/* ==========================================================================
   考研英语作文背诵通关 (Recite-Essay Master) 精美定制样式表
   ========================================================================== */

:root {
  --font-sans: -apple-system, BlinkMacSystemFont, "Segoe UI", Roboto, "PingFang SC", "Hiragino Sans GB", "Microsoft YaHei", sans-serif;
  --font-serif: "Georgia", "Cambria", "Times New Roman", serif;

  /* 主题色盘 (Light 经典模式) */
  --bg-main: #f8fafc;
  --bg-card: #ffffff;
  --bg-card-sub: #f1f5f9;
  --text-main: #0f172a;
  --text-muted: #64748b;
  --border-color: #e2e8f0;

  --color-primary: #4f46e5;
  --color-primary-hover: #4338ca;
  --color-primary-light: #eef2ff;

  --color-success: #10b981;
  --color-success-light: #ecfdf5;

  --color-warning: #f59e0b;
  --color-warning-light: #fffbeb;

  --color-danger: #ef4444;
  --color-danger-light: #fef2f2;

  --shadow-sm: 0 1px 2px 0 rgb(0 0 0 / 0.05);
  --shadow-md: 0 4px 6px -1px rgb(0 0 0 / 0.08), 0 2px 4px -2px rgb(0 0 0 / 0.06);
  --shadow-lg: 0 10px 15px -3px rgb(0 0 0 / 0.08), 0 4px 6px -4px rgb(0 0 0 / 0.04);
  --shadow-xl: 0 20px 25px -5px rgb(0 0 0 / 0.1), 0 8px 10px -6px rgb(0 0 0 / 0.05);
}

/* 护眼羊皮纸暖白模式 (Eye-Care Warm Mode) */
[data-theme="warm"] {
  --bg-main: #fcf8ee;
  --bg-card: #fffef9;
  --bg-card-sub: #f7f1df;
  --text-main: #2d2a24;
  --text-muted: #78716c;
  --border-color: #e7dfc6;

  --color-primary: #b45309;
  --color-primary-hover: #92400e;
  --color-primary-light: #fef3c7;
}

/* 深空护眼暗黑模式 (Dark Mode) */
[data-theme="dark"] {
  --bg-main: #0b0f19;
  --bg-card: #131b2e;
  --bg-card-sub: #1e293b;
  --text-main: #f1f5f9;
  --text-muted: #94a3b8;
  --border-color: #283548;

  --color-primary: #6366f1;
  --color-primary-hover: #818cf8;
  --color-primary-light: #1e1e38;

  --color-success-light: #064e3b;
  --color-warning-light: #78350f;
  --color-danger-light: #7f1d1d;
}

* {
  box-sizing: border-box;
  margin: 0;
  padding: 0;
  -webkit-tap-highlight-color: transparent;
}

body {
  font-family: var(--font-sans);
  background-color: var(--bg-main);
  color: var(--text-main);
  min-height: 100vh;
  line-height: 1.6;
  transition: background-color 0.3s ease, color 0.3s ease;
  overflow-x: hidden;
}

/* 滚动条美化 */
::-webkit-scrollbar {
  width: 6px;
  height: 6px;
}
::-webkit-scrollbar-track {
  background: transparent;
}
::-webkit-scrollbar-thumb {
  background: var(--border-color);
  border-radius: 9999px;
}
::-webkit-scrollbar-thumb:hover {
  background: var(--text-muted);
}

/* 容器与版心 */
.container {
  max-width: 1200px;
  margin-left: auto;
  margin-right: auto;
  padding: 1rem;
}

/* 顶部导航栏 */
.navbar {
  position: sticky;
  top: 0;
  z-index: 50;
  background: rgba(255, 255, 255, 0.85);
  backdrop-filter: blur(12px);
  -webkit-backdrop-filter: blur(12px);
  border-bottom: 1px solid var(--border-color);
  transition: background 0.3s ease, border-color 0.3s ease;
}
[data-theme="warm"] .navbar {
  background: rgba(252, 248, 238, 0.9);
}
[data-theme="dark"] .navbar {
  background: rgba(19, 27, 46, 0.85);
}

/* 标签栏 */
.tab-btn {
  position: relative;
  transition: all 0.2s ease;
  font-weight: 500;
  white-space: nowrap;
}
.tab-btn.active {
  color: var(--color-primary);
  font-weight: 600;
}
.tab-btn.active::after {
  content: '';
  position: absolute;
  bottom: -1px;
  left: 0;
  right: 0;
  height: 2px;
  background-color: var(--color-primary);
  border-radius: 9999px;
}

/* 3D 闪卡翻转特效容器 */
.card-perspective {
  perspective: 1200px;
}
.card-flipper {
  position: relative;
  width: 100%;
  min-height: 280px;
  transition: transform 0.5s cubic-bezier(0.4, 0, 0.2, 1);
  transform-style: preserve-3d;
  cursor: pointer;
}
.card-flipper.flipped {
  transform: rotateY(180deg);
}
.card-face {
  position: absolute;
  top: 0;
  left: 0;
  width: 100%;
  height: 100%;
  border-radius: 1rem;
  background-color: var(--bg-card);
  border: 1px solid var(--border-color);
  box-shadow: var(--shadow-md);
  padding: 1.5rem;
  display: flex;
  flex-direction: column;
  justify-content: space-between;
  backface-visibility: hidden;
  -webkit-backface-visibility: hidden;
  overflow-y: auto;
}
.card-face-back {
  transform: rotateY(180deg);
  background-color: var(--bg-card);
}

/* 挖空与遮罩默写 (Cloze Mask) */
.cloze-mask {
  display: inline-block;
  background-color: rgba(99, 102, 241, 0.12);
  filter: blur(6px);
  border-radius: 4px;
  padding: 0 4px;
  margin: 0 2px;
  cursor: pointer;
  user-select: none;
  transition: filter 0.25s ease, background-color 0.25s ease;
  border-bottom: 2px dashed var(--color-primary);
}
.cloze-mask:hover, .cloze-mask.revealed {
  filter: blur(0);
  background-color: rgba(99, 102, 241, 0.2);
  user-select: text;
}

/* 槽位高亮 (Slot Highlights) */
.slot-highlight {
  background-color: var(--color-primary-light);
  color: var(--color-primary);
  padding: 0.1rem 0.35rem;
  border-radius: 0.25rem;
  font-weight: 600;
  border-bottom: 2px dashed var(--color-primary);
  display: inline-block;
}

/* 考研真题英文手写/书信衬线字体渲染 */
.essay-font {
  font-family: var(--font-serif);
  font-size: 1.05rem;
  line-height: 1.75;
}

/* 词数统计徽章动效 */
.word-badge-safe {
  background-color: var(--color-success-light);
  color: var(--color-success);
  border: 1px solid var(--color-success);
}
.word-badge-warn {
  background-color: var(--color-warning-light);
  color: var(--color-warning);
  border: 1px solid var(--color-warning);
}
.word-badge-danger {
  background-color: var(--color-danger-light);
  color: var(--color-danger);
  border: 1px solid var(--color-danger);
}

/* 进度环形进度动画 */
.progress-ring-circle {
  transition: stroke-dashoffset 0.4s ease-in-out;
  transform: rotate(-90deg);
  transform-origin: 50% 50%;
}

/* 弹窗与抽屉 - 去除 backdrop-filter 彻底解决 iPad/iOS WebKit 触摸穿透与点击无反应 Bug */
.modal-backdrop {
  background-color: rgba(15, 23, 42, 0.75);
  transition: opacity 0.2s ease;
  -webkit-tap-highlight-color: transparent;
}

.modal-content-scroll {
  -webkit-overflow-scrolling: touch;
  touch-action: pan-y;
}

/* AI 聊天气泡 */
.chat-bubble-user {
  background-color: var(--color-primary);
  color: #ffffff;
  border-bottom-right-radius: 4px;
}
.chat-bubble-ai {
  background-color: var(--bg-card-sub);
  color: var(--text-main);
  border-bottom-left-radius: 4px;
  border: 1px solid var(--border-color);
}

/* 打字机光标动画 */
.typing-cursor::after {
  content: '▋';
  color: var(--color-primary);
  animation: blink 1s infinite;
  margin-left: 2px;
}
@keyframes blink {
  0%, 100% { opacity: 1; }
  50% { opacity: 0; }
}

/* 移动端触控优化 */
@media (max-width: 640px) {
  .card-flipper {
    min-height: 320px;
  }
  .container {
    padding: 0.75rem;
  }
}