src/App.css

/* =========================================
   1. REACT layout setting
   ========================================= */
html, body, #root {
    width: 100%;
    height: 100%;
    margin: 0;
    padding: 0;
}

.app-container {
    width: 100%;
    min-height: 100vh; /* screen height */
    display: flex;
    flex-direction: column;
    background-color: #f9f9f9;
}

/* =========================================
   2. original layout
   ========================================= */

/* GLOBAL STYLES */
body {
    font-family: 'Nunito', sans-serif;
    background-color: #f9f9f9;
    overflow-x: hidden;
    overflow-y: auto;
}

/* dynamic class name */
.hidden {
    display: none !important;
}

/* TOP MENU */
#top-menu {
    height: 60px;
    background-color: white;
    display: flex;
    align-items: center;
    justify-content: center; /* Center buttons horizontally */
    box-shadow: 0 2px 5px rgba(0,0,0,0.05);
    position: fixed;
    top: 0;
    width: 100%;
    z-index: 1000;
}

.menu-btn {
    background: none;
    border: none;
    font-family: 'Nunito', sans-serif;
    font-size: 16px;
    color: #333;
    padding: 10px 20px;
    cursor: pointer;
    transition: background-color 0.2s;
}

.menu-btn:hover {
    background-color: #f0f0f0;
    border-radius: 4px;
}

/* active for React */
.menu-btn.active {
    font-weight: bold;
    color: #007BFF;
    background-color: #eef7ff;
    border-radius: 4px;
}

.separator {
    width: 1px;
    height: 20px;
    background-color: #555; /* Dark gray separator */
    margin: 0 5px;
}

/* PAGE CONTAINER */
.page {
    /* content under menu */
    min-height: calc(100vh - 60px);
    width: 100%;
    padding-top: 60px; /* Space for fixed menu */
    padding-bottom: 40px; /* Space at bottom for scrolling */
    box-sizing: border-box;
    display: flex;
    flex-direction: column;
    align-items: center;
    overflow-y: auto; 
}

/* Ensure page titles are black */
.page h1 {
    color: #000 !important;
    background: transparent !important;
}

.page-title {
    color: #000 !important;
    background: transparent !important;
}

/* PAGE A SPECIFIC */
#page-a {
    justify-content: center; /* Center vertically */
    /* 注意：因为 React 结构变化，如果感觉偏下，可以微调这个 margin-top */
    margin-top: -40px; 
    flex: 1; /* 确保它占满剩余空间以便垂直居中 */
}

#page-a h1 {
    font-size: 80px;
    margin: 0 0 10px 0;
    color: #000;
    text-align: center; /* 确保文字居中 */
}

#page-a p {
    color: #666;
    font-size: 20px;
    margin-bottom: 40px;
    text-align: center;
}

.btn-main {
    background-color: #007BFF; /* Blue */
    color: white;
    border: none;
    padding: 15px 50px;
    font-size: 20px;
    font-family: 'Nunito', sans-serif;
    border-radius: 30px; /* Fully rounded corners */
    cursor: pointer;
    transition: transform 0.2s ease;
}

.btn-main:hover {
    transform: scale(1.1); /* Zoom effect */
}

/* PAGE B SPECIFIC */
#page-b {
    justify-content: space-evenly; /* Distribute vertical space */
    padding-bottom: 20px;
    min-height: calc(100vh - 60px); /* 再次确保高度足够 */
}

/* 1. Display Area */
#display-area {
    width: 60%;
    height: 50vh; /* 改用 vh 单位，确保在不同屏幕下的高度比例 */
    min-height: 300px;
    border: 2px solid #ddd;
    border-radius: 12px;
    background-color: #fff;
    display: flex;
    align-items: center;
    justify-content: center;
    color: #555;
    font-size: 24px;
    position: relative;
    /* 确保视频元素也能居中且不溢出 */
    overflow: hidden; 
}

#display-area video {
    width: 100%;
    height: 100%;
    object-fit: cover; /* 类似于 background-size: cover */
}

/* 2. Timeline Area */
#timeline-area {
    width: 60%;
    height: 80px;
    position: relative;
    display: flex;
    flex-direction: column;
    justify-content: flex-end;
}

.timeline-label {
    position: absolute;
    top: 0;
    left: 0;
    color: #888;
    font-size: 14px;
}

#timeline-line {
    width: 100%;
    height: 2px;
    background-color: #87CEEB; /* Light blue */
}

/* 3. Control Panel */
#control-panel {
    display: flex;
    gap: 20px;
    width: 60%;
    justify-content: space-between;
}

.action-btn {
    flex: 1; /* Evenly distributed width */
    padding: 12px 0;
    border: none;
    border-radius: 12px;
    font-size: 16px;
    font-family: 'Nunito', sans-serif;
    font-weight: 700;
    cursor: pointer;
    color: white;
    transition: opacity 0.2s;
}

.action-btn:hover {
    opacity: 0.9;
}

.action-btn.green { background-color: #28a745; }
.action-btn.yellow { background-color: #ffce0b; }
.action-btn.blue { background-color: #326ed6; }
.action-btn.red { background-color: #dc3545; }

/* 4. Frame Control */
#frame-control {
    display: flex;
    align-items: center;
    gap: 15px;
    color: #333;
    font-weight: bold;
}

#frame-slider {
    width: 200px;
    cursor: pointer;
}

#frame-input {
    width: 50px;
    padding: 5px;
    border: 1px solid #ccc;
    border-radius: 5px;
    text-align: center;
    font-family: 'Nunito', sans-serif;
}

/* ================ ACHIEVEMENT PAGE ================ */

.stats-grid {
    display: grid;
    grid-template-columns: repeat(4, 1fr);
    gap: 20px;
    width: 80%;
    margin: 40px auto;
}

.stat-card {
    background: white;
    padding: 30px;
    border-radius: 12px;
    text-align: center;
    box-shadow: 0 2px 10px rgba(0,0,0,0.1);
}

.stat-number {
    font-size: 48px;
    font-weight: bold;
    color: #007BFF;
    margin-bottom: 10px;
}

.stat-label {
    font-size: 16px;
    color: #666;
}

.achievements-section {
    width: 80%;
    margin: 0 auto;
}

.achievements-section h2 {
    color: #333;
    margin-bottom: 20px;
}

.badges-grid {
    display: grid;
    grid-template-columns: repeat(3, 1fr);
    gap: 20px;
}

.badge {
    background: white;
    padding: 30px 20px;
    border-radius: 12px;
    text-align: center;
    box-shadow: 0 2px 10px rgba(0,0,0,0.1);
    transition: transform 0.2s;
}

.badge:hover {
    transform: translateY(-5px);
}

.badge.locked {
    opacity: 0.4;
    filter: grayscale(100%);
}

.badge-icon {
    font-size: 64px;
    margin-bottom: 15px;
}

.badge-name {
    font-size: 16px;
    font-weight: bold;
    color: #333;
}

/* ================ RECORDS PAGE ================ */

.records-controls {
    display: flex;
    gap: 10px;
    margin: 20px auto;
    width: 80%;
    justify-content: center;
}

.filter-btn {
    padding: 10px 20px;
    border: 2px solid #007BFF;
    background: white;
    color: #007BFF;
    border-radius: 8px;
    cursor: pointer;
    font-family: 'Nunito', sans-serif;
    font-weight: 600;
    transition: all 0.2s;
}

.filter-btn:hover {
    background: #e7f3ff;
}

.filter-btn.active {
    background: #007BFF;
    color: white;
}

.chart-container {
    width: 80%;
    background: white;
    padding: 30px;
    border-radius: 12px;
    margin: 20px auto;
    box-shadow: 0 2px 10px rgba(0,0,0,0.1);
}

#focus-chart {
    display: block;
    margin: 0 auto;
    /* 确保图表在容器内自适应 */
    max-width: 100%;
}

.sessions-list {
    width: 80%;
    margin: 20px auto;
}

.sessions-list h2 {
    color: #333;
    margin-bottom: 15px;
}

#sessions-table {
    width: 100%;
    background: white;
    border-collapse: collapse;
    border-radius: 12px;
    overflow: hidden;
    box-shadow: 0 2px 10px rgba(0,0,0,0.1);
}

#sessions-table th {
    background: #007BFF;
    color: white;
    padding: 15px;
    text-align: left;
    font-weight: 600;
}

#sessions-table td {
    padding: 12px 15px;
    border-bottom: 1px solid #eee;
}

#sessions-table tr:last-child td {
    border-bottom: none;
}

#sessions-table tbody tr:hover {
    background: #f8f9fa;
}

.btn-view {
    padding: 6px 12px;
    background: #007BFF;
    color: white;
    border: none;
    border-radius: 5px;
    cursor: pointer;
    font-family: 'Nunito', sans-serif;
    transition: background 0.2s;
}

.btn-view:hover {
    background: #0056b3;
}

/* ================ SETTINGS PAGE ================ */

.settings-container {
    width: 60%;
    max-width: 800px;
    margin: 20px auto;
}

.setting-group {
    background: white;
    padding: 30px;
    border-radius: 12px;
    margin-bottom: 20px;
    box-shadow: 0 2px 10px rgba(0,0,0,0.1);
}

.setting-group h2 {
    margin-top: 0;
    color: #333;
    font-size: 20px;
    margin-bottom: 20px;
    border-bottom: 2px solid #007BFF;
    padding-bottom: 10px;
}

.setting-item {
    margin-bottom: 25px;
}

.setting-item:last-child {
    margin-bottom: 0;
}

.setting-item label {
    display: block;
    margin-bottom: 8px;
    color: #333;
    font-weight: 600;
}

.slider-group {
    display: flex;
    align-items: center;
    gap: 15px;
}

.slider-group input[type="range"] {
    flex: 1;
}

.slider-group span {
    min-width: 40px;
    text-align: center;
    font-weight: bold;
    color: #007BFF;
    font-size: 18px;
}

.setting-description {
    font-size: 14px;
    color: #666;
    margin-top: 5px;
    font-style: italic;
}

input[type="checkbox"] {
    margin-right: 10px;
    cursor: pointer;
}

input[type="number"] {
    width: 100px;
    padding: 8px;
    border: 1px solid #ccc;
    border-radius: 5px;
    font-family: 'Nunito', sans-serif;
}

/* --- 新的代码：让按钮居中且变宽 --- */
.setting-group .action-btn {
    display: inline-block;   /* 允许并排显示 */
    width: 48%;              /* 两个按钮各占约一半宽度 (留2%缝隙) */
    margin: 15px 1%;         /* 上下 15px，左右 1% 间距来实现居中和分隔 */
    text-align: center;      /* 文字居中 */
    box-sizing: border-box;  /* 确保边框不会撑大按钮导致换行 */
}

#save-settings {
    display: block;
    margin: 20px auto;
}

/* ================ HELP PAGE ================ */

.help-container {
    width: 70%;
    max-width: 900px;
    margin: 20px auto;
}

/* Fake ad block (Help page) */
.fake-ad {
    position: relative;
    display: block;
    width: min(600px, 90%);
    margin: 10px auto 30px auto;
    border: 1px solid #e5e5e5;
    border-radius: 12px;
    overflow: hidden;
    background: #fff;
    text-decoration: none;
    box-shadow: 0 8px 24px rgba(0,0,0,0.12);
    transition: transform 0.2s ease, box-shadow 0.2s ease;
}

.fake-ad:hover {
    transform: translateY(-2px);
    box-shadow: 0 12px 30px rgba(0,0,0,0.16);
}

.fake-ad img {
    display: block;
    width: 100%;
    height: auto;
}

.fake-ad-badge {
    position: absolute;
    top: 12px;
    left: 12px;
    background: rgba(0,0,0,0.75);
    color: #fff;
    font-size: 12px;
    padding: 4px 8px;
    border-radius: 6px;
    letter-spacing: 0.5px;
}

.fake-ad-cta {
    position: absolute;
    right: 12px;
    bottom: 12px;
    background: #111;
    color: #fff;
    font-size: 14px;
    padding: 8px 12px;
    border-radius: 8px;
}

.help-section {
    background: white;
    padding: 30px;
    border-radius: 12px;
    margin-bottom: 20px;
    box-shadow: 0 2px 10px rgba(0,0,0,0.1);
}

.help-section h2 {
    color: #007BFF;
    margin-top: 0;
    margin-bottom: 15px;
}

.help-section ol,
.help-section ul {
    line-height: 1.8;
    color: #333;
}

.help-section p {
    line-height: 1.6;
    color: #333;
}

details {
    margin: 15px 0;
    cursor: pointer;
    padding: 10px;
    background: #f8f9fa;
    border-radius: 5px;
}

summary {
    font-weight: bold;
    padding: 5px;
    color: #007BFF;
}

details[open] summary {
    margin-bottom: 10px;
    border-bottom: 1px solid #ddd;
    padding-bottom: 10px;
}

details p {
    margin: 10px 0 0 0;
}

/* ================ SESSION SUMMARY MODAL ================ */
/* 如果将来要做弹窗，这些样式可以直接复用 */
.modal-overlay {
    position: fixed;
    top: 0;
    left: 0;
    width: 100%;
    height: 100%;
    background: rgba(0, 0, 0, 0.7);
    display: flex;
    align-items: center;
    justify-content: center;
    z-index: 2000;
}

.modal-content {
    background: white;
    padding: 40px;
    border-radius: 16px;
    box-shadow: 0 10px 40px rgba(0,0,0,0.3);
    max-width: 500px;
    width: 90%;
}

.modal-content h2 {
    margin-top: 0;
    color: #333;
    text-align: center;
    margin-bottom: 30px;
}

.summary-stats {
    margin-bottom: 30px;
}

.summary-item {
    display: flex;
    justify-content: space-between;
    padding: 15px 0;
    border-bottom: 1px solid #eee;
}

.summary-item:last-child {
    border-bottom: none;
}

.summary-label {
    font-weight: 600;
    color: #666;
}

.summary-value {
    font-weight: bold;
    color: #007BFF;
    font-size: 18px;
}

.modal-content .btn-main {
    display: block;
    margin: 0 auto;
    padding: 12px 40px;
}

/* ================ TIMELINE BLOCKS ================ */

.timeline-block {
    transition: opacity 0.2s;
    border-radius: 2px;
}

.timeline-block:hover {
    opacity: 0.7;
}

/* ================ RESPONSIVE DESIGN ================ */

@media (max-width: 1200px) {
    .stats-grid {
        grid-template-columns: repeat(2, 1fr);
    }

    .badges-grid {
        grid-template-columns: repeat(2, 1fr);
    }
}

@media (max-width: 768px) {
    .stats-grid,
    .badges-grid {
        grid-template-columns: 1fr;
        width: 90%;
    }

    .settings-container,
    .help-container,
    .chart-container,
    .sessions-list,
    .records-controls {
        width: 90%;
    }

    #control-panel {
        width: 90%;
        flex-wrap: wrap;
    }

    #display-area {
        width: 90%;
    }

    #timeline-area {
        width: 90%;
    }

    #frame-control {
        width: 90%;
        flex-direction: column;
    }
}
/* =========================================
   SESSION RESULT OVERLAY (新增)
   ========================================= */

.session-result-overlay {
    position: absolute;
    top: 0;
    left: 0;
    width: 100%;
    height: 100%;
    background-color: rgba(0, 0, 0, 0.85); /* 深色半透明背景 */
    display: flex;
    flex-direction: column;
    justify-content: center;
    align-items: center;
    color: white;
    z-index: 10;
    animation: fadeIn 0.5s ease;
    backdrop-filter: blur(5px); /* 背景模糊效果 (可选) */
}

.session-result-overlay h3 {
    font-size: 32px;
    margin-bottom: 30px;
    color: #4cd137; /* 绿色标题 */
    text-transform: uppercase;
    letter-spacing: 2px;
}

.session-result-overlay .result-item {
    display: flex;
    justify-content: space-between;
    width: 200px; /* 控制宽度 */
    margin-bottom: 15px;
    font-size: 20px;
    border-bottom: 1px solid rgba(255,255,255,0.2);
    padding-bottom: 5px;
}

.session-result-overlay .label {
    color: #ccc;
    font-weight: normal;
}

.session-result-overlay .value {
    color: #fff;
    font-weight: bold;
    font-family: 'Courier New', monospace; /* 看起来像数据 */
}

@keyframes fadeIn {
    from { opacity: 0; transform: scale(0.95); }
    to { opacity: 1; transform: scale(1); }
}

/* ================= 迎宾弹窗样式 ================= */
.welcome-modal-overlay {
position: fixed;
top: 0; left: 0; right: 0; bottom: 0;
background-color: rgba(0, 0, 0, 0.7);
display: flex;
justify-content: center;
align-items: center;
z-index: 9999;
}

.welcome-modal {
background-color: #1e1e24;
padding: 40px;
border-radius: 15px;
text-align: center;
box-shadow: 0 10px 30px rgba(0,0,0,0.5);
border: 1px solid #333;
}

.welcome-modal h2 { margin-top: 0; color: #fff; }
.welcome-modal p { margin-bottom: 30px; color: #ccc; }
.welcome-buttons { display: flex; gap: 20px; justify-content: center; }

/* ================= 左上角头像样式 (修改版) ================= */
#top-menu {
position: relative;
display: flex;
justify-content: center;
align-items: center;
}

.avatar-container {
position: absolute;
left: 20px;
cursor: pointer;
}

.avatar-circle {
width: 40px;
height: 40px;
border-radius: 50%;
display: flex;
justify-content: center;
align-items: center;
font-weight: bold;
font-size: 1.2rem;
color: white;
transition: all 0.3s ease;
border: 2px solid transparent;
}

.avatar-circle.user { background-color: #555; }
.avatar-circle.admin { background-color: #ffaa00; border-color: #fff; box-shadow: 0 0 10px rgba(255, 170, 0, 0.5); }
/* ================= 首页按钮 2x2 响应式网格 (终极修正版) ================= */
.home-button-grid {
  display: grid;
  grid-template-columns: 1fr 1fr; /* 强行平分两列，绝不妥协 */
  gap: 20px; /* 按钮之间的间距 */
  width: 100%;
  max-width: 500px; /* 限制最大宽度，宽屏下也不会显得傻大黑粗 */
  margin: 40px auto 0 auto; /* 上边距40px，左右auto保证绝对居中！ */
}

.home-button-grid .btn-main {
  width: 100%;
  height: 60px; /* 统一高度，像一块块整齐的砖头 */
  margin: 0; /* 清除默认外边距 */
  padding: 10px;
  font-size: 1rem;
  display: flex;
  justify-content: center;
  align-items: center;
  text-align: center;
  box-sizing: border-box; /* 保证边框和内边距不会撑破格子 */
}

/* 📱 手机端专属适配 (屏幕宽度小于 600px 时自动缩放) */
@media (max-width: 600px) {
  .home-button-grid {
    gap: 15px; 
    max-width: 90%; 
  }
  
  .home-button-grid .btn-main {
    height: 50px;
    font-size: 0.85rem; 
  }
}