/*!
 * TeachAny AI 学伴悬浮球样式（v7.0）
 * 左下角 FAB + API Key 配置 Modal + 问答对话面板 + 语言切换
 *
 * 使用方式：
 *   <link rel="stylesheet" href="./ai-tutor.css">
 *   <script src="./ai-tutor.js" defer></script>
 *   <script>window.__TEACHANY_TUTOR_CONFIG__ = { ... };</script>
 *
 * 设计原则：
 *   - 不依赖任何外部 CSS 框架
 *   - 所有颜色通过 CSS 变量可被学段模板覆盖
 *   - z-index 9998/9999 高于所有业务内容（音频条 100-200）
 */

/* ═══ CSS 变量（可被课件学段模板覆盖） ═══ */
:root {
  --tutor-primary: #6366f1;        /* 靛青主色 */
  --tutor-primary-dark: #4f46e5;
  --tutor-accent: #ec4899;         /* 粉色点缀 */
  --tutor-bg: #ffffff;
  --tutor-bg-soft: #f8fafc;
  --tutor-border: #e2e8f0;
  --tutor-text: #1e293b;
  --tutor-text-soft: #64748b;
  --tutor-bubble-ai: #eef2ff;
  --tutor-bubble-user: #6366f1;
  --tutor-bubble-user-text: #ffffff;
  --tutor-shadow: 0 20px 40px -12px rgba(99, 102, 241, 0.35);
}

/* ═══ FAB 悬浮球（v6.11 起改为左下角，避开右下 TTS 控制器） ═══ */
.ai-tutor-fab {
  position: fixed;
  left: 24px;
  bottom: 24px;
  width: 56px;
  height: 56px;
  border-radius: 50%;
  background: linear-gradient(135deg, var(--tutor-primary), var(--tutor-accent));
  color: #fff;
  display: flex;
  align-items: center;
  justify-content: center;
  font-size: 28px;
  cursor: pointer;
  box-shadow: var(--tutor-shadow);
  z-index: 9998;
  transition: transform .2s ease, box-shadow .2s ease;
  border: none;
  user-select: none;
}
.ai-tutor-fab:hover {
  transform: translateY(-3px) scale(1.05);
  box-shadow: 0 28px 50px -12px rgba(99, 102, 241, 0.55);
}
.ai-tutor-fab.has-unread::after {
  content: "";
  position: absolute;
  top: 8px;
  right: 8px;
  width: 10px;
  height: 10px;
  border-radius: 50%;
  background: #f59e0b;
  border: 2px solid #fff;
}

/* ═══ Modal 遮罩（Key 配置时使用） ═══ */
.ai-tutor-mask {
  position: fixed;
  inset: 0;
  background: rgba(15, 23, 42, 0.55);
  backdrop-filter: blur(4px);
  z-index: 9999;
  display: flex;
  align-items: center;
  justify-content: center;
  padding: 20px;
}

/* ═══ API Key 配置弹窗 ═══ */
.ai-tutor-config {
  background: var(--tutor-bg);
  border-radius: 20px;
  padding: 28px;
  width: min(440px, 100%);
  box-shadow: 0 30px 60px -20px rgba(15, 23, 42, 0.35);
  color: var(--tutor-text);
  font-family: system-ui, -apple-system, "Helvetica Neue", sans-serif;
}
.ai-tutor-config h2 {
  margin: 0 0 6px 0;
  font-size: 20px;
  font-weight: 700;
  background: linear-gradient(135deg, var(--tutor-primary), var(--tutor-accent));
  -webkit-background-clip: text;
  background-clip: text;
  color: transparent;
}
.ai-tutor-config .subtitle {
  margin: 0 0 18px 0;
  font-size: 13px;
  color: var(--tutor-text-soft);
  line-height: 1.5;
}
.ai-tutor-config label {
  display: block;
  font-size: 13px;
  font-weight: 600;
  margin: 12px 0 6px 0;
  color: var(--tutor-text);
}
.ai-tutor-config input,
.ai-tutor-config select {
  width: 100%;
  padding: 10px 12px;
  border: 1.5px solid var(--tutor-border);
  border-radius: 10px;
  font-size: 14px;
  font-family: inherit;
  color: var(--tutor-text);
  background: var(--tutor-bg-soft);
  transition: border-color .15s ease;
  box-sizing: border-box;
}
.ai-tutor-config input:focus,
.ai-tutor-config select:focus {
  outline: none;
  border-color: var(--tutor-primary);
}
.ai-tutor-config .privacy {
  margin: 14px 0 4px 0;
  font-size: 12px;
  color: var(--tutor-text-soft);
  padding: 10px 12px;
  background: #fef3c7;
  border-left: 3px solid #f59e0b;
  border-radius: 6px;
  line-height: 1.55;
}
.ai-tutor-config .actions {
  margin-top: 20px;
  display: flex;
  gap: 10px;
  justify-content: flex-end;
}
.ai-tutor-config button {
  padding: 10px 18px;
  border-radius: 10px;
  font-size: 14px;
  font-weight: 600;
  cursor: pointer;
  border: none;
  font-family: inherit;
  transition: transform .15s ease, box-shadow .15s ease;
}
.ai-tutor-config .btn-cancel {
  background: var(--tutor-bg-soft);
  color: var(--tutor-text-soft);
  border: 1px solid var(--tutor-border);
}
.ai-tutor-config .btn-save {
  background: linear-gradient(135deg, var(--tutor-primary), var(--tutor-primary-dark));
  color: #fff;
  box-shadow: 0 8px 16px -8px rgba(99, 102, 241, 0.6);
}
.ai-tutor-config .btn-save:hover {
  transform: translateY(-1px);
}
.ai-tutor-config .btn-save:disabled {
  opacity: .5;
  cursor: not-allowed;
  transform: none;
}

/* ═══ 对话面板（v6.11 起改为左下角，与 FAB 一致） ═══ */
.ai-tutor-panel {
  position: fixed;
  left: 24px;
  bottom: 96px;
  width: 360px;
  height: 520px;
  max-width: calc(100vw - 48px);
  max-height: calc(100vh - 120px);
  background: var(--tutor-bg);
  border-radius: 18px;
  box-shadow: 0 24px 48px -16px rgba(15, 23, 42, 0.32);
  z-index: 9998;
  display: flex;
  flex-direction: column;
  overflow: hidden;
  font-family: system-ui, -apple-system, "Helvetica Neue", sans-serif;
  color: var(--tutor-text);
  transform: translateY(16px);
  opacity: 0;
  pointer-events: none;
  transition: opacity .18s ease, transform .18s ease;
}
.ai-tutor-panel.open {
  opacity: 1;
  transform: translateY(0);
  pointer-events: auto;
}

/* 面板头部 */
.ai-tutor-header {
  padding: 14px 16px;
  background: linear-gradient(135deg, var(--tutor-primary), var(--tutor-accent));
  color: #fff;
  display: flex;
  align-items: center;
  gap: 10px;
}
.ai-tutor-header .title {
  flex: 1;
  font-size: 14px;
  font-weight: 600;
  line-height: 1.3;
}
.ai-tutor-header .title .subtitle {
  display: block;
  font-size: 11px;
  font-weight: 400;
  opacity: .85;
  margin-top: 2px;
}
.ai-tutor-header button {
  background: rgba(255,255,255,.2);
  color: #fff;
  border: none;
  border-radius: 6px;
  padding: 4px 10px;
  font-size: 12px;
  cursor: pointer;
  font-family: inherit;
}
.ai-tutor-header button:hover {
  background: rgba(255,255,255,.32);
}
/* 语言切换按钮 */
.ai-tutor-header .btn-lang {
  font-weight: 700;
  font-size: 12px;
  min-width: 32px;
  text-align: center;
  letter-spacing: .5px;
}
/* 设置按钮 */
.ai-tutor-header .btn-settings {
  font-size: 14px;
  padding: 4px 8px;
}

/* 上下文条（显示当前学习 section） */
.ai-tutor-context-bar {
  padding: 8px 14px;
  background: var(--tutor-bg-soft);
  border-bottom: 1px solid var(--tutor-border);
  font-size: 11px;
  color: var(--tutor-text-soft);
  display: flex;
  align-items: center;
  gap: 6px;
  line-height: 1.4;
}
.ai-tutor-context-bar .pill {
  background: var(--tutor-primary);
  color: #fff;
  padding: 2px 8px;
  border-radius: 10px;
  font-weight: 600;
  font-size: 10px;
}

/* 消息区 */
.ai-tutor-messages {
  flex: 1;
  overflow-y: auto;
  padding: 14px;
  display: flex;
  flex-direction: column;
  gap: 10px;
  background: var(--tutor-bg);
}
.ai-tutor-messages::-webkit-scrollbar { width: 6px; }
.ai-tutor-messages::-webkit-scrollbar-thumb {
  background: var(--tutor-border);
  border-radius: 3px;
}
.ai-tutor-bubble {
  max-width: 82%;
  padding: 9px 13px;
  border-radius: 14px;
  font-size: 13.5px;
  line-height: 1.6;
  word-wrap: break-word;
  white-space: pre-wrap;
}
.ai-tutor-bubble.ai {
  align-self: flex-start;
  background: var(--tutor-bubble-ai);
  color: var(--tutor-text);
  border-bottom-left-radius: 4px;
}
.ai-tutor-bubble.user {
  align-self: flex-end;
  background: var(--tutor-bubble-user);
  color: var(--tutor-bubble-user-text);
  border-bottom-right-radius: 4px;
}
.ai-tutor-bubble.error {
  align-self: stretch;
  background: #fef2f2;
  color: #b91c1c;
  border: 1px solid #fecaca;
  font-size: 12px;
}
.ai-tutor-bubble.loading::after {
  content: "●";
  display: inline-block;
  animation: ai-tutor-blink 1.2s infinite;
  margin-left: 4px;
}
@keyframes ai-tutor-blink {
  0%, 100% { opacity: .3; }
  50% { opacity: 1; }
}

/* 输入区 */
.ai-tutor-input-wrap {
  border-top: 1px solid var(--tutor-border);
  padding: 10px;
  display: flex;
  gap: 8px;
  align-items: flex-end;
  background: var(--tutor-bg);
}
.ai-tutor-input-wrap textarea {
  flex: 1;
  resize: none;
  border: 1.5px solid var(--tutor-border);
  border-radius: 10px;
  padding: 8px 12px;
  font-size: 13.5px;
  font-family: inherit;
  color: var(--tutor-text);
  background: var(--tutor-bg-soft);
  max-height: 100px;
  line-height: 1.4;
  min-height: 36px;
  box-sizing: border-box;
}
.ai-tutor-input-wrap textarea:focus {
  outline: none;
  border-color: var(--tutor-primary);
}
.ai-tutor-input-wrap button {
  height: 36px;
  min-width: 54px;
  border: none;
  border-radius: 10px;
  background: linear-gradient(135deg, var(--tutor-primary), var(--tutor-primary-dark));
  color: #fff;
  font-size: 13px;
  font-weight: 600;
  cursor: pointer;
  font-family: inherit;
  transition: transform .15s;
}
.ai-tutor-input-wrap button:hover:not(:disabled) {
  transform: translateY(-1px);
}
.ai-tutor-input-wrap button:disabled {
  opacity: .5;
  cursor: not-allowed;
}

/* 移动端适配（v6.11 左下角） */
@media (max-width: 560px) {
  .ai-tutor-panel {
    left: 12px;
    bottom: 84px;
    width: calc(100vw - 24px);
    height: calc(100vh - 120px);
    max-height: 560px;
  }
  .ai-tutor-fab {
    left: 16px;
    bottom: 16px;
  }
}

/* 深色学段（高中）兼容 */
@media (prefers-color-scheme: dark) {
  :root {
    --tutor-bg: #1e293b;
    --tutor-bg-soft: #0f172a;
    --tutor-border: #334155;
    --tutor-text: #f1f5f9;
    --tutor-text-soft: #94a3b8;
    --tutor-bubble-ai: #334155;
  }
}

/* v7.7: 底部音频播放条出现时，FAB 自动上移避开 */
body.tap-bar-on .ai-tutor-fab,
body.audio-playing .ai-tutor-fab {
  bottom: 100px;
  transition: bottom 0.25s ease;
}

/* v7.7: 同时，tutor-card section 应在课件靠前位置；此规则只是视觉兜底 */
#teachany-ai-tutor-card {
  scroll-margin-top: 80px;
}