/* 
 * 多益單字大師 (TOEIC Vocabulary Master) 核心樣式表
 * 規範：全繁體中文註解
 */

:root {
  --primary: #1e40af;
  --primary-hover: #1d4ed8;
  --primary-light: #eff6ff;
  --secondary: #0d9488;
  --accent: #f59e0b;
  --danger: #ef4444;
  --success: #10b981;
  --bg-main: #f8fafc;
  --card-bg: #ffffff;
  --text-main: #0f172a;
  --text-muted: #64748b;
  --border-color: #e2e8f0;
  --shadow-sm: 0 1px 2px 0 rgb(0 0 0 / 0.05);
  --shadow-md: 0 4px 6px -1px rgb(0 0 0 / 0.1), 0 2px 4px -2px rgb(0 0 0 / 0.1);
  --shadow-lg: 0 10px 15px -3px rgb(0 0 0 / 0.1), 0 4px 6px -4px rgb(0 0 0 / 0.1);
  --shadow-xl: 0 20px 25px -5px rgb(0 0 0 / 0.1), 0 8px 10px -6px rgb(0 0 0 / 0.1);
  --radius: 12px;
  --font-family: -apple-system, BlinkMacSystemFont, "Segoe UI", Roboto, "Helvetica Neue", "PingFang TC", "Microsoft JhengHei", sans-serif;
}

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

body {
  font-family: var(--font-family);
  background-color: var(--bg-main);
  color: var(--text-main);
  line-height: 1.6;
  min-height: 100vh;
  display: flex;
  flex-direction: column;
  padding-left: env(safe-area-inset-left);
  padding-right: env(safe-area-inset-right);
}

/* 頂部導覽列 */
.navbar {
  background-color: #ffffff;
  border-bottom: 1px solid var(--border-color);
  position: sticky;
  top: 0;
  z-index: 50;
  box-shadow: var(--shadow-sm);
  padding-top: env(safe-area-inset-top);
}

.nav-container {
  max-width: 1200px;
  margin: 0 auto;
  padding: 0.75rem 1.5rem;
  display: flex;
  align-items: center;
  justify-content: space-between;
  gap: 1rem;
}

.brand {
  display: flex;
  align-items: center;
  gap: 0.75rem;
  text-decoration: none;
  color: var(--text-main);
}

.brand-logo {
  width: 40px;
  height: 40px;
  background: linear-gradient(135deg, #1e40af, #3b82f6);
  border-radius: 10px;
  display: flex;
  align-items: center;
  justify-content: center;
  color: white;
  font-weight: 800;
  font-size: 1.25rem;
  box-shadow: 0 4px 10px rgba(30, 64, 175, 0.3);
}

.brand-info h1 {
  font-size: 1.15rem;
  font-weight: 700;
  line-height: 1.2;
}

.brand-info p {
  font-size: 0.75rem;
  color: var(--text-muted);
}

.nav-stats {
  display: flex;
  align-items: center;
  gap: 1rem;
}

.stat-badge {
  display: flex;
  align-items: center;
  gap: 0.4rem;
  padding: 0.35rem 0.75rem;
  background-color: var(--primary-light);
  border-radius: 9999px;
  font-size: 0.85rem;
  font-weight: 600;
  color: var(--primary);
}

.streak-badge {
  background-color: #fff7ed;
  color: #c2410c;
}

/* 分頁選單導航 */
.tab-nav {
  display: flex;
  padding: 0 1.5rem;
  max-width: 1200px;
  margin: 0 auto;
  width: 100%;
  overflow-x: auto;
  gap: 0.5rem;
  scrollbar-width: none;
  /* 兩側陰影提示尚有內容可橫向捲動，捲到盡頭時自動消失 */
  background:
    linear-gradient(to right, #fff 40%, rgba(255, 255, 255, 0)) left center,
    linear-gradient(to left, #fff 40%, rgba(255, 255, 255, 0)) right center,
    radial-gradient(farthest-side at 0 50%, rgba(15, 23, 42, 0.14), transparent) left center,
    radial-gradient(farthest-side at 100% 50%, rgba(15, 23, 42, 0.14), transparent) right center;
  background-repeat: no-repeat;
  background-size: 36px 100%, 36px 100%, 12px 100%, 12px 100%;
  background-attachment: local, local, scroll, scroll;
  border-bottom: 1px solid var(--border-color);
}
.tab-nav::-webkit-scrollbar {
  display: none;
}

.tab-btn {
  display: flex;
  align-items: center;
  gap: 0.5rem;
  padding: 0.85rem 1rem;
  border: none;
  background: none;
  font-size: 0.95rem;
  font-weight: 600;
  color: var(--text-muted);
  cursor: pointer;
  border-bottom: 3px solid transparent;
  transition: all 0.2s ease;
  white-space: nowrap;
}

.tab-btn:hover {
  color: var(--primary);
}

.tab-btn.active {
  color: var(--primary);
  border-bottom-color: var(--primary);
}

/* 主體內容容器 */
.main-content {
  max-width: 1200px;
  margin: 1.5rem auto;
  padding: 0 1.5rem;
  padding-bottom: calc(1.5rem + env(safe-area-inset-bottom));
  flex: 1;
  width: 100%;
}

.view-section {
  display: none;
}

.view-section.active {
  display: block;
  animation: fadeIn 0.3s ease-in-out;
}

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

/* 卡片與容器樣式 */
.card {
  background: var(--card-bg);
  border-radius: var(--radius);
  border: 1px solid var(--border-color);
  box-shadow: var(--shadow-sm);
  padding: 1.5rem;
  margin-bottom: 1.5rem;
}

.grid-cols-3 {
  display: grid;
  grid-template-columns: repeat(auto-fit, minmax(280px, 1fr));
  gap: 1.25rem;
}

.grid-cols-2 {
  display: grid;
  grid-template-columns: repeat(auto-fit, minmax(320px, 1fr));
  gap: 1.25rem;
}

/* 按鈕樣式 */
.btn {
  display: inline-flex;
  align-items: center;
  justify-content: center;
  gap: 0.5rem;
  padding: 0.6rem 1.25rem;
  border-radius: 8px;
  font-size: 0.95rem;
  font-weight: 600;
  border: 1px solid transparent;
  cursor: pointer;
  transition: all 0.2s ease;
  text-decoration: none;
}

.btn-primary {
  background-color: var(--primary);
  color: white;
}
.btn-primary:hover {
  background-color: var(--primary-hover);
  box-shadow: 0 4px 12px rgba(30, 64, 175, 0.25);
}

.btn-secondary {
  background-color: #f1f5f9;
  color: var(--text-main);
  border-color: var(--border-color);
}
.btn-secondary:hover {
  background-color: #e2e8f0;
}

.btn-success {
  background-color: var(--success);
  color: white;
}
.btn-success:hover {
  background-color: #059669;
}

.btn-accent {
  background-color: var(--accent);
  color: white;
}

.btn-sm {
  padding: 0.35rem 0.75rem;
  font-size: 0.85rem;
}

.btn-lg {
  padding: 0.85rem 1.75rem;
  font-size: 1.1rem;
}

/* 翻轉字卡樣式 (Flashcard 3D Flip) */
.flashcard-wrapper {
  perspective: 1000px;
  max-width: 680px;
  margin: 1.5rem auto;
  height: 440px;
}

.flashcard-inner {
  position: relative;
  width: 100%;
  height: 100%;
  text-align: center;
  transition: transform 0.6s cubic-bezier(0.4, 0, 0.2, 1);
  transform-style: preserve-3d;
  cursor: pointer;
}

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

.flashcard-front,
.flashcard-back {
  position: absolute;
  width: 100%;
  height: 100%;
  -webkit-backface-visibility: hidden;
  backface-visibility: hidden;
  border-radius: 16px;
  border: 1px solid var(--border-color);
  box-shadow: var(--shadow-lg);
  padding: 2.5rem;
  display: flex;
  flex-direction: column;
  justify-content: space-between;
  background: white;
}

.flashcard-back {
  transform: rotateY(180deg);
  background: #fdfefe;
}

.fc-word {
  font-size: 2.75rem;
  font-weight: 800;
  color: var(--primary);
  letter-spacing: -0.02em;
  margin-bottom: 0.25rem;
}

.fc-phonetic {
  font-size: 1.15rem;
  color: var(--text-muted);
  margin-bottom: 1.25rem;
}

.fc-meaning {
  font-size: 1.6rem;
  font-weight: 700;
  color: #1e293b;
  margin-bottom: 0.75rem;
}

.fc-sentence {
  font-size: 1.1rem;
  color: #334155;
  background: #f8fafc;
  padding: 1rem 1.25rem;
  border-radius: 10px;
  border-left: 4px solid var(--primary);
  text-align: left;
  line-height: 1.5;
  margin: 0.75rem 0;
}

.fc-sentence-zh {
  font-size: 0.95rem;
  color: var(--text-muted);
  text-align: left;
  padding-left: 0.25rem;
}

/* 盲聽遮罩模式 */
.blind-mask {
  filter: blur(8px);
  user-select: none;
  transition: filter 0.3s ease;
}

.blind-mask.revealed {
  filter: none;
}

/* 音訊波形動畫效果 */
.audio-pulse {
  display: inline-flex;
  align-items: center;
  gap: 3px;
  height: 18px;
}
.audio-bar {
  width: 3px;
  background-color: var(--primary);
  border-radius: 2px;
  animation: pulseHeight 0.8s ease-in-out infinite alternate;
}
.audio-bar:nth-child(2) { animation-delay: 0.2s; height: 14px; }
.audio-bar:nth-child(3) { animation-delay: 0.4s; height: 8px; }
@keyframes pulseHeight {
  from { height: 4px; }
  to { height: 18px; }
}

/* 測驗選項區 */
.quiz-options {
  display: grid;
  grid-template-columns: 1fr;
  gap: 0.85rem;
  margin: 1.5rem 0;
}

.quiz-opt-btn {
  display: flex;
  align-items: center;
  padding: 1rem 1.25rem;
  background: white;
  border: 2px solid var(--border-color);
  border-radius: 12px;
  font-size: 1.05rem;
  font-weight: 500;
  cursor: pointer;
  transition: all 0.2s ease;
  text-align: left;
}

.quiz-opt-btn:hover {
  border-color: var(--primary);
  background: var(--primary-light);
}

.quiz-opt-btn.correct {
  border-color: var(--success);
  background: #ecfdf5;
  color: #065f46;
}

.quiz-opt-btn.wrong {
  border-color: var(--danger);
  background: #fef2f2;
  color: #991b1b;
}

/* 聽寫練習輸入框 */
.dictation-input {
  font-size: 1.75rem;
  font-weight: 700;
  text-align: center;
  padding: 0.75rem 1.5rem;
  border: 2px solid var(--border-color);
  border-radius: 12px;
  width: 100%;
  max-width: 480px;
  margin: 1.5rem auto;
  display: block;
  letter-spacing: 0.05em;
}
.dictation-input:focus {
  outline: none;
  border-color: var(--primary);
  box-shadow: 0 0 0 3px rgba(59, 130, 246, 0.2);
}

/* 進度條 */
.progress-bar-container {
  width: 100%;
  height: 8px;
  background-color: #e2e8f0;
  border-radius: 9999px;
  overflow: hidden;
}
.progress-bar-fill {
  height: 100%;
  background: linear-gradient(90deg, #3b82f6, #10b981);
  border-radius: 9999px;
  transition: width 0.4s ease;
}

/* 響應式優化 */
@media (max-width: 700px) {
  .nav-container {
    flex-wrap: wrap;
    padding: 0.5rem 0.75rem;
    gap: 0.5rem;
  }
  .brand-logo {
    width: 32px;
    height: 32px;
    font-size: 1rem;
    border-radius: 8px;
  }
  .brand-info h1 {
    font-size: 0.98rem;
  }
  .brand-info p {
    display: none;
  }

  /* 統計徽章壓成單行，避免文字換行撐高整個 header */
  .nav-stats {
    gap: 0.35rem;
    width: 100%;
    overflow-x: auto;
    scrollbar-width: none;
    padding-bottom: 2px;
  }
  .nav-stats::-webkit-scrollbar {
    display: none;
  }
  .stat-badge {
    font-size: 0.7rem;
    padding: 0.2rem 0.5rem;
    gap: 0.25rem;
    white-space: nowrap;
    flex: 0 0 auto;
  }

  .tab-nav {
    padding: 0 0.5rem;
    gap: 0.15rem;
  }
  .tab-btn {
    padding: 0.65rem 0.6rem;
    font-size: 0.82rem;
    gap: 0.3rem;
  }

  .main-content {
    padding: 0 0.6rem;
    margin: 0.6rem auto;
  }
  .card {
    padding: 0.85rem;
    margin-bottom: 0.6rem;
  }

  /* 觸控目標放大到接近 44px */
  .btn {
    padding: 0.7rem 1rem;
  }
  .btn-sm {
    padding: 0.5rem 0.75rem;
  }
  .btn-lg {
    padding: 0.8rem 1.25rem;
  }
  select.btn {
    padding: 0.55rem 0.5rem;
  }

  .flashcard-wrapper {
    margin: 0.6rem auto;
  }
  /* 快捷鍵提示僅適用於實體鍵盤，手機無鍵盤故隱藏以騰出卡片高度 */
  .fc-shortcuts {
    display: none;
  }
  .fc-word {
    font-size: 1.9rem;
  }
  .fc-meaning {
    font-size: 1.2rem;
  }
  .fc-phonetic {
    font-size: 1rem;
    margin-bottom: 0.75rem;
  }
  .flashcard-front,
  .flashcard-back {
    padding: 1.1rem;
  }
  .fc-sentence {
    font-size: 0.95rem;
    padding: 0.7rem 0.85rem;
    margin: 0.5rem 0;
  }
  .fc-sentence-zh {
    font-size: 0.85rem;
  }

  .quiz-opt-btn {
    padding: 0.8rem 0.9rem;
    font-size: 0.98rem;
  }
  .dictation-input {
    font-size: 1.4rem;
    padding: 0.65rem 1rem;
    margin: 1rem auto;
  }
  .grid-cols-3,
  .grid-cols-2 {
    grid-template-columns: 1fr;
    gap: 0.6rem;
  }
}

/* 平板專用區間：700px 以上但不足以用桌機版面
   （iPad mini 直式 744、iPad Air 直式 820、iPad Pro 直式 1024） */
@media (min-width: 701px) and (max-width: 1024px) {
  .main-content {
    padding: 0 1.25rem;
    margin: 1rem auto;
  }
  .card {
    padding: 1.25rem;
  }

  /* 讓 7 個分頁單排顯示，不必橫向捲動（744px 實測需再收緊約 40px） */
  .tab-nav {
    padding: 0 0.75rem;
    gap: 0.1rem;
  }
  .tab-btn {
    padding: 0.8rem 0.3rem;
    font-size: 0.82rem;
    gap: 0.3rem;
  }

  /* 徽章文字不換行，避免撐高 header */
  .nav-stats {
    gap: 0.5rem;
  }
  .stat-badge {
    font-size: 0.78rem;
    padding: 0.3rem 0.6rem;
    white-space: nowrap;
  }

  /* 平板有足夠空間，字卡與字級可放大 */
  .flashcard-wrapper {
    max-width: 760px;
    height: 520px;
  }
  .fc-word {
    font-size: 2.6rem;
  }
  .fc-meaning {
    font-size: 1.5rem;
  }
  .fc-sentence {
    font-size: 1.05rem;
    padding: 0.85rem 1.1rem;
  }

  .grid-cols-3 {
    grid-template-columns: repeat(auto-fit, minmax(240px, 1fr));
  }
}

/* 窄螢幕：隱藏次要統計並壓縮例句字級，讓字卡盡早進入第一屏 */
@media (max-width: 480px) {
  .flashcard-wrapper {
    height: 470px;
  }
  .nav-stats .stat-badge:nth-child(3),
  .nav-stats .stat-badge:nth-child(4) {
    display: none;
  }
  .fc-word {
    font-size: 1.7rem;
  }
  /* 正面例句僅為預覽，完整中英對照在反面，故限制行數避免固定高度卡片爆版 */
  #fcFrontSentenceEn {
    display: -webkit-box;
    -webkit-line-clamp: 3;
    -webkit-box-orient: vertical;
    overflow: hidden;
  }
  .fc-sentence {
    font-size: 0.88rem;
    padding: 0.6rem 0.75rem;
    margin: 0.4rem 0;
  }
  .fc-sentence-zh {
    font-size: 0.82rem;
  }
  .fc-meaning {
    font-size: 1.1rem;
    margin-bottom: 0.4rem;
  }
  .fc-phonetic {
    font-size: 0.92rem;
    margin-bottom: 0.5rem;
  }

  /* 工具列文字不斷詞，寧可整組換行 */
  .fc-toolbar {
    display: flex;
    align-items: center;
    gap: 0.5rem;
    flex-wrap: wrap;
  }
  .fc-toolbar label,
  .fc-toolbar .btn {
    font-size: 0.8rem;
    white-space: nowrap;
  }
}

/* 超窄螢幕（iPhone SE 等級）：反面完整中英例句需要更多高度 */
@media (max-width: 360px) {
  .flashcard-wrapper {
    height: 500px;
  }
  .fc-meaning {
    font-size: 1rem;
  }
  .fc-sentence {
    font-size: 0.82rem;
    padding: 0.5rem 0.65rem;
  }
  .fc-sentence-zh {
    font-size: 0.78rem;
  }
  .quiz-opt-btn {
    padding: 0.7rem 0.75rem;
    font-size: 0.92rem;
  }
}

/* ===== 失落詞境入口（導覽列最右側，連結至獨立頁面 rift.html） ===== */
/* 錨點需清掉瀏覽器預設的底線與藍色，否則會與 .tab-btn 的視覺不一致 */
a.tab-btn {
  text-decoration: none;
  color: #1d6654;
  background: linear-gradient(135deg, #dcfce7, #e5f4ed);
  margin: 0.35rem 0;
  padding: 0.7rem 1rem;
  border-radius: 9999px;
  border-bottom: 3px solid transparent;
  font-weight: 700;
}

a.tab-btn:hover {
  color: #164e40;
  background: linear-gradient(135deg, #bbf7d0, #cfebdf);
}

/* 首頁的遊戲入口，讓窄螢幕不必滑到最後一個頁籤。 */
.game-entry {
  display: flex;
  align-items: center;
  gap: 1rem;
  padding: 1.15rem 1.4rem;
  margin-bottom: 1.5rem;
  border: 1px solid #3a6b61;
  border-radius: 16px;
  color: #f4fff9;
  text-decoration: none;
  background: radial-gradient(circle at 8% 50%, #2e6c60 0, transparent 28%), linear-gradient(110deg, #102d32, #173e3a);
  box-shadow: 0 10px 28px #0d3b3440;
  transition: transform .2s ease, box-shadow .2s ease;
}
.game-entry:hover,.game-entry:focus-visible { transform: translateY(-2px); box-shadow: 0 14px 34px #0d3b3455; }
.game-entry:focus-visible { outline: 3px solid #65d8ae; outline-offset: 3px; }
.game-entry-mark { display: grid; place-items: center; flex: 0 0 54px; height: 54px; border-radius: 16px; color: #dcffd3; background: #2f695d; font-size: 1.8rem; box-shadow: inset 0 0 18px #b5f4c044; }
.game-entry-copy { display: flex; flex-direction: column; min-width: 0; }
.game-entry-copy small { color: #b7e7c7; font-size: .7rem; font-weight: 700; letter-spacing: .12em; }
.game-entry-copy strong { font-size: 1.15rem; line-height: 1.4; }
.game-entry-copy>span { color: #b8d5cc; font-size: .8rem; }
.game-entry-action { display: inline-flex; align-items: center; gap: .5rem; margin-left: auto; padding: .7rem 1rem; border-radius: 10px; background: #a9ebbe; color: #12372d; font-size: .9rem; font-weight: 800; white-space: nowrap; }
@media (max-width: 700px) {
  .game-entry { flex-wrap: wrap; gap: .65rem; padding: 1rem; }
  .game-entry-mark { flex-basis: 42px; height: 42px; font-size: 1.45rem; }
  .game-entry-copy { flex: 1 1 calc(100% - 60px); }
  .game-entry-copy strong { font-size: 1rem; }
  .game-entry-copy>span { font-size: .72rem; }
  .game-entry-action { justify-content: center; margin-left: 0; width: 100%; }
}
@media (prefers-reduced-motion: reduce) { .game-entry { transition: none; } .game-entry:hover { transform: none; } }