/* =========================================
   1. 基础配置 (Design Tokens & Reset)
   ========================================= */
:root {
  font-size: 14px;

  /* 精简、克制的色彩系统 —— 仅保留必要语义色 */
  --bg-main: #0a0c10;        /* 主背景，更深沉 */
  --bg-sec: #151b23;         /* 次级背景 */
  --bg-elevated: #1e262f;    /* 浮层/卡片背景 */
  --border-muted: #2d343b;   /* 边框色，低饱和 */
  --text-primary: #e6edf3;   /* 主文字 */
  --text-secondary: #b1bac4; /* 辅助文字 */
  --text-muted: #848d974e;     /* 禁用/提示文字 */
  --accent-blue: #2f81f7;    /* 主操作、链接 */
  --accent-green: #2ea043;   /* 正确、进度、开始 */
  --accent-red: #da3633;     /* 错误、重置、结束 */
  --accent-gray: #565f6b;    /* 次要按钮、展开、折叠 */
  --shadow-sm: 0 1px 2px rgba(0,0,0,0.5);
  --radius-md: 0.5rem;
  --radius-lg: 0.75rem;
}

/* 响应式字体缩放（保持原逻辑） */
@media (min-width: 600px) { :root { font-size: 15px; } }
@media (min-width: 1024px) { :root { font-size: 16px; } }
@media (min-width: 1200px) { :root { font-size: 18px; } }
@media (min-width: 1600px) { :root { font-size: 20px; } }
@media (min-width: 1920px) { :root { font-size: 24px; } }

* {
  box-sizing: border-box;
}

body {
  font-family: 'Noto Sans SC', -apple-system, BlinkMacSystemFont, sans-serif;
  background: var(--bg-main);
  color: var(--text-primary);
  margin: 0;
  padding: 0 0.5rem;
  line-height: 1.5;
  overflow-x: hidden;
}

/* =========================================
   2. 顶部固定栏 (Top Bar) —— 极简留白
   ========================================= */
#top-fixed-bar {
  position: sticky;
  top: 0;
  z-index: 1000;
  background: var(--bg-main);
  border-bottom: 1px solid var(--border-muted);
  padding: 0.6rem 0.25rem;
  display: flex;
  flex-direction: column;
  gap: 0.5rem;
  backdrop-filter: blur(4px); /* 轻量玻璃效果 */
}

.top-row-stats {
  display: flex;
  align-items: center;
  justify-content: space-between;
  flex-wrap: wrap;
  gap: 0.5rem;
}

.top-btn-group {
  display: flex;
  gap: 0.5rem;
}

/* =========================================
   3. 通用按钮 —— 统一基底，克制用色
   ========================================= */
.btn-common {
  padding: 0.4rem 1rem;
  border-radius: var(--radius-md);
  border: 1px solid transparent;
  background: var(--bg-sec);
  color: var(--text-primary);
  font-size: 0.9rem;
  font-weight: 500;
  cursor: pointer;
  transition: all 0.1s ease;
  box-shadow: var(--shadow-sm);
  display: inline-flex;
  align-items: center;
  justify-content: center;
  line-height: 1.4;
}

.btn-common:hover {
  background: #2d3748;
  border-color: var(--border-muted);
}

.btn-common:active {
  transform: translateY(1px);
  box-shadow: none;
}

/* 主要操作 —— 蓝 */
#btn-to-play,
#btn-next-q,
#btn-diff-toggle.confirm-mode {
  background: var(--accent-blue) !important;
  border-color: #1f5f9e !important;
  color: white !important;
}
#btn-to-play:hover,
#btn-next-q:hover,
#btn-diff-toggle.confirm-mode:hover {
  background: #3c8df5 !important;
}

/* 危险/重置 —— 红 */
#action-clear-data,
#practice-footer-nav button[onclick="UI.closeL2()"],
#btn-redo-wrong {
  background: var(--accent-red) !important;
  border-color: #a52a2a !important;
  color: white !important;
}
#action-clear-data:hover,
#practice-footer-nav button[onclick="UI.closeL2()"]:hover,
#btn-redo-wrong:hover {
  background: #e04b4b !important;
}

/* 次要操作 —— 灰 */
#btn-to-know,
#btn-to-list,
.c-btn,
.l-btn,
#btn-toggle-all {
  background: var(--accent-gray) !important;
  border-color: #3d4a5a !important;
  color: white !important;
}
#btn-to-know:hover,
#btn-to-list:hover,
.c-btn:hover,
.l-btn:hover,
#btn-toggle-all:hover {
  background: #6a7a8c !important;
}

/* 调试按钮保持低调 */
.debug-btn {
  background: #2d3748 !important;
  border-color: #4a5568 !important;
  color: var(--text-secondary) !important;
}

/* =========================================
   4. 难度筛选 —— 清晰、无干扰
   ========================================= */
#difficulty-bar-root {
  display: flex;
  align-items: center;
  gap: 1rem;
  width: 100%;
  background: var(--bg-sec);
  padding: 0.5rem 0.75rem;
  border-radius: var(--radius-lg);
  border: 1px solid var(--border-muted);
}

#diff-view-mode {
  font-size: 0.9rem;
  color: var(--text-secondary);
  white-space: nowrap;
}

#diff-current-text {
  color: var(--accent-blue);
  font-weight: 600;
}

#diff-selection-area {
  display: flex;
  flex-wrap: wrap;
  gap: 0.5rem;
  flex: 1;
}

.diff-item-btn {
  padding: 0.2rem 1rem;
  border: 1px solid var(--border-muted);
  background: #1c2530;
  color: var(--text-secondary);
  border-radius: 30px;        /* 胶囊样式，更柔和 */
  cursor: pointer;
  font-size: 0.85rem;
  transition: 0.1s;
}

.diff-item-btn.selected {
  background: rgba(47, 129, 247, 0.2) !important;
  color: var(--accent-blue);
  border-color: var(--accent-blue);
  font-weight: 600;
}

#btn-diff-toggle {
  min-width: 6rem;
  background: #2d3748;
  border-color: var(--border-muted);
}

/* =========================================
   5. 表格主内容 —— 呼吸感、层级清晰
   ========================================= */
#main-content-wrapper {
  padding: 0.75rem 0.25rem;
}

#data-table-root {
  width: 100%;
  border-collapse: collapse;
  font-size: 0.9rem;
  table-layout: fixed;
}

#dom-row-global {font-style: italic underline;background-color:#003333}

/* 表头 */
.row-base th {
  padding: 0.75rem 0.5rem;
  font-weight: 600;
  color: var(--text-secondary);
  border-bottom: 2px solid var(--border-muted);
  text-align: center;
}

/* 单元格统一样式 */
.row-base td {
  padding: 0.75rem 0.5rem;
  border-bottom: 1px solid var(--border-muted);
  vertical-align: middle;
}

/* 数字统计区域 */
.c-tot, .c-ok, .c-err, .c-rem {
  font-weight: 600;
  text-align: center;
}

.stat-zero {
  color: var(--text-muted) !important;
  font-weight: 400 !important;
}

.stat-ok-active {
  color: var(--accent-green) !important;
}

.stat-err-active {
  color: var(--accent-red) !important;
}

.stat-rem-active {
  color: var(--accent-blue) !important;
}

/* 层级缩进 & 视觉区分 */
/* --- 一级 (T1): 根容器，背景最深，强调稳重 --- */
.row-t1 {
  background-color: #0d1117;
  color: #f0f6fc;
  font-weight: 600;
  border-bottom: 0.07rem solid #30363d;
  padding: 0.8rem 1.1rem;
}

/* --- 二级 (T2): 过渡层，线条纤细，色调低调 --- */
.row-t2 {
  background-color: #161b22;
  color: #c9d1d9;
  /* 视觉点：极细的深灰色左边框，起辅助作用 */
  border-left: 0.3rem solid #0272fa; 
  padding: 0.6rem 1.1rem 0.6rem 0rem; /* 增加左缩进 */
  margin: 0.07rem 0;
  font-size: 0.95rem;
}

/* --- 三级 (T3): 重点操作层，线条加粗，颜色明亮 --- */
.row-t3 {
  background-color: #21262d; /* 最高的视觉抬升感 */
  color: #58a6ff; /* 文字使用浅蓝色，提示可交互 */
  /* 视觉点：明显的粗边框，使用品牌亮蓝色 */
  border-left: 0.3rem solid #ff6f00; 
  padding: 0.5rem 1.1rem 0.5rem 0rem; /* 深度缩进 */
  margin: 0.07rem 0;
  font-size: 0.9rem;
}

.row-t1 .c-name {
  font-weight: 700;
  font-size: 1rem;
  color: var(--text-primary);
}

.row-t2 .c-name {
  padding-left: 1.2rem;
  font-weight: 600;
  color: var(--text-secondary);
}

.row-t3 .c-name {
  padding-left: 2rem;
  color: #b7b7b8;
  font-weight: 400;
}
/* 展开按钮单元格居中对齐 */
.c-btn-td, .td-btn {
  text-align: center;
}

/* 激活状态（关闭）按钮 */
.btn-active-close {
  background: #c30f0f !important;
  opacity: 0.9;
}

/* 行动面板 —— 卡片形式，无边框跳跃 */
.action-panel-row td {
  background: var(--bg-sec) !important;
  padding: 1.2rem 1rem !important;
  border-top: 1px dashed var(--border-muted);
  border-bottom: 1px dashed var(--border-muted);
}

/* =========================================
   6. 弹窗 & 模态层 —— 聚焦内容
   ========================================= */
#overlay-level-1,
#overlay-level-2 {
  position: fixed;
  inset: 0;
  background: rgba(0, 0, 0, 0.8);
  backdrop-filter: blur(6px);
  display: none;
  justify-content: center;
  align-items: center;
  z-index: 2000;
}

#modal-box-l1,
#modal-box-l2 {
  background: var(--bg-main);
  width: 95%;
  height: 90%;
  border-radius: var(--radius-lg);
  border: 1px solid var(--border-muted);
  display: flex;
  flex-direction: column;
  overflow: hidden;
  box-shadow: 0 12px 28px rgba(0,0,0,0.7);
}

/* =========================================
   7. 列表视图 (查看已做) —— 简洁分页
   ========================================= */
#list-view-container {
  padding: 1.5rem;
  overflow-y: auto;
}

#list-filter-ctrl {
  display: flex;
  gap: 1.5rem;
  align-items: center;
  margin-bottom: 1.5rem;
  padding: 0.75rem;
  background: var(--bg-elevated);
  border-radius: var(--radius-md);
}

#list-filter-ctrl select {
  background: #1c2530;
  border: 1px solid var(--border-muted);
  color: var(--text-primary);
  padding: 0.3rem 1.5rem 0.3rem 0.8rem;
  border-radius: 30px;
  font-size: 0.9rem;
}

#list-pagination {
  display: flex;
  justify-content: center;
  align-items: center;
  gap: 1.2rem;
  margin: 1.5rem 0;
}

#page-info {
  color: var(--text-secondary);
  font-size: 0.9rem;
}

/* 列表表格 */
#list-table-body .row-base td {
  padding: 0.6rem 0.5rem;
}

.l-stat {
  font-weight: 700;
  text-align: center;
}

/* =========================================
   8. 练习界面 —— 干净、留白、易读
   ========================================= */
#practice-scroll-area {
  flex: 1;
  overflow-y: auto;
  padding: 2rem;
}

#progress-bar-container {
  height: 0.4rem;
  background: #2a343e;
  border-radius: 20px;
  overflow: hidden;
  margin: 0.8rem 0;
}

#progress-bar-fill {
  height: 100%;
  background: var(--accent-green);
  transition: width 0.2s;
  border-radius: 20px;
}

#question-title-text {
  font-size: 1.3rem;
  font-weight: 600;
  margin: 1.5rem 0 1.2rem;
  color: var(--text-primary);
  line-height: 1.4;
}

.option-box {
  margin: 0.8rem 0;
  padding: 1.1rem 1.2rem;
  border: 1px solid var(--border-muted);
  border-radius: var(--radius-md);
  background: var(--bg-sec);
  cursor: pointer;
  transition: background 0.15s, border-color 0.15s;
  color: var(--text-primary);
}

.option-box:hover {
  background: #222c36;
  border-color: var(--accent-blue);
}

/* 已答选项：视觉弱化，但保留正确答案高亮（内联样式覆盖） */
.option-disabled {
  opacity: 0.85;
  cursor: default;
  pointer-events: none;
}

#explain-panel {
  margin-top: 2rem;
  padding: 1.5rem;
  background: #0f151c;
  border-radius: var(--radius-md);
  border-left: 4px solid var(--accent-blue);
}

#text-explain-main {
  font-size: 1rem;
  font-weight: 500;
  color: #d4dfe8;
  margin-bottom: 1rem;
}

#text-explain-detail {
  font-size: 0.9rem;
  color: var(--text-secondary);
  line-height: 1.6;
}

#practice-footer-nav {
  padding: 1.2rem 1.5rem;
  display: flex;
  gap: 1rem;
  background: var(--bg-sec);
  border-top: 1px solid var(--border-muted);
}

#practice-footer-nav .btn-common {
  font-size: 1.1rem !important;
  font-weight: 600 !important;
  padding: 0.7rem 0.8rem;
  flex: 1;
}

/* =========================================
   9. 知识点视图 —— 舒适阅读
   ========================================= */
#knowledge-view-container {
  padding: 2rem;
  overflow-y: auto;
}

#knowledge-view-title {
  font-size: 1.6rem;
  font-weight: 700;
  color: var(--accent-blue);
  border-bottom: 2px solid var(--border-muted);
  padding-bottom: 0.8rem;
  margin-bottom: 1.8rem;
}

.kv-section {
  margin-bottom: 2rem;
  padding: 1.5rem;
  background: rgba(255,255,255,0.02);
  border-radius: var(--radius-md);
  border: 1px solid var(--border-muted);
  transition: 0.1s;
}

.kv-section-warn {
  border-left: 4px solid #d29922;
  background: rgba(210, 153, 34, 0.05);
}

.kv-section-title {
  color: var(--accent-blue);
  font-size: 1.2rem;
  font-weight: 600;
  margin-bottom: 1rem;
  display: flex;
  align-items: center;
}

.kv-section-title::before {
  content: "▍";
  margin-right: 6px;
  font-size: 1.4rem;
  color: var(--accent-blue);
}

.kv-item {
  margin-bottom: 1.2rem;
}

.kv-item-label {
  color: #e0a800;
  font-weight: 600;
  margin-bottom: 0.2rem;
  font-size: 0.95rem;
}

.kv-item-text {
  line-height: 1.7;
  color: var(--text-secondary);
  padding-left: 0.8rem;
  font-size: 0.95rem;
}

/* =========================================
   10. 辅助/工具类 (保持极简)
   ========================================= */
#action-debug-data {
  background: #1e2a36 !important;
  border-color: #3a4a5a !important;
}

/* 已答/禁用选项 —— 鼠标样式 */
.option-box[style*="background-color"] {
  cursor: default;
}

/* 保证所有按钮内文字不换行 */
button {
  white-space: nowrap;
}

/* 响应式下微小调整 */
@media (max-width: 600px) {
  .top-row-stats {
    flex-direction: column;
    align-items: stretch;
  }
  .top-btn-group {
    justify-content: flex-start;
  }
  #difficulty-bar-root {
    flex-wrap: wrap;
  }
  .btn-common {
    padding: 0.3rem 0.7rem;
    font-size: 0.85rem;
  }
}