/* style.css - 核心样式库 */

/* ==============================
   1. 全局变量与基础设置
   ============================== */
:root {
    /* 核心色板 */
    --bg-body: #0f1115;       /* 极深背景 */
    --bg-surface: #1a1d24;    /* 卡片浮层 */
    --bg-surface-hover: #222630;
    
    --primary: #3b82f6;       /* 品牌蓝 */
    --primary-hover: #2563eb;
    --secondary: #64748b;     /* 辅助灰 */
    --accent: #f59e0b;        /* 强调橙 (价格/提示) */
    --success: #10b981;       /* 成功绿 */
    --danger: #ef4444;        /* 警告红 */

    /* 文本颜色 */
    --text-main: #f1f5f9;
    --text-muted: #94a3b8;
    
    /* 边框与圆角 */
    --border: #334155;
    --radius-md: 12px;
    --radius-lg: 16px;
    
    /* 布局 */
    --nav-height: 70px;
    
    /* 动画 */
    --transition: all 0.25s cubic-bezier(0.4, 0, 0.2, 1);
}

/* 基础重置 */
*, *::before, *::after {
    box-sizing: border-box;
    margin: 0;
    padding: 0;
}

body {
    font-family: -apple-system, BlinkMacSystemFont, "Segoe UI", Roboto, "Helvetica Neue", Arial, sans-serif;
    background-color: var(--bg-body);
    color: var(--text-main);
    line-height: 1.7;
    -webkit-font-smoothing: antialiased;
    min-height: 100vh;
    display: flex;
    flex-direction: column;
    padding-top: var(--nav-height); /* 给固定导航栏留出空间 */
}

a { text-decoration: none; color: inherit; transition: var(--transition); }
ul { list-style: none; }
img { max-width: 100%; display: block; }

/* 强力无障碍焦点样式 */
a:focus-visible, button:focus-visible {
    outline: 3px solid var(--primary);
    outline-offset: 4px;
    border-radius: 4px;
}

/* 容器 */
.container {
    max-width: 1080px;
    margin: 0 auto;
    padding: 0 24px;
}

/* ==============================
   2. 导航栏 (新增)
   ============================== */
.main-nav {
    position: fixed;
    top: 0;
    left: 0;
    width: 100%;
    height: var(--nav-height);
    background: rgba(15, 17, 21, 0.85);
    backdrop-filter: blur(12px);
    border-bottom: 1px solid var(--border);
    z-index: 1000;
    display: flex;
    align-items: center;
}

.nav-content {
    display: flex;
    justify-content: space-between;
    align-items: center;
    width: 100%;
}

.nav-brand {
    font-size: 1.5rem;
    font-weight: 800;
    color: #fff;
    display: flex;
    align-items: center;
    gap: 10px;
}

.nav-links {
    display: flex;
    gap: 30px;
}

.nav-links a {
    color: var(--text-muted);
    font-weight: 500;
    font-size: 0.95rem;
    padding: 5px 0;
    position: relative;
}

.nav-links a:hover, .nav-links a.active {
    color: #fff;
}

.nav-links a.active::after {
    content: '';
    position: absolute;
    bottom: 0;
    left: 0;
    width: 100%;
    height: 2px;
    background: var(--primary);
    box-shadow: 0 0 10px var(--primary);
}

/* ==============================
   3. 通用组件
   ============================== */
/* 按钮 */
.btn {
    display: inline-flex;
    align-items: center;
    justify-content: center;
    padding: 12px 24px;
    font-size: 1rem;
    font-weight: 600;
    border-radius: 8px;
    cursor: pointer;
    transition: var(--transition);
    border: none;
    text-align: center;
}

.btn-primary {
    background-color: var(--primary);
    color: white;
    box-shadow: 0 4px 12px rgba(59, 130, 246, 0.3);
}
.btn-primary:hover {
    background-color: var(--primary-hover);
    transform: translateY(-1px);
}

.btn-secondary {
    background-color: var(--bg-surface-hover);
    color: var(--text-main);
    border: 1px solid var(--border);
}
.btn-secondary:hover {
    background-color: var(--border);
    color: white;
}

.btn-full { width: 100%; }

/* 卡片 */
.card {
    background-color: var(--bg-surface);
    border: 1px solid var(--border);
    border-radius: var(--radius-md);
    padding: 30px;
    margin-bottom: 24px;
    transition: var(--transition);
}

.card:hover {
    border-color: var(--primary);
    transform: translateY(-2px);
    box-shadow: 0 10px 25px -5px rgba(0, 0, 0, 0.3);
}

.section-title {
    font-size: 1.75rem;
    margin: 50px 0 30px;
    padding-bottom: 15px;
    border-bottom: 1px solid var(--border);
    color: #fff;
    display: flex;
    align-items: center;
}
.section-title::before {
    content: '';
    display: inline-block;
    width: 6px;
    height: 24px;
    background: var(--primary);
    margin-right: 12px;
    border-radius: 3px;
    box-shadow: 0 0 10px var(--primary);
}

/* ==============================
   4. 首页特定样式
   ============================== */
.hero-section {
    padding: 80px 0;
    text-align: center;
    background: radial-gradient(circle at center top, #1e293b 0%, var(--bg-body) 70%);
}

.clock-container {
    margin-bottom: 40px;
    user-select: none;
    cursor: default;
}
.clock-time {
    font-family: ui-monospace, SFMono-Regular, Menlo, monospace;
    font-size: 4rem;
    font-weight: 700;
    line-height: 1;
    letter-spacing: -2px;
    text-shadow: 0 0 20px rgba(59, 130, 246, 0.3);
    font-variant-numeric: tabular-nums;
}
.clock-date {
    margin-top: 8px;
    font-size: 1.1rem;
    color: var(--text-muted);
    font-weight: 500;
    letter-spacing: 2px;
    text-transform: uppercase;
}

.logo-large {
    width: 140px;
    height: 140px;
    margin: 0 auto 24px;
    background: var(--bg-surface);
    border-radius: 28px;
    display: flex;
    align-items: center;
    justify-content: center;
    border: 1px solid var(--border);
    box-shadow: 0 15px 40px rgba(0,0,0,0.4);
}

/* ==============================
   5. 下载页与模型页
   ============================== */
.download-hero {
    background: linear-gradient(180deg, #111827 0%, #0f1115 100%);
    border: 1px solid #1f2937;
    padding: 50px;
    text-align: center;
    border-radius: var(--radius-lg);
    margin: 40px 0;
}

.model-grid {
    display: grid;
    grid-template-columns: repeat(auto-fill, minmax(280px, 1fr));
    gap: 24px;
}
.model-card {
    background: var(--bg-surface);
    border: 1px solid var(--border);
    border-radius: var(--radius-md);
    padding: 24px;
    display: flex;
    flex-direction: column;
    justify-content: space-between;
}
.model-header { border-bottom: 1px solid #2d3748; padding-bottom: 15px; margin-bottom: 15px; }
.model-header h4 { margin: 0 0 5px 0; color: var(--primary); font-size: 1.2rem; }
.model-spec { font-size: 0.9rem; color: var(--text-muted); }

/* ==============================
   6. 页脚
   ============================== */
footer {
    margin-top: auto;
    padding: 50px 0 30px;
    border-top: 1px solid var(--border);
    text-align: center;
    background-color: #0d0f12;
    color: #64748b;
}
.footer-stats {
    display: flex;
    justify-content: center;
    gap: 15px;
    margin-top: 15px;
    font-size: 0.85rem;
}
.stat-item {
    background: rgba(255,255,255,0.03);
    padding: 5px 12px;
    border-radius: 12px;
}

/* 响应式 */
@media (max-width: 768px) {
    .main-nav { height: auto; padding: 10px 0; }
    .nav-content { flex-direction: column; gap: 15px; }
    .clock-time { font-size: 2.5rem; }
    .hero-section { padding: 40px 0; }
    .nav-links { gap: 15px; font-size: 0.9rem; }
}