/* ================================================================
   67 论证器 - 全新现代配色方案 & iOS 深色模式兼容
   ================================================================ */

/* === 浅色主题变量（柔和暖色系） === */
:root {
  color-scheme: light;
  --bg: #f2ede8;
  --surface: #faf7f3;
  --surface-alt: #ede6de;
  --surface-hover: #e5ddd3;
  --border: #e0d9d0;
  --border-light: #ede6de;
  --border-input: #d4cdc4;
  --text: #3d362e;
  --text-secondary: #6b6259;
  --text-muted: #a0968c;
  --accent: #7c6ff7;
  --accent-hover: #6558e0;
  --accent-light: #e8e4ff;
  --accent-bg: rgba(124, 111, 247, 0.08);
  --error: #e05555;
  --error-bg: #fdf0f0;
  --success: #3ca07a;
  --shadow: rgba(60, 50, 40, 0.06);
  --shadow-md: rgba(60, 50, 40, 0.1);
  --step-num-bg: #e8e4ff;
  --step-num-color: #7c6ff7;
  --katex-color: #f1f5f9;
}

/* === 深色主题变量 ===
   注意：Safari/Chrome 不需要 color-scheme: dark（iOS WebKit 会根据它
   应用额外暗色滤镜干扰 KaTeX）。但 iOS Edge 浏览器需要 color-scheme: dark
   才能正确显示暗色主题，否则会全黑。通过 .edge-ios class 区分。 */
[data-theme="dark"] {
  --bg: #0f172a;
  --surface: #1e293b;
  --surface-alt: #334155;
  --surface-hover: #475569;
  --border: #334155;
  --border-light: #1e293b;
  --border-input: #475569;
  --text: #f1f5f9;
  --text-secondary: #94a3b8;
  --text-muted: #64748b;
  --accent: #818cf8;
  --accent-hover: #6366f1;
  --accent-light: #312e81;
  --accent-bg: rgba(129, 140, 248, 0.12);
  --error: #f87171;
  --error-bg: rgba(248, 113, 113, 0.1);
  --success: #34d399;
  --shadow: rgba(0, 0, 0, 0.25);
  --shadow-md: rgba(0, 0, 0, 0.4);
  --step-num-bg: #312e81;
  --step-num-color: #818cf8;
  --katex-color: #f1f5f9;
}

/* === 全局重置 === */
* { margin: 0; padding: 0; box-sizing: border-box; }

body {
  font-family: 'Georgia', 'Songti SC', 'SimSun', serif;
  background: var(--bg);
  min-height: 100vh;
  display: flex;
  justify-content: center;
  align-items: center;
  padding: 20px;
  color: var(--text);
  -webkit-text-size-adjust: 100%;
  -webkit-font-smoothing: antialiased;
  -moz-osx-font-smoothing: grayscale;
}

.container {
  max-width: 860px;
  width: 100%;
  position: relative;
  background: var(--surface);
  border: 1px solid var(--border);
  border-radius: 12px;
  padding: 48px 44px;
  box-shadow: 0 1px 3px var(--shadow), 0 8px 32px var(--shadow-md);
}

/* === 语言切换器 === */
.lang-switcher {
  position: absolute;
  top: 16px;
  right: 16px;
  z-index: 10;
  display: flex;
  gap: 8px;
  align-items: flex-start;
}

.switcher-group {
  position: relative;
}

.lang-btn, .theme-btn {
  padding: 6px 14px;
  font-size: 0.78rem;
  background: var(--surface-alt);
  border: 1px solid var(--border-input);
  border-radius: 6px;
  color: var(--text-secondary);
  cursor: pointer;
  font-family: 'Segoe UI', 'Microsoft YaHei', sans-serif;
  transition: all 0.2s ease;
  -webkit-forced-color-adjust: none;
  forced-color-adjust: none;
}

.lang-btn:hover, .theme-btn:hover {
  background: var(--surface-hover);
  color: var(--text);
  border-color: var(--accent);
}

.theme-btn {
  padding: 6px 10px;
  font-size: 0.85rem;
  line-height: 1;
}

.lang-menu {
  position: absolute;
  top: 100%;
  right: 0;
  margin-top: 4px;
  background: var(--surface);
  border: 1px solid var(--border-input);
  border-radius: 6px;
  box-shadow: 0 4px 16px var(--shadow-md);
  overflow: hidden;
  min-width: 90px;
}

.lang-menu-item {
  padding: 8px 14px;
  font-size: 0.82rem;
  color: var(--text-secondary);
  cursor: pointer;
  transition: all 0.15s;
  font-family: 'Segoe UI', 'Microsoft YaHei', sans-serif;
  -webkit-forced-color-adjust: none;
  forced-color-adjust: none;
}

.lang-menu-item:hover {
  background: var(--accent-bg);
  color: var(--accent);
}

.lang-menu-item.active {
  color: var(--accent);
  font-weight: 600;
  background: var(--accent-bg);
}

/* === 高级配置面板 === */
.adv-panel {
  margin-top: 16px;
  padding: 16px;
  background: var(--surface-alt);
  border: 1px solid var(--border);
  border-radius: 8px;
}

.adv-header {
  display: flex;
  justify-content: space-between;
  align-items: center;
  margin-bottom: 8px;
}

.adv-title {
  font-size: 0.85rem;
  font-weight: 600;
  color: var(--text);
  letter-spacing: 1px;
}

.adv-actions { display: flex; gap: 8px; }

.adv-btn {
  padding: 5px 12px;
  font-size: 0.75rem;
  border: 1px solid var(--border-input);
  border-radius: 6px;
  background: var(--surface);
  color: var(--text-secondary);
  cursor: pointer;
  transition: all 0.15s;
  font-family: 'Segoe UI', 'Microsoft YaHei', sans-serif;
}

.adv-btn:hover {
  border-color: var(--accent);
  color: var(--accent);
}

.adv-btn-save {
  background: var(--accent-bg);
  border-color: var(--accent);
  color: var(--accent);
  font-weight: 600;
}

.adv-btn-save:hover {
  background: var(--accent);
  color: #ffffff;
}

.adv-toast {
  margin: 8px 0;
  padding: 6px 12px;
  background: var(--accent-bg);
  border-radius: 6px;
  font-size: 0.75rem;
  color: var(--accent);
  text-align: center;
  font-family: 'Segoe UI', 'Microsoft YaHei', sans-serif;
}

.adv-grid {
  display: grid;
  grid-template-columns: repeat(auto-fill, minmax(200px, 1fr));
  gap: 14px;
  margin-top: 10px;
}

.adv-group {
  display: flex;
  flex-direction: column;
  gap: 8px;
  padding: 10px 12px;
  background: var(--surface);
  border-radius: 6px;
}

.adv-group-title {
  font-size: 0.72rem;
  color: var(--accent);
  letter-spacing: 1px;
  font-weight: 600;
  padding-bottom: 4px;
  border-bottom: 1px solid var(--border-light);
}

.adv-item {
  display: flex;
  flex-direction: column;
  gap: 3px;
}

.adv-item label {
  font-size: 0.72rem;
  color: var(--text-muted);
  font-family: 'Segoe UI', 'Microsoft YaHei', sans-serif;
}

.adv-item input[type="number"] {
  width: 100%;
  padding: 5px 8px;
  font-size: 0.82rem;
  background: var(--surface-alt);
  border: 1px solid var(--border-input);
  border-radius: 6px;
  color: var(--text);
  outline: none;
  transition: all 0.15s;
  font-family: 'Consolas', 'Courier New', monospace;
}

.adv-item input[type="number"]:focus {
  border-color: var(--accent);
  box-shadow: 0 0 0 3px var(--accent-bg);
}

/* === 标题 === */
h1 {
  text-align: center;
  font-size: 1.9rem;
  margin-bottom: 6px;
  color: var(--text);
  font-weight: 700;
  letter-spacing: 1px;
}

.subtitle {
  text-align: center;
  color: var(--text-secondary);
  margin-bottom: 32px;
  font-size: 0.92rem;
  font-family: 'Segoe UI', 'Microsoft YaHei', sans-serif;
}

.num-highlight {
  color: var(--accent);
  font-weight: 700;
}

/* === 输入区 === */
.input-section { margin-bottom: 24px; }

input[type="text"].num-input {
  width: 100%;
  padding: 14px 18px;
  font-size: 1.15rem;
  font-family: 'Consolas', 'Courier New', monospace;
  background: var(--surface-alt);
  border: 1px solid var(--border-input);
  border-radius: 8px;
  color: var(--text);
  outline: none;
  transition: border-color 0.2s, box-shadow 0.2s;
  -webkit-forced-color-adjust: none;
  forced-color-adjust: none;
}

input[type="text"].num-input:focus {
  border-color: var(--accent);
  box-shadow: 0 0 0 3px var(--accent-bg);
}

input[type="text"].num-input::placeholder {
  color: var(--text-muted);
  opacity: 0.6;
}

/* === 切换按钮 === */
.opt-toggle {
  display: flex;
  align-items: center;
  gap: 8px;
  margin-top: 12px;
  flex-wrap: wrap;
}

.opt-label {
  font-size: 0.78rem;
  color: var(--text-secondary);
  letter-spacing: 1px;
  font-family: 'Segoe UI', 'Microsoft YaHei', sans-serif;
}

.opt-sep {
  width: 1px;
  height: 20px;
  background: var(--border-input);
}

.opt-btn {
  padding: 6px 16px;
  font-size: 0.8rem;
  background: var(--surface-alt);
  border: 1px solid var(--border-input);
  border-radius: 6px;
  color: var(--text-muted);
  cursor: pointer;
  transition: all 0.15s;
  font-family: 'Segoe UI', 'Microsoft YaHei', sans-serif;
  -webkit-forced-color-adjust: none;
  forced-color-adjust: none;
}

.opt-btn:hover {
  background: var(--surface-hover);
  border-color: var(--accent);
  color: var(--text);
}

.opt-btn.active {
  background: var(--accent);
  border-color: var(--accent);
  color: #ffffff;
  font-weight: 600;
  -webkit-text-fill-color: #ffffff;
  color-scheme: light;
  -webkit-forced-color-adjust: none;
  forced-color-adjust: none;
}

/* === 结果区 === */
.result-section {
  background: var(--surface-alt);
  border: 1px solid var(--border-light);
  border-radius: 8px;
  padding: 28px;
  min-height: 180px;
  display: flex;
  flex-direction: column;
  justify-content: center;
}

.result-title {
  font-size: 0.78rem;
  color: var(--text-secondary);
  margin-bottom: 12px;
  text-transform: uppercase;
  letter-spacing: 2px;
  font-family: 'Segoe UI', 'Microsoft YaHei', sans-serif;
}

/* ================================================================
   表达式展示框 - 核心区域
   集成 iOS 兼容：锁定 light color-scheme + 阻止 iOS 滤镜
   ================================================================ */
.expression-box {
  min-height: 60px;
  padding: 20px 28px;
  border-radius: 6px;
  display: block;
  text-align: center;
  white-space: nowrap;
  overflow-x: auto;
  line-height: 1.6;

  /* 跟随主题：亮色浅底 + 深色文字 / 暗色深底 + 浅色文字 */
  background: var(--surface-alt);
  background-color: var(--surface-alt);
  border: 1px solid var(--border);
  color: var(--text);

  /* iOS WebKit 关键防护：显式锁定 light 颜色方案 */
  color-scheme: light !important;
  -webkit-color-scheme: light !important;

  /* 阻止 iOS Safari 应用任何颜色滤镜 */
  -webkit-filter: none !important;
  filter: none !important;

  /* 阻止系统强制调整颜色 */
  -webkit-forced-color-adjust: none !important;
  forced-color-adjust: none !important;
}

.expression-box::-webkit-scrollbar { height: 6px; }
.expression-box::-webkit-scrollbar-track {
  background: var(--surface-hover);
  border-radius: 3px;
}
.expression-box::-webkit-scrollbar-thumb {
  background: var(--accent-light);
  border-radius: 3px;
}
.expression-box::-webkit-scrollbar-thumb:hover {
  background: var(--accent);
}

.expression-box.pulse { animation: pulse 0.6s ease-out; }

.expression-box.loading {
  opacity: 0.45;
  transition: opacity 0.15s ease;
  pointer-events: none;
}

@keyframes pulse {
  0% { background: var(--surface-hover); }
  100% { background: var(--surface-alt); }
}

/* 占位文本样式 */
.expression-text {
  font-family: 'Consolas', 'Courier New', monospace;
  font-size: 1.05rem;
  color: var(--text-muted);
  text-align: center;
}

/* === 加载 === */
.loading { text-align: center; padding: 20px; }

.spinner {
  width: 36px;
  height: 36px;
  border: 3px solid var(--border-light);
  border-top-color: var(--accent);
  border-radius: 50%;
  animation: spin 0.7s linear infinite;
  margin: 0 auto 12px;
}

@keyframes spin { to { transform: rotate(360deg); } }

/* === 统计 === */
.stats {
  margin-top: 16px;
  display: flex;
  gap: 24px;
  flex-wrap: wrap;
  justify-content: center;
}

.stat {
  font-size: 0.82rem;
  color: var(--text-secondary);
  font-family: 'Segoe UI', 'Microsoft YaHei', sans-serif;
}

.stat span {
  color: var(--accent);
  font-weight: 600;
  margin: 0 3px;
}

/* === 步骤 === */
.steps-collapse {
  margin-top: 14px;
  text-align: center;
  cursor: pointer;
  user-select: none;
  padding: 8px;
  border-radius: 6px;
  transition: background 0.15s;
}

.steps-collapse:hover {
  background: var(--surface-hover);
}

.steps-toggle {
  font-size: 0.82rem;
  color: var(--accent);
  letter-spacing: 1px;
  font-family: 'Segoe UI', 'Microsoft YaHei', sans-serif;
}

.steps-detail {
  margin-top: 10px;
  padding: 16px;
  background: var(--surface);
  border: 1px solid var(--border-light);
  border-radius: 6px;
}

/* 步骤展开/收起滑动动画 */
.slide-down-enter-active {
  transition: all 0.3s ease-out;
  overflow: hidden;
}
.slide-down-leave-active {
  transition: all 0.25s ease-in;
  overflow: hidden;
}
.slide-down-enter-from {
  max-height: 0;
  opacity: 0;
  margin-top: 0;
  padding-top: 0;
  padding-bottom: 0;
  border-width: 0;
}
.slide-down-leave-to {
  max-height: 0;
  opacity: 0;
  margin-top: 0;
  padding-top: 0;
  padding-bottom: 0;
  border-width: 0;
}

.steps-list { display: flex; flex-direction: column; gap: 4px; }

.step-item {
  display: flex;
  align-items: baseline;
  gap: 10px;
  padding: 6px 10px;
  background: var(--surface-alt);
  border-radius: 4px;
}

.step-num {
  flex-shrink: 0;
  width: 22px;
  height: 22px;
  background: var(--step-num-bg);
  color: var(--step-num-color);
  border-radius: 50%;
  display: flex;
  align-items: center;
  justify-content: center;
  font-size: 0.7rem;
  font-weight: 600;
  font-family: 'Segoe UI', sans-serif;
}

.step-desc {
  font-family: 'Consolas', 'Courier New', monospace;
  font-size: 0.82rem;
  color: var(--text);
  word-break: break-all;
}

.steps-meta {
  margin-top: 10px;
  display: flex;
  gap: 16px;
  justify-content: flex-end;
  font-size: 0.72rem;
  color: var(--text-secondary);
  font-family: 'Segoe UI', 'Microsoft YaHei', sans-serif;
}

/* === 运算符解释 === */
.op-legend {
  margin-top: 14px;
  padding-top: 14px;
  border-top: 1px solid var(--border-light);
}

.op-legend-title {
  font-size: 0.72rem;
  color: var(--text-secondary);
  margin-bottom: 8px;
  letter-spacing: 1px;
  font-family: 'Segoe UI', 'Microsoft YaHei', sans-serif;
}

.op-legend-item {
  display: flex;
  align-items: baseline;
  gap: 10px;
  padding: 3px 0;
}

.op-symbol {
  flex-shrink: 0;
  min-width: 70px;
  font-family: 'Consolas', 'Courier New', monospace;
  font-size: 0.78rem;
  color: var(--accent);
  font-weight: 600;
}

.op-explain {
  font-size: 0.76rem;
  color: var(--text-muted);
  font-family: 'Segoe UI', 'Microsoft YaHei', sans-serif;
}

/* === 复制按钮 === */
.copy-section {
  margin-top: 14px;
  padding-top: 14px;
  border-top: 1px solid var(--border-light);
  display: flex;
  gap: 8px;
  justify-content: flex-end;
}

.copy-btn {
  padding: 6px 16px;
  font-size: 0.78rem;
  background: var(--surface-alt);
  border: 1px solid var(--border-input);
  border-radius: 6px;
  color: var(--text-secondary);
  cursor: pointer;
  transition: all 0.15s;
  font-family: 'Segoe UI', 'Microsoft YaHei', sans-serif;
}

.copy-btn:hover {
  background: var(--accent-bg);
  border-color: var(--accent);
  color: var(--accent);
}

/* === 错误 === */
.error {
  color: var(--error);
  text-align: center;
  padding: 12px;
  font-size: 0.9rem;
  font-family: 'Segoe UI', 'Microsoft YaHei', sans-serif;
}

/* === 示例标签 === */
.examples {
  margin-top: 20px;
  display: flex;
  gap: 8px;
  flex-wrap: wrap;
  align-items: center;
}

.examples-label {
  font-size: 0.85rem;
  color: var(--text-secondary);
  font-family: 'Segoe UI', 'Microsoft YaHei', sans-serif;
}

.example-tag {
  padding: 5px 14px;
  background: var(--surface-alt);
  border-radius: 6px;
  cursor: pointer;
  font-size: 0.82rem;
  transition: all 0.15s;
  border: 1px solid var(--border-input);
  color: var(--text-muted);
  font-family: 'Consolas', 'Courier New', monospace;
}

.example-tag:hover {
  background: var(--accent-bg);
  border-color: var(--accent);
  color: var(--accent);
}

/* === 页脚 === */
.footer {
  margin-top: 24px;
  text-align: center;
  padding-top: 16px;
  border-top: 1px solid var(--border-light);
}

.github-link {
  display: inline-flex;
  align-items: center;
  gap: 8px;
  padding: 8px 16px;
  font-size: 0.82rem;
  color: var(--text-secondary);
  text-decoration: none;
  border-radius: 6px;
  transition: all 0.15s;
  font-family: 'Segoe UI', 'Microsoft YaHei', sans-serif;
}

.github-link:hover {
  color: var(--accent);
  background: var(--accent-bg);
}

.github-link i { font-size: 1.1rem; }

/* === 移动端响应式 === */
@media (max-width: 600px) {
  body { padding: 12px; }
  .container { padding: 32px 20px 28px; border-radius: 8px; }
  .lang-switcher { top: 12px; right: 12px; }
  h1 { font-size: 1.5rem; }
  .subtitle { font-size: 0.82rem; margin-bottom: 20px; }
  .result-section { padding: 20px 16px; min-height: 150px; }
  .expression-box { padding: 16px 20px; }
  .expression-box .katex { font-size: 1.05rem; }
  input[type="text"].num-input { padding: 12px 14px; font-size: 1.05rem; }
  .stats { gap: 14px; }
  .stat { font-size: 0.78rem; }
  .steps-detail { padding: 12px; }
  .copy-section { flex-wrap: wrap; }
  .adv-grid {
    grid-template-columns: 1fr;
  }
}

/* === iOS 安全区域支持 === */
@supports (padding: max(0px)) {
  body {
    padding-left: max(20px, env(safe-area-inset-left));
    padding-right: max(20px, env(safe-area-inset-right));
    padding-top: max(20px, env(safe-area-inset-top));
    padding-bottom: max(20px, env(safe-area-inset-bottom));
  }
}

/* ================================================================
   iOS 系统深色模式兼容

   根策略：Safari/Chrome 使用 color-scheme: light（显式颜色变量实现暗色外观）。
   Edge iOS 浏览器需要 color-scheme: dark（否则暗色下全黑）。
   通过 JS 检测 Edge 后添加 .edge-ios class 到 <html>。
   expression-box 始终有 color-scheme: light !important 保护 KaTeX。
   ================================================================ */
/* iOS 防护属性已合并到 .expression-box 主规则中 */

/* --- Edge iOS 浏览器专属：恢复 color-scheme: dark --- */
:root.edge-ios[data-theme="dark"] {
  color-scheme: dark;
}

/* ================================================================
   深色模式自动回退（系统深色且未强制浅色时）

   注意：Safari/Chrome 不设 color-scheme: dark。Edge iOS 另外添加。
   ================================================================ */
@media (prefers-color-scheme: dark) {
  :root:not([data-theme="light"]) {
    --bg: #0f172a;
    --surface: #1e293b;
    --surface-alt: #334155;
    --surface-hover: #475569;
    --border: #334155;
    --border-light: #1e293b;
    --border-input: #475569;
    --text: #f1f5f9;
    --text-secondary: #94a3b8;
    --text-muted: #64748b;
    --accent: #818cf8;
    --accent-hover: #6366f1;
    --accent-light: #312e81;
    --accent-bg: rgba(129, 140, 248, 0.12);
    --error: #f87171;
    --error-bg: rgba(248, 113, 113, 0.1);
    --success: #34d399;
    --shadow: rgba(0, 0, 0, 0.25);
    --shadow-md: rgba(0, 0, 0, 0.4);
    --step-num-bg: #312e81;
    --step-num-color: #818cf8;
    --katex-color: #f1f5f9;
  }

  /* Edge iOS 系统深色 + 未设浅色主题 → 恢复 color-scheme: dark */
  :root.edge-ios:not([data-theme="light"]) {
    color-scheme: dark;
  }
}

/* === 过渡效果 === */
:root,
[data-theme="dark"] {
  transition: background-color 0.3s ease, color 0.3s ease;
}

body,
.container,
.result-section,
.expression-box,
input[type="text"].num-input,
.adv-panel,
.lang-menu,
.steps-detail,
.step-item {
  transition: background-color 0.3s ease, border-color 0.3s ease, color 0.3s ease;
}