/* ========== CSS Variables ========== */
:root {
  /* ダークモード（デフォルト） */
  --bg-dark: #0a0a0f;
  --bg-card: #12121a;
  --bg-sidebar: #0d0d14;
  --bg-hover: #1a1a25;
  --accent-cyan: #00d4ff;
  --accent-cyan-dim: rgba(0, 212, 255, 0.1);
  --accent-purple: #a855f7;
  --accent-green: #22c55e;
  --text-primary: #f0f0f5;
  --text-secondary: #8888a0;
  --text-dim: #555566;
  --border-color: #222233;
  --freq-bar: linear-gradient(90deg, #00d4ff, #a855f7);
}

/* ライトモード */
[data-theme="light"] {
  --bg-dark: #f5f7fa;
  --bg-card: #ffffff;
  --bg-sidebar: #ffffff;
  --bg-hover: #e8ecf2;
  --accent-cyan: #0095cc;
  --accent-cyan-dim: rgba(0, 149, 204, 0.1);
  --accent-purple: #9333ea;
  --text-primary: #1a1a2e;
  --text-secondary: #5a5a7a;
  --text-dim: #9999aa;
  --border-color: #e0e4ea;
  --freq-bar: linear-gradient(90deg, #0095cc, #9333ea);
}

/* ========== Reset & Base ========== */
* {
  margin: 0;
  padding: 0;
  box-sizing: border-box;
}

html {
  scroll-behavior: smooth;
}

body {
  font-family: 'Inter', 'Noto Sans JP', sans-serif;
  background: var(--bg-dark);
  color: var(--text-primary);
  line-height: 1.6;
  min-height: 100vh;
}

/* ========== Layout ========== */
.container {
  display: flex;
  min-height: 100vh;
}

/* ========== Sidebar ========== */
.sidebar {
  width: 280px;
  background: var(--bg-sidebar);
  border-right: 1px solid var(--border-color);
  position: fixed;
  top: 0;
  left: 0;
  height: 100vh;
  overflow-y: auto;
  z-index: 100;
  transition: transform 0.3s ease;
}

.sidebar-header {
  padding: 24px 20px;
  border-bottom: 1px solid var(--border-color);
  position: sticky;
  top: 0;
  background: var(--bg-sidebar);
  z-index: 10;
}

.logo {
  display: flex;
  align-items: center;
  gap: 10px;
  margin-bottom: 8px;
}

.logo-icon {
  width: 36px;
  height: 36px;
  background: var(--freq-bar);
  border-radius: 8px;
  display: flex;
  align-items: center;
  justify-content: center;
  font-weight: 700;
  font-size: 14px;
  color: var(--bg-dark);
}

[data-theme="light"] .logo-icon {
  color: #ffffff;
}

.logo-text {
  font-size: 20px;
  font-weight: 700;
  color: var(--text-primary);
  letter-spacing: -0.5px;
}

.logo-text span {
  color: var(--accent-cyan);
}

.tagline {
  font-size: 11px;
  color: var(--text-secondary);
  line-height: 1.5;
}

/* Stats Box */
.stats-box {
  margin: 16px 12px;
  padding: 16px;
  background: var(--bg-card);
  border-radius: 12px;
  border: 1px solid var(--border-color);
}

.stats-row {
  display: flex;
  justify-content: space-between;
  align-items: center;
  padding: 6px 0;
}

.stats-label {
  font-size: 11px;
  color: var(--text-secondary);
}

.stats-value {
  font-size: 13px;
  font-weight: 600;
  color: var(--accent-cyan);
}

.coverage-bar {
  margin-top: 12px;
}

.coverage-bar-label {
  display: flex;
  justify-content: space-between;
  font-size: 10px;
  margin-bottom: 6px;
}

.coverage-bar-track {
  height: 6px;
  background: var(--bg-dark);
  border-radius: 3px;
  overflow: hidden;
}

.coverage-bar-fill {
  height: 100%;
  background: var(--freq-bar);
  border-radius: 3px;
  transition: width 0.5s ease;
}

/* Theme Toggle */
.theme-toggle-wrapper {
  padding: 0 12px;
  margin-bottom: 16px;
}

.theme-toggle {
  display: flex;
  align-items: center;
  gap: 8px;
  background: var(--bg-card);
  border: 1px solid var(--border-color);
  border-radius: 24px;
  padding: 6px 12px;
  cursor: pointer;
  transition: all 0.3s ease;
  user-select: none;
}

.theme-toggle:hover {
  border-color: var(--accent-cyan);
}

.theme-toggle-track {
  width: 44px;
  height: 24px;
  background: var(--bg-dark);
  border-radius: 12px;
  position: relative;
  transition: background 0.3s ease;
}

.theme-toggle-thumb {
  width: 20px;
  height: 20px;
  background: var(--accent-cyan);
  border-radius: 50%;
  position: absolute;
  top: 2px;
  left: 2px;
  transition: transform 0.3s ease;
  display: flex;
  align-items: center;
  justify-content: center;
  font-size: 12px;
}

[data-theme="light"] .theme-toggle-thumb {
  transform: translateX(20px);
}

.theme-toggle-label {
  font-size: 12px;
  color: var(--text-secondary);
  font-weight: 500;
}

/* Navigation */
.nav-section {
  padding: 16px 12px;
}

.nav-title {
  font-size: 10px;
  font-weight: 600;
  color: var(--text-dim);
  text-transform: uppercase;
  letter-spacing: 1px;
  padding: 0 8px;
  margin-bottom: 8px;
}

.nav-group {
  margin-bottom: 4px;
}

.nav-group-header {
  display: flex;
  align-items: center;
  justify-content: space-between;
  padding: 10px 12px;
  border-radius: 8px;
  cursor: pointer;
  transition: all 0.2s;
  user-select: none;
}

.nav-group-header:hover {
  background: var(--bg-hover);
}

.nav-group-header.active {
  background: var(--accent-cyan-dim);
}

.nav-group-label {
  display: flex;
  align-items: center;
  gap: 10px;
  font-size: 13px;
  font-weight: 500;
}

.nav-group-icon {
  font-size: 14px;
}

.nav-group-arrow {
  font-size: 10px;
  color: var(--text-dim);
  transition: transform 0.2s;
}

.nav-group.open .nav-group-arrow {
  transform: rotate(180deg);
}

.nav-items {
  display: none;
  padding: 4px 0 4px 20px;
}

.nav-group.open .nav-items {
  display: block;
}

.nav-item {
  display: block;
  padding: 8px 12px;
  font-size: 12px;
  color: var(--text-secondary);
  text-decoration: none;
  border-radius: 6px;
  transition: all 0.2s;
  cursor: pointer;
}

.nav-item:hover {
  background: var(--bg-hover);
  color: var(--text-primary);
}

.nav-item.active {
  background: var(--accent-cyan-dim);
  color: var(--accent-cyan);
}

.nav-item.loaded::after {
  content: "✓";
  margin-left: 6px;
  color: var(--accent-green);
  font-size: 10px;
}

/* ========== Main Content ========== */
.main {
  flex: 1;
  margin-left: 280px;
  padding: 0;
}

/* Header */
.header {
  position: sticky;
  top: 0;
  background: rgba(10, 10, 15, 0.9);
  backdrop-filter: blur(12px);
  border-bottom: 1px solid var(--border-color);
  padding: 16px 32px;
  z-index: 50;
  display: flex;
  align-items: center;
  justify-content: space-between;
}

[data-theme="light"] .header {
  background: rgba(245, 247, 250, 0.9);
}

.header-title {
  font-size: 14px;
  color: var(--text-secondary);
}

.header-title strong {
  color: var(--text-primary);
  font-weight: 600;
}

.search-box {
  display: flex;
  align-items: center;
  gap: 8px;
  background: var(--bg-card);
  border: 1px solid var(--border-color);
  border-radius: 8px;
  padding: 8px 14px;
  width: 280px;
  transition: border-color 0.2s;
}

.search-box:focus-within {
  border-color: var(--accent-cyan);
}

.search-box input {
  flex: 1;
  background: none;
  border: none;
  outline: none;
  color: var(--text-primary);
  font-size: 13px;
  font-family: inherit;
}

.search-box input::placeholder {
  color: var(--text-dim);
}

.search-icon {
  color: var(--text-dim);
  font-size: 14px;
}

/* Word List */
.word-list {
  padding: 24px 32px;
  max-width: 900px;
}

.word-card {
  background: var(--bg-card);
  border: 1px solid var(--border-color);
  border-radius: 16px;
  margin-bottom: 16px;
  overflow: hidden;
  transition: all 0.3s ease;
  animation: fadeInUp 0.4s ease forwards;
  opacity: 0;
}

.word-card:hover {
  border-color: var(--accent-cyan);
  transform: translateY(-2px);
  box-shadow: 0 8px 32px rgba(0, 212, 255, 0.1);
}

[data-theme="light"] .word-card {
  box-shadow: 0 2px 8px rgba(0, 0, 0, 0.06);
}

[data-theme="light"] .word-card:hover {
  box-shadow: 0 8px 32px rgba(0, 149, 204, 0.15);
}

.word-card-header {
  display: flex;
  align-items: center;
  justify-content: space-between;
  padding: 20px 24px;
  border-bottom: 1px solid var(--border-color);
}

.word-rank {
  display: flex;
  align-items: center;
  gap: 16px;
}

.rank-number {
  width: 48px;
  height: 48px;
  background: var(--accent-cyan-dim);
  border-radius: 12px;
  display: flex;
  align-items: center;
  justify-content: center;
  font-family: 'JetBrains Mono', monospace;
  font-size: 16px;
  font-weight: 600;
  color: var(--accent-cyan);
}

.word-main {
  display: flex;
  flex-direction: column;
  gap: 4px;
}

.word-en {
  font-size: 28px;
  font-weight: 700;
  color: var(--text-primary);
  letter-spacing: -0.5px;
}

.word-jp {
  font-size: 16px;
  color: var(--accent-cyan);
  font-weight: 500;
}

.word-freq {
  text-align: right;
}

.freq-label {
  font-size: 10px;
  color: var(--text-dim);
  text-transform: uppercase;
  letter-spacing: 0.5px;
}

.freq-bar-mini {
  width: 80px;
  height: 4px;
  background: var(--bg-dark);
  border-radius: 2px;
  margin-top: 6px;
  overflow: hidden;
}

.freq-bar-mini-fill {
  height: 100%;
  background: var(--freq-bar);
  border-radius: 2px;
}

/* Phrases */
.word-card-body {
  padding: 20px 24px;
}

.phrases-title {
  font-size: 11px;
  font-weight: 600;
  color: var(--text-dim);
  text-transform: uppercase;
  letter-spacing: 1px;
  margin-bottom: 12px;
  display: flex;
  align-items: center;
  gap: 6px;
}

.phrases-title::before {
  content: "💡";
  font-size: 12px;
}

.phrases-list {
  display: flex;
  flex-direction: column;
  gap: 10px;
}

.phrase-item {
  display: flex;
  align-items: center;
  gap: 12px;
  padding: 12px 16px;
  background: var(--bg-dark);
  border-radius: 10px;
  transition: all 0.2s;
}

.phrase-item:hover {
  background: var(--bg-hover);
}

.phrase-en {
  flex: 1;
  font-size: 14px;
  font-weight: 500;
  color: var(--text-primary);
  font-family: 'JetBrains Mono', monospace;
}

.phrase-arrow {
  color: var(--accent-purple);
  font-size: 12px;
}

.phrase-jp {
  flex: 1;
  font-size: 14px;
  color: var(--text-secondary);
}

/* Load More */
.load-more-container {
  padding: 20px 32px 40px;
  text-align: center;
}

.load-more-btn {
  padding: 14px 32px;
  background: var(--accent-cyan-dim);
  border: 1px solid var(--accent-cyan);
  border-radius: 12px;
  color: var(--accent-cyan);
  font-size: 14px;
  font-weight: 600;
  cursor: pointer;
  transition: all 0.2s;
}

.load-more-btn:hover {
  background: var(--accent-cyan);
  color: var(--bg-dark);
}

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

/* Loading */
.loading {
  text-align: center;
  padding: 60px 20px;
  color: var(--text-secondary);
}

.loading-spinner {
  border: 3px solid var(--border-color);
  border-top: 3px solid var(--accent-cyan);
  border-radius: 50%;
  width: 40px;
  height: 40px;
  animation: spin 1s linear infinite;
  margin: 0 auto 16px;
}

@keyframes spin {
  0% { transform: rotate(0deg); }
  100% { transform: rotate(360deg); }
}

@keyframes fadeInUp {
  from {
    opacity: 0;
    transform: translateY(20px);
  }
  to {
    opacity: 1;
    transform: translateY(0);
  }
}

/* No Results */
.no-results {
  text-align: center;
  padding: 60px 20px;
  color: var(--text-secondary);
}

.no-results-icon {
  font-size: 48px;
  margin-bottom: 16px;
}

.no-results-text {
  font-size: 16px;
}

/* ========== Mobile ========== */
.mobile-menu-btn {
  display: none;
  position: fixed;
  bottom: 24px;
  right: 24px;
  width: 56px;
  height: 56px;
  background: var(--accent-cyan);
  border: none;
  border-radius: 50%;
  color: var(--bg-dark);
  font-size: 24px;
  cursor: pointer;
  z-index: 200;
  box-shadow: 0 4px 20px rgba(0, 212, 255, 0.4);
}

.sidebar-overlay {
  display: none;
  position: fixed;
  top: 0;
  left: 0;
  width: 100%;
  height: 100%;
  background: rgba(0, 0, 0, 0.5);
  z-index: 90;
}

@media (max-width: 768px) {
  .sidebar {
    transform: translateX(-100%);
  }

  .sidebar.open {
    transform: translateX(0);
  }

  .sidebar-overlay.open {
    display: block;
  }

  .main {
    margin-left: 0;
  }

  .mobile-menu-btn {
    display: flex;
    align-items: center;
    justify-content: center;
  }

  .header {
    padding: 12px 16px;
    flex-direction: column;
    gap: 12px;
    align-items: stretch;
  }

  .search-box {
    width: 100%;
  }

  .word-list {
    padding: 16px;
  }

  .word-card-header {
    flex-direction: column;
    align-items: flex-start;
    gap: 12px;
  }

  .word-freq {
    text-align: left;
  }

  .phrase-item {
    flex-direction: column;
    align-items: flex-start;
    gap: 4px;
  }

  .phrase-arrow {
    transform: rotate(90deg);
  }

  .load-more-container {
    padding: 20px 16px 40px;
  }
}

/* ========== Scrollbar ========== */
::-webkit-scrollbar {
  width: 8px;
}

::-webkit-scrollbar-track {
  background: var(--bg-dark);
}

::-webkit-scrollbar-thumb {
  background: var(--border-color);
  border-radius: 4px;
}

::-webkit-scrollbar-thumb:hover {
  background: var(--text-dim);
}