/* --- 全局样式变量 (基础色板) --- */
:root {
    --blue-500: #3b82f6; --blue-600: #2563eb;
    --green-500: #22c55e; --green-600: #16a34a;
    --purple-500: #a855f7; --purple-600: #9333ea;
    --gray-500: #6b7280; --gray-600: #4b5563; --gray-700: #374151;
    --yellow-500: #eab308; --yellow-600: #ca8a04;
    --red-500: #ef4444; --red-600: #dc2626;
    --gray-50: #f9fafb; --gray-100: #f3f4f6; --gray-200: #e5e7eb; --gray-300: #d1d5db;
    --white: #ffffff; --black: #000000;
    --light-blue: #7dd3fc; /* 淡蓝色 */
}

/* --- 主题颜色变量定义 (核心改动) --- */
/* 默认主题 (白底黑字) */
:root {
    --color-bg-primary: var(--gray-50);         /* 主背景色 */
    --color-bg-secondary: var(--white);         /* 次级背景/卡片背景 */
    --color-bg-panel: var(--gray-200);          /* 面板背景 (如移动端控制面板) */
    --color-bg-hover: var(--gray-200);          /* 悬停背景色 */
    --color-text-primary: #333;                 /* 主要文字颜色 */
    --color-text-secondary: var(--gray-700);    /* 次要/内容文字颜色 */
    --color-text-muted: var(--gray-500);        /* 提示性/静默文字颜色 */
    --color-text-heading: var(--gray-700);      /* 标题颜色 */
    --color-text-on-accent: var(--white);       /* 在强调色按钮上的文字颜色 */
    --color-border: var(--gray-300);            /* 边框颜色 */
    --color-link: var(--blue-500);              /* 链接颜色 */
    --color-chart: var(--black);                /* E视力表颜色 */
    --color-shadow: rgba(0, 0, 0, 0.1);         /* 阴影颜色 */
}

/* 黑底白字 (暗黑模式) */
.theme-dark {
    --color-bg-primary: #121212;
    --color-bg-secondary: #1e1e1e;
    --color-bg-panel: #2a2a2a;
    --color-bg-hover: #333333;
    --color-text-primary: #e0e0e0;
    --color-text-secondary: #b0b0b0;
    --color-text-muted: var(--gray-500);
    --color-text-heading: #ffffff;
    --color-text-on-accent: var(--white);
    --color-border: #444444;
    --color-link: var(--light-blue);
    --color-chart: var(--white);
    --color-shadow: rgba(255, 255, 255, 0.05);
}

/* 纸质模式 */
.theme-paper {
    --color-bg-primary: #f5f0e8;
    --color-bg-secondary: #faf6f0;
    --color-bg-panel: #e9e2d6;
    --color-bg-hover: #e9e2d6;
    --color-text-primary: #4a443a;
    --color-text-secondary: #5c554a;
    --color-text-muted: #8a8175;
    --color-text-heading: #3c362e;
    --color-text-on-accent: var(--white);
    --color-border: #dcd3c4;
    --color-link: #8c6f4c;
    --color-chart: var(--black);
    --color-shadow: rgba(0, 0, 0, 0.08);
}

/* 护眼模式 */
.theme-eyecare {
    --color-bg-primary: #c7edcc;
    --color-bg-secondary: #e0f2e2;
    --color-bg-panel: #b8dcc0;
    --color-bg-hover: #b8dcc0;
    --color-text-primary: #2e4933;
    --color-text-secondary: #3b5e41;
    --color-text-muted: #5a8a62;
    --color-text-heading: #213525;
    --color-text-on-accent: var(--white);
    --color-border: #a8c9ad;
    --color-link: #1a6a2a;
    --color-chart: var(--black);
    --color-shadow: rgba(0, 0, 0, 0.08);
}


/* --- 基础样式 (Mobile-First) --- */
body, html {
    margin: 0;
    padding: 0;
    height: 100%;
    font-family: -apple-system, BlinkMacSystemFont, "Segoe UI", Roboto, "Helvetica Neue", Arial, "Noto Sans", sans-serif;
    background-color: var(--color-bg-primary);
    color: var(--color-text-primary);
    -webkit-font-smoothing: antialiased;
    touch-action: manipulation;
    -webkit-tap-highlight-color: transparent;
    transition: background-color 0.3s, color 0.3s; /* 添加平滑过渡效果 */
}

/* --- 全局返回按钮样式 (用于内页) --- */
.global-back-button {
    position: fixed;
    top: 1rem;
    right: 1rem;
    z-index: 100;
    padding: 0.5rem 1rem;
    background-color: var(--gray-600);
    color: var(--color-text-on-accent);
    text-decoration: none;
    border-radius: 0.5rem;
    font-size: 0.875rem;
    font-weight: 500;
    box-shadow: 0 2px 4px var(--color-shadow);
}

/* --- 首页右上角 HOME 按钮样式 (新增) --- */
.top-nav {
    position: absolute;
    top: 15px;
    right: 15px;
    z-index: 100;
}

.btn-home-corner {
    display: flex;
    align-items: center;
    justify-content: center;
    gap: 4px;
    background-color: rgba(0, 0, 0, 0.05); /* 这个可以保持不变，或者也用变量 */
    border: 1px solid var(--color-border);
    border-radius: 20px;
    padding: 5px 12px;
    text-decoration: none;
    color: var(--color-text-primary);
    font-size: 14px;
    font-weight: bold;
    transition: all 0.2s;
    cursor: pointer;
}

.btn-home-corner:hover {
    background-color: var(--color-bg-hover);
}

.btn-home-corner svg {
    width: 16px;
    height: 16px;
    fill: currentColor;
}

/* --- 页面容器 --- */
.page {
    display: flex;
    flex-direction: column;
    min-height: 100vh;
    width: 100%;
    box-sizing: border-box;
}

/* --- 主页样式 --- */
#page-home {
    align-items: center;
    justify-content: center;
    padding: 1rem;
}
#page-home h1 {
    font-size: 2rem;
    font-weight: bold;
    color: var(--color-text-heading);
    margin-bottom: 2rem;
    text-align: center;
}
.home-grid {
    display: grid;
    grid-template-columns: 1fr;
    gap: 1rem;
    width: 100%;
    max-width: 48rem;
}

/* --- 按钮通用样式 --- */
.btn, .footer-btn, .mobile-control-btn {
    color: var(--color-text-on-accent);
    border-radius: 0.5rem;
    box-shadow: 0 4px 6px -1px var(--color-shadow);
    border: none;
    cursor: pointer;
    transition: all 0.1s ease;
    display: flex;
    align-items: center;
    justify-content: center;
    font-weight: 600;
    text-decoration: none;
    box-sizing: border-box;
}
.btn:active, .footer-btn:active, .mobile-control-btn:active {
    transform: scale(0.97);
    filter: brightness(0.95);
}

/* --- 按钮颜色工具类 --- */
.bg-blue { background-color: var(--blue-500); }
.bg-green { background-color: var(--green-500); }
.bg-purple { background-color: var(--purple-500); }
.bg-gray { background-color: var(--gray-500); }
.bg-red { background-color: var(--red-500); }
.bg-yellow { background-color: var(--yellow-500); }
.bg-light-blue { background-color: var(--light-blue); }


/* --- 主页按钮特定样式 --- */
.btn { padding: 1.25rem; font-size: 1.125rem; width: 100%; }
.btn svg { margin-right: 0.5rem; width: 20px; height: 20px; }

/* --- 内容页 & Prose 样式 --- */
.content-page { padding: 1rem; max-width: 56rem; margin: 0 auto; }
.content-page h2 { font-size: 1.5rem; font-weight: bold; text-align: center; margin-bottom: 0.5rem; color: var(--color-text-heading); }
.content-page h4 { font-size: 1.1rem; font-weight: bold; margin-top: 1.5rem; margin-bottom: 0.5rem; color: var(--color-text-heading); }
.back-btn-container { text-align: center; margin-top: 1.5rem; }
.back-btn { padding: 0.75rem 1.25rem; background-color: var(--gray-600); color: var(--color-text-on-accent); border: none; border-radius: 0.5rem; cursor: pointer; }
.prose { background-color: var(--color-bg-secondary); padding: 1.25rem; border-radius: 0.5rem; box-shadow: 0 1px 3px 0 var(--color-shadow); line-height: 1.6; font-size: 0.95rem; }
.prose p, .prose li { color: var(--color-text-secondary); }
.prose ol, .prose ul { padding-left: 1.25rem; margin-bottom: 1rem; }
.prose .disclaimer { font-weight: bold; color: var(--red-600); margin-top: 1rem; }
.author-info { text-align: center; color: var(--color-text-muted); font-size: 0.9rem; margin-bottom: 1.5rem; }
.author-info a { color: var(--color-link); text-decoration: none; }

/* --- 视标选择页样式 --- */
.setup-page { padding: 1rem; }
.setup-page h2 { font-size: 1.5rem; font-weight: bold; text-align: center; margin-bottom: 1rem; color: var(--color-text-heading); }
.level-grid { display: grid; grid-template-columns: repeat(3, 1fr); gap: 0.75rem; max-width: 64rem; margin: 0 auto; }
.level-btn { padding: 0.75rem; background-color: var(--color-bg-secondary); border: 2px solid var(--color-border); border-radius: 0.5rem; cursor: pointer; }
.level-btn .decimal { display: block; font-size: 1rem; font-weight: bold; color: var(--color-text-secondary); }
.level-btn .logmar { display: block; font-size: 0.8rem; color: var(--color-text-muted); }

/* --- 测试页样式 --- */
#page-test { background-color: var(--color-bg-primary); } /* 使用主背景色 */
.test-header {
    padding: 0.75rem;
    background-color: var(--color-bg-secondary);
    box-shadow: 0 2px 4px var(--color-shadow);
    display: flex;
    flex-direction: column;
    align-items: center;
    justify-content: center;
    gap: 0.5rem;
    flex-shrink: 0;
}
.test-title { font-size: 1rem; font-weight: bold; text-align: center; color: var(--color-text-heading); }
.test-info { display: flex; gap: 0.75rem; font-size: 0.875rem; color: var(--color-text-muted); }
.test-main { flex-grow: 1; display: flex; align-items: center; justify-content: center; position: relative; overflow: hidden; }
#e-chart-container { display: flex; align-items: center; justify-content: center; }
#e-chart-svg { color: var(--color-chart); } /* 关键：视力表颜色也使用变量 */

/* --- 移动端专属控制面板 --- */
.mobile-controls-panel {
    display: flex;
    flex-direction: column;
    gap: 1rem;
    padding: 1rem;
    background-color: var(--color-bg-panel);
    flex-shrink: 0;
    align-items: center;
}

.directional-pad-container {
    display: grid;
    grid-template-columns: repeat(3, 1fr);
    grid-template-rows: repeat(3, 1fr);
    gap: 0.25rem;
    width: 180px;
    height: 180px;
}
.directional-pad-container .mobile-control-btn {
    background-color: var(--color-bg-secondary);
    color: var(--color-text-secondary);
    height: 100%;
    width: 100%;
    font-size: 0.75rem;
    flex-direction: column;
}
.directional-pad-container .mobile-control-btn svg { width: 28px; height: 28px; }
.directional-pad-container .btn-dir-up    { grid-area: 1 / 2 / 2 / 3; }
.directional-pad-container .btn-dir-left  { grid-area: 2 / 1 / 3 / 2; }
.directional-pad-container .btn-dir-right { grid-area: 2 / 3 / 3 / 4; }
.directional-pad-container .btn-dir-down  { grid-area: 3 / 2 / 4 / 3; }

/* 底部菜单按钮 */
.menu-btn-container {
    width: 100%;
    display: flex;
    justify-content: center;
}
.menu-btn-container .mobile-control-btn {
    height: auto;
    padding: 0.75rem 2rem;
    font-size: 1rem;
    width: auto;
    min-width: 160px;
    border-radius: 2rem;
}

/* --- 桌面端专属底部 --- */
.desktop-footer {
    display: none;
    justify-content: center;
    padding: 1rem;
    background-color: var(--color-bg-secondary);
    flex-shrink: 0;
}
.desktop-footer .footer-btn { 
    font-size: 1rem; 
    padding: 0.75rem 2.5rem; 
    font-weight: 500;
    width: auto;
    border-radius: 2rem;
}

/* --- 结果/菜单弹窗样式 --- */
#result-modal { position: fixed; inset: 0; background-color: rgba(0,0,0,0.7); display: flex; align-items: center; justify-content: center; z-index: 50; padding: 1rem; }
.modal-content { 
    background-color: var(--color-bg-secondary); 
    border-radius: 0.75rem; 
    box-shadow: 0 25px 50px -12px rgba(0,0,0,0.25); 
    padding: 1.5rem; 
    max-width: 20rem;
    width: 100%; 
    text-align: center; 
}
.modal-content h2 { font-size: 1.5rem; font-weight: bold; margin-bottom: 0.75rem; color: var(--color-text-heading); }
.modal-content p { font-size: 1rem; margin-bottom: 0.4rem; color: var(--color-text-secondary); }
.modal-actions { display: flex; flex-direction: column; gap: 0.75rem; margin-top: 1.5rem; }
.modal-actions .btn { padding: 0.75rem 1rem; font-size: 0.95rem; }
.modal-actions button:focus {
    outline: 5px solid #ffdd00;
    transform: scale(1.1);
    z-index: 10;
    box-shadow: 0 0 15px rgba(0,0,0,0.5);
}

/* 评价文字颜色 (这些是状态色，通常不需要随主题改变) */
.eval-text { font-size: 1.1rem; margin-top: 10px; font-weight: bold; }
.text-green { color: var(--green-600); }
.text-red { color: var(--red-600); }
.text-yellow { color: var(--yellow-600); }

/* --- 历史记录页样式 --- */
.history-table-container { overflow-x: auto; background-color: var(--color-bg-secondary); border-radius: 0.5rem; margin-top: 1.5rem; }
.history-table { width: 100%; text-align: left; color: var(--color-text-muted); font-size: 0.8rem; border-collapse: collapse; }
.history-table thead { background-color: var(--color-bg-panel); color: var(--color-text-secondary); }
.history-table th, .history-table td { padding: 0.6rem 0.4rem; border-bottom: 1px solid var(--color-border); }
.history-actions { display: flex; justify-content: center; gap: 0.75rem; margin-top: 1.5rem; }

/* --- 桌面端适配 --- */
@media (min-width: 769px) {
    #page-home h1 { font-size: 3rem; margin-bottom: 3rem; }
    .home-grid { grid-template-columns: 1fr 1fr; gap: 1.5rem; }
    .content-page { padding: 2rem; }
    .level-grid { grid-template-columns: repeat(7, 1fr); }
    
    .test-header { flex-direction: row; justify-content: space-between; padding: 1rem; }
    .mobile-controls-panel { display: none; }
    .desktop-footer { display: flex; }
    
    .modal-actions { flex-direction: row; justify-content: center; }
    .modal-actions .btn { width: auto; min-width: 100px; }
}

/*
--- 如何使用 ---
您现在可以通过 JavaScript 来切换主题。
例如，您可以在页面上创建几个按钮，点击它们时执行相应的函数。

示例 HTML:
<div class="theme-switcher">
  <button onclick="setTheme('light')">默认</button>
  <button onclick="setTheme('dark')">暗黑</button>
  <button onclick="setTheme('paper')">纸质</button>
  <button onclick="setTheme('eyecare')">护眼</button>
</div>

示例 JavaScript:
function setTheme(themeName) {
  // 移除所有可能的主题类
  document.body.classList.remove('theme-dark', 'theme-paper', 'theme-eyecare');
  
  // 如果不是默认的 'light' 主题，则添加相应的主题类
  if (themeName !== 'light') {
    document.body.classList.add('theme-' + themeName);
  }
  
  // (可选) 将用户选择的主题保存到 localStorage，以便下次访问时自动应用
  // localStorage.setItem('theme', themeName);
}

// (可选) 页面加载时，检查 localStorage 中是否有保存的主题
// document.addEventListener('DOMContentLoaded', () => {
//   const savedTheme = localStorage.getItem('theme') || 'light';
//   setTheme(savedTheme);
// });
*/

/* --- 主题切换器样式 --- */
#theme-switcher {
    position: fixed;
    bottom: 20px;
    left: 20px;
    z-index: 1000;
}

#theme-toggle-btn {
    width: 56px;
    height: 56px;
    border-radius: 50%;
    background-color: var(--color-bg-secondary);
    color: var(--color-text-primary);
    border: 1px solid var(--color-border);
    box-shadow: 0 4px 12px rgba(0,0,0,0.15);
    cursor: pointer;
    display: flex;
    align-items: center;
    justify-content: center;
    padding: 0;
    transition: all 0.2s ease-in-out;
}

#theme-toggle-btn:hover {
    transform: scale(1.1);
    box-shadow: 0 6px 16px rgba(0,0,0,0.2);
}

#theme-toggle-btn svg {
    width: 28px;
    height: 28px;
}

#theme-menu {
    position: absolute;
    bottom: 70px; /* 在按钮上方 */
    left: 0;
    width: 180px;
    background-color: var(--color-bg-secondary);
    border-radius: 8px;
    box-shadow: 0 8px 24px rgba(0,0,0,0.2);
    border: 1px solid var(--color-border);
    overflow: hidden;
    display: flex;
    flex-direction: column;
    opacity: 1;
    transform: translateY(0);
    transition: opacity 0.2s ease, transform 0.2s ease;
}

#theme-menu.hidden {
    opacity: 0;
    transform: translateY(10px);
    pointer-events: none; /* 隐藏时不可点击 */
}

#theme-menu button {
    display: flex;
    align-items: center;
    gap: 12px;
    width: 100%;
    padding: 12px 16px;
    background: none;
    border: none;
    border-bottom: 1px solid var(--color-border);
    color: var(--color-text-secondary);
    text-align: left;
    font-size: 14px;
    cursor: pointer;
    transition: background-color 0.2s;
}

#theme-menu button:last-child {
    border-bottom: none;
}

#theme-menu button:hover {
    background-color: var(--color-bg-hover);
}

#theme-menu button.active {
    color: var(--color-link); /* 使用链接颜色表示选中 */
    font-weight: bold;
}

#theme-menu button svg {
    width: 20px;
    height: 20px;
    flex-shrink: 0;
}