/* === 纸飞机下载中心 专属样式表 === */
:root {
    --accent-color: #0088cc;
    --text-dark: #0f172a;
    --text-muted: #64748b;
    --bg-aside: #f8fafc;
    --bg-main: #ffffff;
    --border-line: #e2e8f0;
    --success-color: #10b981;
    --warning-color: #f59e0b;
    --card-bg: #ffffff;
    --hover-shadow: 0 10px 25px rgba(0,136,204,0.04);
    --radius-md: 12px;
    --radius-sm: 8px;
}
* { box-sizing: border-box; margin: 0; padding: 0; }
body { font-family: -apple-system, BlinkMacSystemFont, "Segoe UI", Roboto, "Helvetica Neue", sans-serif; color: var(--text-dark); background: var(--bg-main); line-height: 1.6; }

/* 侧边栏布局（与首页完全一致） */
.app-container { display: flex; min-height: 100vh; }

aside { width: 340px; background: var(--bg-aside); border-right: 1px solid var(--border-line); padding: 40px 30px; display: flex; flex-direction: column; justify-content: space-between; position: fixed; top: 0; bottom: 0; left: 0; z-index: 10; overflow-y: auto; }
.brand-section .logo-link { font-size: 24px; font-weight: 800; color: var(--accent-color); text-decoration: none; display: flex; align-items: center; gap: 8px; letter-spacing: -0.5px; }
.brand-section .site-intro { font-size: 13px; color: var(--text-muted); margin-top: 15px; text-align: justify; line-height: 1.7; }

.side-nav { margin-top: 40px; }
.side-nav ul { list-style: none; display: flex; flex-direction: column; gap: 6px; }
.side-nav a { display: flex; align-items: center; justify-content: space-between; text-decoration: none; color: #334155; font-weight: 600; font-size: 14px; padding: 10px 14px; border-radius: var(--radius-sm); transition: all 0.2s; }
.side-nav a:hover, .side-nav a.active { background: #fff; color: var(--accent-color); box-shadow: 0 4px 12px rgba(15,23,42,0.03); }
.side-nav a::after { content: "→"; opacity: 0; transform: translateX(-5px); transition: all 0.2s; font-weight: 400; }
.side-nav a:hover::after, .side-nav a.active::after { opacity: 1; transform: translateX(0); }

.aside-meta { font-size: 12px; color: #94a3b8; border-top: 1px solid var(--border-line); padding-top: 25px; }
.aside-meta a { color: var(--text-muted); text-decoration: none; display: inline-block; margin-bottom: 6px; transition: color 0.2s; }
.aside-meta a:hover { color: var(--accent-color); }
.aside-meta p { margin-top: 8px; line-height: 1.5; }

/* 主内容区域 */
main { margin-left: 340px; flex: 1; padding: 60px 80px; max-width: 1100px; }

.breadcrumb-trail { font-size: 13px; color: var(--text-muted); margin-bottom: 30px; }
.breadcrumb-trail a { color: var(--text-muted); text-decoration: none; }
.breadcrumb-trail a:hover { color: var(--accent-color); }

/* 页面头部 */
.view-header { margin-bottom: 50px; }
.view-header h1 { font-size: 38px; font-weight: 800; letter-spacing: -1px; color: var(--text-dark); line-height: 1.2; margin-bottom: 15px; }
.view-header p { font-size: 18px; color: var(--text-muted); font-weight: 400; }

/* ========== 下载平台卡片网格 ========== */
.download-platform-grid { display: grid; grid-template-columns: repeat(2, 1fr); gap: 24px; margin-bottom: 60px; }
.platform-card { background: var(--card-bg); border: 1px solid var(--border-line); border-radius: var(--radius-md); padding: 28px; display: flex; flex-direction: column; transition: all 0.2s; }
.platform-card:hover { border-color: var(--accent-color); box-shadow: var(--hover-shadow); }
.platform-icon { font-size: 36px; margin-bottom: 15px; }
.platform-card h2 { font-size: 20px; font-weight: 700; color: var(--text-dark); margin-bottom: 6px; }
.platform-sub { font-size: 13px; color: var(--text-muted); margin-bottom: 18px; }
.platform-meta { list-style: none; display: grid; grid-template-columns: 1fr 1fr; gap: 10px; margin-bottom: 24px; font-size: 13px; color: #334155; }
.platform-meta li span { color: var(--text-muted); margin-right: 4px; font-weight: 500; }
.btn-download { display: flex; align-items: center; justify-content: center; background: var(--accent-color); color: #fff; text-decoration: none; padding: 12px; border-radius: 8px; font-weight: 700; font-size: 14px; transition: background 0.2s; margin-top: auto; }
.btn-download:hover { background: #0077b3; }
.btn-secondary-dl { background: #f1f5f9; color: #334155; }
.btn-secondary-dl:hover { background: #e2e8f0; }
.ios-notice { background: #fffbeb; border-left: 4px solid var(--warning-color); padding: 10px 14px; margin-top: 14px; font-size: 12px; color: #b45309; border-radius: 0 6px 6px 0; }

/* ========== 版本更新亮点 ========== */
.update-highlights { margin-bottom: 60px; padding: 30px 0; border-top: 1px solid var(--border-line); border-bottom: 1px solid var(--border-line); }
.section-title { font-size: 24px; font-weight: 800; color: var(--text-dark); margin-bottom: 25px; display: flex; align-items: center; gap: 8px; }
.highlights-grid { display: grid; grid-template-columns: repeat(4, 1fr); gap: 20px; }
.highlight-item { background: var(--card-bg); border: 1px solid var(--border-line); border-radius: var(--radius-sm); padding: 20px; transition: all 0.2s; }
.highlight-item:hover { border-color: var(--accent-color); box-shadow: var(--hover-shadow); }
.highlight-date { font-size: 11px; color: var(--accent-color); font-weight: 700; text-transform: uppercase; margin-bottom: 10px; display: block; }
.highlight-item h3 { font-size: 15px; font-weight: 700; color: var(--text-dark); margin-bottom: 8px; }
.highlight-item p { font-size: 13px; color: var(--text-muted); line-height: 1.5; }

/* ========== 三步安装指南 ========== */
.install-guide { margin-bottom: 60px; }
.guide-steps { display: flex; flex-direction: column; gap: 20px; }
.step { display: flex; gap: 20px; align-items: flex-start; }
.step-number { width: 44px; height: 44px; background: var(--accent-color); color: #fff; font-weight: 800; font-size: 20px; display: flex; align-items: center; justify-content: center; border-radius: 50%; flex-shrink: 0; }
.step-content h3 { font-size: 18px; font-weight: 700; color: var(--text-dark); margin-bottom: 6px; }
.step-content p { font-size: 14px; color: var(--text-muted); line-height: 1.7; }

/* ========== 安全下载提醒 ========== */
.security-reminder { margin-bottom: 60px; }
.reminder-card { background: #fef9e7; border: 1px solid #fde68a; border-radius: var(--radius-md); padding: 25px 30px; }
.reminder-card p { font-size: 14px; color: #78350f; line-height: 1.8; margin-bottom: 12px; }
.reminder-card a { color: var(--accent-color); font-weight: 600; text-decoration: none; }
.reminder-card a:hover { text-decoration: underline; }

/* SEO 深度文本 */
.seo-manifesto { border-top: 1px solid var(--border-line); padding-top: 50px; }
.seo-manifesto h3 { font-size: 22px; font-weight: 800; color: var(--text-dark); margin-top: 30px; margin-bottom: 16px; }
.seo-manifesto p { font-size: 15px; color: #334155; margin-bottom: 18px; text-align: justify; line-height: 1.8; }

/* 响应式设计 */
@media (max-width: 1024px) {
    aside { width: 260px; padding: 30px 20px; }
    main { margin-left: 260px; padding: 40px 40px; }
    .download-platform-grid, .highlights-grid { grid-template-columns: 1fr; }
}
@media (max-width: 768px) {
    .app-container { flex-direction: column; }
    aside { width: 100%; position: relative; border-right: none; border-bottom: 1px solid var(--border-line); padding: 30px 20px; }
    .side-nav { margin-top: 20px; }
    .side-nav ul { flex-direction: row; flex-wrap: wrap; gap: 8px; }
    .side-nav a { padding: 6px 12px; font-size: 13px; }
    .side-nav a::after { display: none; }
    main { margin-left: 0; padding: 30px 20px; }
    .view-header h1 { font-size: 28px; }
    .highlights-grid { grid-template-columns: 1fr; }
    .step { flex-direction: column; gap: 10px; }
}