:root {
    --bg-color: #1a1a1a;
    --card-bg: #2d2d2d;
    --text-primary: #ffffff;
    --text-secondary: #a0a0a0;
    --border-color: #444444;
    --accent-color: #4a9eff;
    --accent-rgb: 74, 158, 255;
    --hover-bg: #3d3d3d;
    --element-gap: 16px;
}

body.light {
    --bg-color: #f5f5f5;
    --card-bg: #ffffff;
    --text-primary: #333333;
    --text-secondary: #666666;
    --border-color: #e0e0e0;
    --accent-color: #0066cc;
    --accent-rgb: 0, 102, 204;
    --hover-bg: #f0f0f0;
}

* {
    margin: 0;
    padding: 0;
    box-sizing: border-box;
}

body {
    background-color: var(--bg-color);
    color: var(--text-primary);
    font-family: -apple-system, BlinkMacSystemFont, "Segoe UI", Roboto, Oxygen, Ubuntu, Cantarell, sans-serif;
    min-height: 100vh;
    transition: background-color 0.3s ease, color 0.3s ease;
    padding: 20px;
    overflow-x: hidden;
}

/* 主题切换按钮 - 右上角悬浮显示 */
.theme-toggle-area {
    position: fixed;
    top: 0;
    right: 0;
    width: 80px;
    height: 80px;
    z-index: 100;
}

.theme-toggle {
    position: absolute;
    top: 20px;
    right: 20px;
    width: 36px;
    height: 36px;
    border-radius: 50%;
    background: var(--card-bg);
    border: 1px solid var(--border-color);
    display: flex;
    align-items: center;
    justify-content: center;
    cursor: pointer;
    transition: all 0.3s ease;
    font-size: 16px;
    opacity: 0;
}

.theme-toggle-area:hover .theme-toggle {
    opacity: 1;
}

.theme-toggle:hover {
    background: var(--hover-bg);
    transform: scale(1.05);
}

/* 主容器 - 绝对定位，JS控制垂直位置 */
.main-container {
    position: absolute;
    left: 50%;
    transform: translateX(-50%);
    width: calc(100% - 40px);
    max-width: 600px;
    display: flex;
    flex-direction: column;
    align-items: center;
}

.start-title {
    font-size: 48px;
    font-weight: 300;
    margin-bottom: var(--element-gap);
    color: var(--text-primary);
    letter-spacing: 2px;
}

.time-display {
    margin-bottom: var(--element-gap);
    font-size: 14px;
    color: var(--text-secondary);
    text-align: center;
    white-space: nowrap;
    overflow-x: auto;
    max-width: 100%;
    display: none;
    padding: 4px 8px;
    border-radius: 4px;
    background: rgba(var(--accent-rgb), 0.05);
}

.time-display.visible {
    display: block;
}

.search-container {
    width: 100%;
    display: flex;
    align-items: center;
    background: var(--card-bg);
    border: 1px solid var(--border-color);
    border-radius: 24px;
    padding: 4px;
    transition: border-color 0.3s ease, box-shadow 0.3s ease;
    position: relative;
}

.search-container:focus-within {
    border-color: var(--accent-color);
    box-shadow: 0 0 0 3px rgba(var(--accent-rgb), 0.1);
}

/* 引擎切换按钮 - 单字符圆形，多字符自动伸缩为椭圆形 */
.engine-toggle {
    min-width: 36px;
    height: 36px;
    border-radius: 18px;
    border: none;
    background: var(--accent-color);
    color: white;
    cursor: pointer;
    display: flex;
    align-items: center;
    justify-content: center;
    font-size: 14px;
    font-weight: bold;
    transition: all 0.3s ease;
    flex-shrink: 0;
    position: relative;
    padding: 0 6px;
    white-space: nowrap;
}

.engine-toggle:hover {
    transform: scale(1.05);
    opacity: 0.9;
}

/* 搜索引擎下拉列表 */
.engine-dropdown {
    position: absolute;
    top: calc(100% + 8px);
    left: 0;
    background: var(--card-bg);
    border: 1px solid var(--border-color);
    border-radius: 12px;
    padding: 6px 0;
    min-width: 180px;
    box-shadow: 0 8px 24px rgba(0, 0, 0, 0.3);
    z-index: 200;
    display: none;
    animation: fadeIn 0.15s ease;
}

.engine-dropdown.show {
    display: block;
}

@keyframes fadeIn {
    from { opacity: 0; transform: translateY(-4px); }
    to { opacity: 1; transform: translateY(0); }
}

.engine-dropdown-item {
    display: flex;
    align-items: center;
    padding: 10px 16px;
    cursor: pointer;
    transition: background 0.2s ease;
    gap: 10px;
    color: var(--text-primary);
    font-size: 14px;
}

.engine-dropdown-item:hover {
    background: var(--hover-bg);
}

.engine-dropdown-item.active {
    color: var(--accent-color);
    font-weight: 600;
}

.engine-dropdown-icon {
    width: 24px;
    height: 24px;
    border-radius: 50%;
    background: var(--accent-color);
    color: white;
    display: flex;
    align-items: center;
    justify-content: center;
    font-size: 11px;
    font-weight: bold;
    flex-shrink: 0;
}

.engine-dropdown-item.active .engine-dropdown-icon {
    background: var(--accent-color);
    box-shadow: 0 0 0 2px rgba(var(--accent-rgb), 0.3);
}

.search-input {
    flex: 1;
    border: none;
    background: transparent;
    padding: 8px 16px;
    font-size: 16px;
    color: var(--text-primary);
    outline: none;
}

.search-input::placeholder {
    color: var(--text-secondary);
}

/* 时间显示开关 - 右下角悬浮显示 */
.time-toggle-area {
    position: fixed;
    right: 0;
    bottom: 0;
    width: 80px;
    height: 80px;
    z-index: 100;
}

.time-toggle-btn {
    position: absolute;
    right: 20px;
    bottom: 20px;
    width: 36px;
    height: 36px;
    border-radius: 50%;
    border: 2px solid var(--text-secondary);
    background: transparent;
    cursor: pointer;
    transition: all 0.3s ease;
    opacity: 0;
    display: flex;
    align-items: center;
    justify-content: center;
    font-size: 14px;
}

.time-toggle-area:hover .time-toggle-btn {
    opacity: 1;
}

.time-toggle-btn.active {
    border-color: var(--accent-color);
    background: rgba(var(--accent-rgb), 0.1);
    color: var(--accent-color);
}

@media (max-width: 600px) {
    .start-title {
        font-size: 36px;
    }

    .time-display {
        font-size: 12px;
    }

    .search-input {
        font-size: 14px;
    }

    .theme-toggle,
    .time-toggle-btn {
        width: 32px;
        height: 32px;
        font-size: 14px;
    }

    .engine-dropdown {
        min-width: 160px;
    }
}