/* ==========================================================================
   Apple Design System & Core Theme - jiangchao.olllll.com
   Design Language: Apple Human Interface Guidelines / Cupertino Web Style
   ========================================================================== */

:root {
  /* Apple Light Mode Palette */
  --apple-bg: #fbfbfd;
  --apple-bg-secondary: #f5f5f7;
  --apple-card-bg: #ffffff;
  --apple-card-border: rgba(0, 0, 0, 0.08);
  --apple-card-shadow: 0 4px 24px rgba(0, 0, 0, 0.04);
  --apple-card-hover-shadow: 0 12px 36px rgba(0, 0, 0, 0.08);
  
  --apple-text-primary: #1d1d1f;
  --apple-text-secondary: #86868b;
  --apple-text-tertiary: #a1a1a6;
  
  --apple-blue: #0071e3;
  --apple-blue-hover: #0077ed;
  --apple-blue-light: rgba(0, 113, 227, 0.08);
  --apple-green: #34c759;
  --apple-green-light: rgba(52, 199, 89, 0.12);
  --apple-red: #ff3b30;
  --apple-red-light: rgba(255, 59, 48, 0.12);
  --apple-orange: #ff9500;
  --apple-orange-light: rgba(255, 149, 0, 0.12);
  --apple-purple: #af52de;
  --apple-purple-light: rgba(175, 82, 222, 0.12);
  
  --apple-nav-bg: rgba(255, 255, 255, 0.82);
  --apple-nav-border: rgba(0, 0, 0, 0.08);
  --apple-blur: saturate(180%) blur(20px);
  
  --apple-radius-sm: 8px;
  --apple-radius-md: 14px;
  --apple-radius-lg: 20px;
  --apple-radius-pill: 9999px;
  
  --apple-transition: all 0.28s cubic-bezier(0.25, 1, 0.5, 1);
  --apple-font: -apple-system, BlinkMacSystemFont, "SF Pro Display", "SF Pro Text", "PingFang SC", "Helvetica Neue", sans-serif;
  --apple-font-mono: "SF Mono", Menlo, Monaco, Consolas, "Courier New", monospace;
}

[data-theme="dark"] {
  /* Apple Dark Mode Palette */
  --apple-bg: #000000;
  --apple-bg-secondary: #161617;
  --apple-card-bg: #1c1c1e;
  --apple-card-border: rgba(255, 255, 255, 0.12);
  --apple-card-shadow: 0 4px 24px rgba(0, 0, 0, 0.3);
  --apple-card-hover-shadow: 0 12px 36px rgba(0, 0, 0, 0.5);
  
  --apple-text-primary: #f5f5f7;
  --apple-text-secondary: #86868b;
  --apple-text-tertiary: #6e6e73;
  
  --apple-blue: #2997ff;
  --apple-blue-hover: #47a7ff;
  --apple-blue-light: rgba(41, 151, 255, 0.15);
  --apple-green: #30d158;
  --apple-green-light: rgba(48, 209, 88, 0.16);
  --apple-red: #ff453a;
  --apple-red-light: rgba(255, 69, 58, 0.16);
  --apple-orange: #ff9f0a;
  --apple-orange-light: rgba(255, 159, 10, 0.16);
  --apple-purple: #bf5af2;
  --apple-purple-light: rgba(191, 90, 242, 0.16);
  
  --apple-nav-bg: rgba(22, 22, 23, 0.82);
  --apple-nav-border: rgba(255, 255, 255, 0.12);
}

* {
  box-sizing: border-box;
  margin: 0;
  padding: 0;
  -webkit-font-smoothing: antialiased;
  -moz-osx-font-smoothing: grayscale;
}

body {
  font-family: var(--apple-font);
  background-color: var(--apple-bg);
  color: var(--apple-text-primary);
  line-height: 1.5;
  transition: background-color 0.3s ease, color 0.3s ease;
  min-height: 100vh;
  display: flex;
  flex-direction: column;
  overflow-x: hidden;
}

/* ==========================================================================
   Header & Navigation (Apple Frosted Glass Navbar)
   ========================================================================== */
.apple-header {
  position: sticky;
  top: 0;
  z-index: 1000;
  background-color: var(--apple-nav-bg);
  backdrop-filter: var(--apple-blur);
  -webkit-backdrop-filter: var(--apple-blur);
  border-bottom: 1px solid var(--apple-nav-border);
  transition: var(--apple-transition);
}

.nav-container {
  max-width: 1200px;
  margin: 0 auto;
  padding: 0 24px;
  height: 52px;
  display: flex;
  align-items: center;
  justify-content: space-between;
}

.brand-wrapper {
  display: flex;
  align-items: center;
  gap: 10px;
  text-decoration: none;
  color: var(--apple-text-primary);
  font-weight: 600;
  font-size: 16px;
  letter-spacing: -0.01em;
}

.brand-icon {
  width: 28px;
  height: 28px;
  background: linear-gradient(135deg, #0071e3 0%, #47a7ff 100%);
  border-radius: 7px;
  display: flex;
  align-items: center;
  justify-content: center;
  color: #ffffff;
  font-size: 14px;
  box-shadow: 0 2px 8px rgba(0, 113, 227, 0.35);
}

.nav-menu {
  display: flex;
  align-items: center;
  list-style: none;
  gap: 8px;
}

.nav-item a, .nav-item button {
  display: flex;
  align-items: center;
  gap: 6px;
  padding: 6px 12px;
  border-radius: var(--apple-radius-pill);
  font-size: 13px;
  font-weight: 400;
  color: var(--apple-text-secondary);
  text-decoration: none;
  background: transparent;
  border: none;
  cursor: pointer;
  transition: var(--apple-transition);
}

.nav-item a:hover, .nav-item button:hover {
  color: var(--apple-text-primary);
  background-color: var(--apple-bg-secondary);
}

.nav-item.active a, .nav-item.active button {
  color: var(--apple-blue);
  background-color: var(--apple-blue-light);
  font-weight: 500;
}

.nav-actions {
  display: flex;
  align-items: center;
  gap: 8px;
}

.icon-btn {
  width: 34px;
  height: 34px;
  border-radius: 50%;
  border: 1px solid var(--apple-card-border);
  background: var(--apple-card-bg);
  color: var(--apple-text-primary);
  display: flex;
  align-items: center;
  justify-content: center;
  cursor: pointer;
  transition: var(--apple-transition);
}

.icon-btn:hover {
  transform: scale(1.04);
  background: var(--apple-bg-secondary);
}

/* ==========================================================================
   Typography & Hero Sections
   ========================================================================== */
.hero-section {
  text-align: center;
  padding: 56px 24px 36px;
  max-width: 900px;
  margin: 0 auto;
}

.hero-badge {
  display: inline-flex;
  align-items: center;
  gap: 6px;
  padding: 4px 14px;
  border-radius: var(--apple-radius-pill);
  background-color: var(--apple-blue-light);
  color: var(--apple-blue);
  font-size: 12px;
  font-weight: 500;
  margin-bottom: 16px;
  letter-spacing: -0.01em;
}

.hero-title {
  font-size: 44px;
  font-weight: 700;
  letter-spacing: -0.03em;
  line-height: 1.15;
  margin-bottom: 14px;
  background: linear-gradient(180deg, var(--apple-text-primary) 0%, var(--apple-text-secondary) 100%);
  -webkit-background-clip: text;
  -webkit-text-fill-color: transparent;
}

.hero-subtitle {
  font-size: 18px;
  color: var(--apple-text-secondary);
  max-width: 650px;
  margin: 0 auto 28px;
  line-height: 1.45;
  font-weight: 400;
}

.hero-buttons {
  display: flex;
  align-items: center;
  justify-content: center;
  gap: 14px;
  flex-wrap: wrap;
}

.btn-primary {
  display: inline-flex;
  align-items: center;
  justify-content: center;
  gap: 8px;
  padding: 10px 22px;
  background-color: var(--apple-blue);
  color: #ffffff;
  border-radius: var(--apple-radius-pill);
  font-size: 14px;
  font-weight: 500;
  text-decoration: none;
  border: none;
  cursor: pointer;
  transition: var(--apple-transition);
  box-shadow: 0 4px 14px rgba(0, 113, 227, 0.28);
}

.btn-primary:hover {
  background-color: var(--apple-blue-hover);
  transform: translateY(-1px);
  box-shadow: 0 6px 20px rgba(0, 113, 227, 0.38);
}

.btn-secondary {
  display: inline-flex;
  align-items: center;
  justify-content: center;
  gap: 8px;
  padding: 10px 22px;
  background-color: var(--apple-bg-secondary);
  color: var(--apple-text-primary);
  border-radius: var(--apple-radius-pill);
  font-size: 14px;
  font-weight: 500;
  text-decoration: none;
  border: 1px solid var(--apple-card-border);
  cursor: pointer;
  transition: var(--apple-transition);
}

.btn-secondary:hover {
  background-color: var(--apple-card-bg);
  transform: translateY(-1px);
  border-color: var(--apple-text-secondary);
}

/* ==========================================================================
   Dashboard Overview & Cards
   ========================================================================== */
.dashboard-grid {
  display: grid;
  grid-template-columns: repeat(auto-fit, minmax(280px, 1fr));
  gap: 20px;
  max-width: 1200px;
  margin: 0 auto 40px;
  padding: 0 24px;
}

.apple-card {
  background: var(--apple-card-bg);
  border: 1px solid var(--apple-card-border);
  border-radius: var(--apple-radius-lg);
  padding: 24px;
  box-shadow: var(--apple-card-shadow);
  transition: var(--apple-transition);
  position: relative;
  overflow: hidden;
}

.apple-card:hover {
  transform: translateY(-3px);
  box-shadow: var(--apple-card-hover-shadow);
  border-color: rgba(0, 113, 227, 0.25);
}

.card-header-icon {
  width: 44px;
  height: 44px;
  border-radius: var(--apple-radius-md);
  display: flex;
  align-items: center;
  justify-content: center;
  font-size: 20px;
  margin-bottom: 16px;
}

.card-title {
  font-size: 18px;
  font-weight: 600;
  margin-bottom: 8px;
  letter-spacing: -0.01em;
}

.card-desc {
  font-size: 13px;
  color: var(--apple-text-secondary);
  line-height: 1.45;
  margin-bottom: 20px;
}

.card-stats-row {
  display: flex;
  align-items: center;
  justify-content: space-between;
  padding-top: 14px;
  border-top: 1px solid var(--apple-card-border);
  font-size: 12px;
  color: var(--apple-text-secondary);
}

.card-progress-bar {
  width: 100%;
  height: 6px;
  background: var(--apple-bg-secondary);
  border-radius: var(--apple-radius-pill);
  overflow: hidden;
  margin: 10px 0 14px;
}

.card-progress-fill {
  height: 100%;
  background: linear-gradient(90deg, var(--apple-blue) 0%, var(--apple-green) 100%);
  border-radius: var(--apple-radius-pill);
  transition: width 0.5s ease;
}

/* ==========================================================================
   Quiz Interface Components
   ========================================================================== */
.quiz-layout {
  max-width: 1000px;
  margin: 0 auto 60px;
  padding: 0 20px;
  display: flex;
  flex-direction: column;
  gap: 20px;
}

.quiz-top-bar {
  display: flex;
  align-items: center;
  justify-content: space-between;
  padding: 12px 18px;
  background: var(--apple-card-bg);
  border: 1px solid var(--apple-card-border);
  border-radius: var(--apple-radius-md);
  font-size: 13px;
}

.mode-selector {
  display: flex;
  background: var(--apple-bg-secondary);
  padding: 3px;
  border-radius: var(--apple-radius-pill);
  gap: 2px;
}

.mode-btn {
  padding: 5px 14px;
  border-radius: var(--apple-radius-pill);
  font-size: 12px;
  font-weight: 500;
  color: var(--apple-text-secondary);
  background: transparent;
  border: none;
  cursor: pointer;
  transition: var(--apple-transition);
}

.mode-btn.active {
  background: var(--apple-card-bg);
  color: var(--apple-text-primary);
  box-shadow: 0 2px 6px rgba(0, 0, 0, 0.08);
}

.question-card {
  background: var(--apple-card-bg);
  border: 1px solid var(--apple-card-border);
  border-radius: var(--apple-radius-lg);
  padding: 32px;
  box-shadow: var(--apple-card-shadow);
  transition: var(--apple-transition);
}

.case-background-box {
  background: var(--apple-bg-secondary);
  border-radius: var(--apple-radius-md);
  padding: 18px 20px;
  margin-bottom: 24px;
  border-left: 4px solid var(--apple-blue);
  font-size: 14px;
  line-height: 1.6;
  color: var(--apple-text-primary);
}

.case-title {
  font-weight: 600;
  color: var(--apple-blue);
  margin-bottom: 6px;
  display: flex;
  align-items: center;
  gap: 6px;
}

.q-meta-header {
  display: flex;
  align-items: center;
  justify-content: space-between;
  margin-bottom: 18px;
}

.q-type-badge {
  padding: 4px 10px;
  border-radius: 6px;
  font-size: 12px;
  font-weight: 600;
  letter-spacing: 0.02em;
}

.badge-single {
  background: var(--apple-blue-light);
  color: var(--apple-blue);
}

.badge-multi {
  background: var(--apple-purple-light);
  color: var(--apple-purple);
}

.badge-case {
  background: var(--apple-orange-light);
  color: var(--apple-orange);
}

.q-content {
  font-size: 18px;
  font-weight: 500;
  line-height: 1.5;
  margin-bottom: 24px;
  color: var(--apple-text-primary);
}

.options-list {
  display: flex;
  flex-direction: column;
  gap: 12px;
  margin-bottom: 28px;
}

.option-item {
  display: flex;
  align-items: flex-start;
  gap: 14px;
  padding: 16px 20px;
  background: var(--apple-bg-secondary);
  border: 1.5px solid transparent;
  border-radius: var(--apple-radius-md);
  cursor: pointer;
  transition: var(--apple-transition);
  font-size: 15px;
  line-height: 1.45;
  color: var(--apple-text-primary);
}

.option-item:hover {
  background: var(--apple-card-bg);
  border-color: var(--apple-text-secondary);
  transform: translateX(2px);
}

.option-item.selected {
  border-color: var(--apple-blue);
  background: var(--apple-blue-light);
  font-weight: 500;
}

.option-item.correct {
  border-color: var(--apple-green);
  background: var(--apple-green-light);
  font-weight: 500;
}

.option-item.wrong {
  border-color: var(--apple-red);
  background: var(--apple-red-light);
}

.option-key {
  width: 26px;
  height: 26px;
  border-radius: 50%;
  background: var(--apple-card-bg);
  border: 1px solid var(--apple-card-border);
  display: flex;
  align-items: center;
  justify-content: center;
  font-weight: 600;
  font-size: 13px;
  flex-shrink: 0;
  margin-top: 1px;
}

.option-item.selected .option-key {
  background: var(--apple-blue);
  color: #ffffff;
  border-color: var(--apple-blue);
}

.option-item.correct .option-key {
  background: var(--apple-green);
  color: #ffffff;
  border-color: var(--apple-green);
}

.option-item.wrong .option-key {
  background: var(--apple-red);
  color: #ffffff;
  border-color: var(--apple-red);
}

/* ==========================================================================
   Analysis & Explanation Section
   ========================================================================== */
.explanation-box {
  background: var(--apple-bg-secondary);
  border: 1px solid var(--apple-card-border);
  border-radius: var(--apple-radius-md);
  padding: 22px;
  margin-top: 24px;
  animation: fadeIn 0.3s ease-out;
}

.ans-banner {
  display: flex;
  align-items: center;
  gap: 12px;
  margin-bottom: 16px;
  padding-bottom: 14px;
  border-bottom: 1px solid var(--apple-card-border);
}

.ans-tag {
  font-size: 13px;
  font-weight: 600;
  padding: 3px 10px;
  border-radius: var(--apple-radius-pill);
}

.ans-correct-tag {
  background: var(--apple-green-light);
  color: var(--apple-green);
}

.ans-law-citation {
  display: inline-flex;
  align-items: center;
  gap: 6px;
  font-size: 12px;
  font-weight: 500;
  color: var(--apple-blue);
  background: var(--apple-blue-light);
  padding: 4px 10px;
  border-radius: 6px;
  margin-bottom: 12px;
}

.analysis-text {
  font-size: 14px;
  line-height: 1.7;
  color: var(--apple-text-primary);
}

.analysis-section-title {
  font-weight: 600;
  margin-top: 10px;
  margin-bottom: 4px;
  color: var(--apple-text-primary);
}

/* ==========================================================================
   Floating Controls Dock
   ========================================================================== */
.bottom-dock {
  position: sticky;
  bottom: 20px;
  z-index: 900;
  max-width: 680px;
  margin: 0 auto;
  background: var(--apple-nav-bg);
  backdrop-filter: var(--apple-blur);
  -webkit-backdrop-filter: var(--apple-blur);
  border: 1px solid var(--apple-nav-border);
  border-radius: var(--apple-radius-pill);
  padding: 10px 18px;
  display: flex;
  align-items: center;
  justify-content: space-between;
  box-shadow: 0 10px 30px rgba(0, 0, 0, 0.12);
}

.dock-btn {
  display: inline-flex;
  align-items: center;
  gap: 6px;
  padding: 8px 16px;
  border-radius: var(--apple-radius-pill);
  border: none;
  background: transparent;
  color: var(--apple-text-primary);
  font-size: 13px;
  font-weight: 500;
  cursor: pointer;
  transition: var(--apple-transition);
}

.dock-btn:hover {
  background: var(--apple-bg-secondary);
}

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

.dock-btn-primary:hover {
  background: var(--apple-blue-hover);
}

@keyframes fadeIn {
  from { opacity: 0; transform: translateY(6px); }
  to { opacity: 1; transform: translateY(0); }
}

@media (max-width: 768px) {
  .hero-title { font-size: 30px; }
  .q-content { font-size: 16px; }
  .nav-menu { display: none; }
  .nav-container { padding: 0 16px; }
  .dashboard-grid { grid-template-columns: 1fr; }
}