/* ===== 3D打印服务平台 - 前台公共样式 ===== */
:root {
    --primary: #409eff;
    --primary-dark: #337ecc;
    --primary-light: #ecf5ff;
    --success: #67c23a;
    --warning: #e6a23c;
    --danger: #f56c6c;
    --text-main: #303133;
    --text-regular: #606266;
    --text-secondary: #909399;
    --border: #e4e7ed;
    --bg: #f5f7fa;
    --white: #ffffff;
    --radius: 12px;
    --radius-lg: 20px;
    --shadow-sm: 0 2px 12px rgba(0,0,0,0.04);
    --shadow: 0 8px 24px rgba(0,0,0,0.06);
    --shadow-lg: 0 20px 48px rgba(0,0,0,0.1);
}

* { margin: 0; padding: 0; box-sizing: border-box; }
html { scroll-behavior: smooth; }
body {
    font-family: 'Microsoft YaHei', 'PingFang SC', system-ui, -apple-system, sans-serif;
    background: var(--bg);
    color: var(--text-main);
    line-height: 1.6;
}

.container { max-width: 1200px; margin: 0 auto; padding: 0 20px; }

/* Header */
header {
    background: rgba(255,255,255,0.92);
    backdrop-filter: blur(12px);
    -webkit-backdrop-filter: blur(12px);
    border-bottom: 1px solid var(--border);
    position: fixed;
    width: 100%;
    top: 0;
    z-index: 1000;
}
.header-inner {
    display: flex;
    justify-content: space-between;
    align-items: center;
    padding: 18px 0;
}
.logo {
    font-size: 26px;
    font-weight: 800;
    color: var(--primary);
    text-decoration: none;
    display: flex;
    align-items: center;
    gap: 8px;
}
.logo::before {
    content: '◈';
    font-size: 28px;
    color: var(--primary);
}
nav a {
    color: var(--text-regular);
    text-decoration: none;
    margin-left: 32px;
    font-weight: 500;
    position: relative;
    transition: color 0.3s;
}
nav a:hover, nav a.active { color: var(--primary); }
nav a.active::after,
nav a:hover::after {
    content: '';
    position: absolute;
    bottom: -6px;
    left: 0;
    width: 100%;
    height: 2px;
    background: var(--primary);
    border-radius: 2px;
}

/* Buttons */
.btn {
    display: inline-flex;
    align-items: center;
    justify-content: center;
    gap: 8px;
    padding: 14px 32px;
    background: var(--primary);
    color: #fff;
    text-decoration: none;
    border-radius: var(--radius);
    font-weight: 600;
    border: none;
    cursor: pointer;
    transition: all 0.3s ease;
}
.btn:hover {
    background: var(--primary-dark);
    transform: translateY(-2px);
    box-shadow: 0 10px 24px rgba(64,158,255,0.28);
}
.btn-outline {
    background: transparent;
    color: var(--primary);
    border: 2px solid var(--primary);
}
.btn-outline:hover { background: var(--primary-light); }
.btn-white {
    background: #fff;
    color: var(--primary);
}
.btn-white:hover { background: #f0f7ff; }

/* Section */
section { padding: 90px 0; }
.section-title { text-align: center; margin-bottom: 55px; }
.section-title h2 {
    font-size: 36px;
    margin-bottom: 14px;
    color: var(--text-main);
}
.section-title p {
    color: var(--text-secondary);
    font-size: 16px;
    max-width: 560px;
    margin: 0 auto;
}
.section-tag {
    display: inline-block;
    padding: 6px 16px;
    background: var(--primary-light);
    color: var(--primary);
    border-radius: 20px;
    font-size: 13px;
    font-weight: 600;
    margin-bottom: 14px;
}

/* Footer */
footer {
    background: var(--white);
    border-top: 1px solid var(--border);
    padding: 50px 0 30px;
    color: var(--text-secondary);
}
.footer-grid {
    display: grid;
    grid-template-columns: 1.6fr 1fr 1fr 1fr;
    gap: 40px;
    margin-bottom: 40px;
}
.footer-brand .logo { margin-bottom: 16px; }
.footer-brand p { font-size: 14px; line-height: 1.8; }
.footer-title {
    font-size: 16px;
    font-weight: 700;
    color: var(--text-main);
    margin-bottom: 20px;
}
.footer-links { list-style: none; }
.footer-links li { margin-bottom: 12px; }
.footer-links a {
    color: var(--text-secondary);
    text-decoration: none;
    font-size: 14px;
    transition: color 0.3s;
}
.footer-links a:hover { color: var(--primary); }
.footer-bottom {
    border-top: 1px solid var(--border);
    padding-top: 24px;
    text-align: center;
    font-size: 14px;
}

/* Responsive */
@media (max-width: 992px) {
    .footer-grid { grid-template-columns: 1fr 1fr; }
}
@media (max-width: 768px) {
    .header-inner { flex-direction: column; gap: 14px; }
    nav a { margin-left: 0; margin-right: 18px; }
    section { padding: 60px 0; }
    .section-title h2 { font-size: 28px; }
    .footer-grid { grid-template-columns: 1fr; gap: 28px; }
}