlay {
  position: fixed;
  inset: 0;
  background: rgba(15, 23, 42, 0.55);
  display: flex;
  align-items: center;
  justify-content: center;
  padding: 16px;
  z-index: 100;
}

.modal-card {
  background: #ffffff;
  border-radius: 16px;
  max-width: 680px;
  width: 100%;
  max-height: 88vh;
  display: flex;
  flex-direction: column;
  box-shadow: var(--shadow-lg);
}

.modal-head {
  display: flex;
  align-items: center;
  justify-content: space-between;
  padding: 14px 18px;
  border-bottom: 1px solid var(--border);
}

.modal-head h3 {
  margin: 0;
  font-size: 1.08rem;
}

.modal-close {
  background: none;
  border: none;
  font-size: 1.5rem;
  cursor: pointer;
  color: var(--text-muted);
}

.modal-body {
  padding: 18px;
  overflow-y: auto;
}

.modal-footer {
  padding: 12px 18px;
  border-top: 1px solid var(--border);
  display: flex;
  justify-content: flex-end;
  gap: 10px;
}

.loading-box {
  text-align: center;
  padding: 60px 20px;
  color: var(--text-muted);
}

/* A4 Print View */
@media print {
  body {
    background: #ffffff;
  }
  .main-header, .exam-header, .no-print, .pill-bar, .btn {
    display: none !important;
  }
  .main-content {
    max-width: 100%;
    margin: 0;
    padding: 0;
  }
  .card, .q-block {
    box-shadow: none;
    break-inside: avoid;
    border-color: #94a3b8;
  }
}