/* common.css — ToDesk 项目公共样式 | sd-todesk.com.cn */
:root {
    --primary: #0070F9; --primary-dark: #0056cc; --accent: #00D6E1;
    --secondary: #0175FF; --deep-blue: #1765D1; --green: #36BA78;
    --bg-dark: #080c14; --bg-card: #111827; --bg-card-hover: #1a2332;
    --bg-section: #0d1119; --text-primary: #e8eaed; --text-secondary: #9ca3af;
    --text-muted: #6b7280; --border: #1f2937;
    --gradient-hero: linear-gradient(135deg, #080c14 0%, #0d1b3e 50%, #080c14 100%);
    --gradient-blue: linear-gradient(135deg, #0070F9, #00D6E1);
    --gradient-card: linear-gradient(180deg, #111827 0%, #0f1729 100%);
    --shadow: 0 4px 24px rgba(0,112,249,0.1);
    --shadow-hover: 0 8px 40px rgba(0,112,249,0.2);
}
* { margin:0; padding:0; box-sizing:border-box; }
body {
    font-family: -apple-system, BlinkMacSystemFont, "Segoe UI", "PingFang SC", "Microsoft YaHei", sans-serif;
    background: var(--bg-dark); color: var(--text-primary); line-height: 1.6;
}
a { text-decoration: none; color: inherit; }
img { max-width: 100%; height: auto; display: block; }
.container { max-width: 1200px; margin: 0 auto; padding: 0 24px; }

/* Header */
header {
    position: fixed; top: 0; left: 0; right: 0; z-index: 1000;
    background: rgba(8,12,20,0.92); backdrop-filter: blur(16px);
    border-bottom: 1px solid var(--border); transition: all 0.3s;
}
header .container { display: flex; align-items: center; justify-content: space-between; height: 64px; }
.logo { display: flex; align-items: center; gap: 10px; }
.logo img, .logo svg { width: 128px; height: 28px; }
.logo-text { font-size: 18px; font-weight: 700; color: var(--text-primary); }
nav { display: flex; align-items: center; gap: 32px; }
nav a { color: var(--text-secondary); font-size: 15px; font-weight: 500; transition: color 0.2s; position: relative; padding: 4px 0; }
nav a:hover, nav a.active { color: var(--primary); }
nav a.active::after { content: ''; position: absolute; bottom: -4px; left: 0; right: 0; height: 2px; background: var(--gradient-blue); border-radius: 1px; }
.nav-cta { background: var(--gradient-blue); color: #fff !important; padding: 8px 20px !important; border-radius: 8px; font-weight: 600 !important; transition: opacity 0.2s, transform 0.2s; }
.nav-cta:hover { opacity: 0.9; transform: translateY(-1px); }
.mobile-toggle { display: none; background: none; border: none; color: var(--text-primary); font-size: 24px; cursor: pointer; }

/* Page Hero */
.page-hero { padding: 140px 0 80px; background: var(--gradient-hero); position: relative; overflow: hidden; text-align: center; }
.page-hero::before { content: ''; position: absolute; top: -40%; right: -15%; width: 500px; height: 500px; background: radial-gradient(circle, rgba(0,214,225,0.06) 0%, transparent 70%); border-radius: 50%; }
.page-hero h1 { font-size: 40px; font-weight: 800; margin-bottom: 16px; position: relative; background: linear-gradient(135deg, #ffffff 0%, #a0c4ff 100%); -webkit-background-clip: text; -webkit-text-fill-color: transparent; background-clip: text; }
.page-hero p { font-size: 17px; color: var(--text-secondary); max-width: 680px; margin: 0 auto; position: relative; }

/* Section */
.section { padding: 80px 0; }
.section-dark { background: var(--bg-section); }
.section-title { font-size: 28px; font-weight: 700; text-align: center; margin-bottom: 12px; }
.section-desc { text-align: center; color: var(--text-secondary); font-size: 15px; margin-bottom: 48px; }

/* Buttons */
.btn { display: inline-flex; align-items: center; gap: 8px; padding: 14px 32px; border-radius: 10px; font-size: 16px; font-weight: 600; cursor: pointer; transition: all 0.3s; border: none; text-decoration: none; }
.btn-primary { background: var(--gradient-blue); color: #fff; box-shadow: 0 4px 20px rgba(0,112,249,0.3); }
.btn-primary:hover { transform: translateY(-2px); box-shadow: 0 6px 28px rgba(0,112,249,0.4); }
.btn-outline { background: transparent; color: var(--text-primary); border: 1px solid var(--border); }
.btn-outline:hover { border-color: var(--primary); background: rgba(0,112,249,0.05); }
.btn-dl { display: inline-flex; align-items: center; justify-content: center; gap: 8px; width: 100%; padding: 14px; border-radius: 10px; font-size: 16px; font-weight: 600; cursor: pointer; transition: all 0.3s; border: none; color: #fff; text-align: center; text-decoration: none; }
.btn-blue { background: var(--gradient-blue); box-shadow: 0 4px 20px rgba(0,112,249,0.3); }
.btn-blue:hover { transform: translateY(-2px); box-shadow: 0 6px 28px rgba(0,112,249,0.4); }
.btn-outline-blue { background: transparent; border: 1px solid var(--primary); color: var(--primary); }
.btn-outline-blue:hover { background: rgba(0,112,249,0.08); }

/* Footer */
footer { background: var(--bg-card); border-top: 1px solid var(--border); padding: 60px 0 32px; }
.footer-grid { display: grid; grid-template-columns: 2fr 1fr 1fr 1fr; gap: 40px; }
.footer-brand p { font-size: 14px; color: var(--text-secondary); line-height: 1.7; }
.footer-col h4 { font-size: 16px; font-weight: 600; margin-bottom: 20px; }
.footer-col a { display: block; font-size: 14px; color: var(--text-secondary); margin-bottom: 12px; transition: color 0.2s; }
.footer-col a:hover { color: var(--primary); }
.footer-bottom { margin-top: 48px; padding-top: 24px; border-top: 1px solid var(--border); text-align: center; font-size: 13px; color: var(--text-muted); }

/* Responsive */
@media (max-width: 768px) {
    .page-hero h1 { font-size: 28px; }
    .footer-grid { grid-template-columns: 1fr 1fr; }
    nav { display: none; }
    nav.open { display: flex; flex-direction: column; position: absolute; top: 64px; left: 0; right: 0; background: var(--bg-dark); border-bottom: 1px solid var(--border); padding: 20px; }
    .mobile-toggle { display: block; }
}