/* =============================================
   app 布局专用样式 — 芯片选型 / 工具箱
   ============================================= */

:root {
    --brand-blue: #2563eb;
    --brand-purple: #7c3aed;
    --brand-pink: #db2777;
    --text-primary: #1e293b;
    --text-secondary: #64748b;
    --text-muted: #94a3b8;
    --border-color: #e5e7eb;
    --bg-page: #fafbfc;
}

/* ===== Main Content ===== */
.app-main { flex: 1; }
.app-content { max-width: 1400px; margin: 0 auto; padding: 0 24px; }

/* ===== Header ===== */
.app-header { position: sticky; top: 0; z-index: 100; background: rgba(255,255,255,0.92); backdrop-filter: blur(12px); border-bottom: 1px solid var(--border-color); }
.app-header-inner { max-width: 1400px; margin: 0 auto; padding: 0 24px; height: 56px; display: flex; align-items: center; justify-content: space-between; }
.app-logo { display: flex; align-items: center; gap: 10px; text-decoration: none; color: var(--text-primary); }
.app-logo-icon svg { display: block; }
.app-logo-text { font-weight: 700; font-size: 16px; }
.app-logo-text .sep { font-weight: 400; opacity: 0.3; margin: 0 6px; }
.app-logo-text .sub { font-size: 13px; font-weight: 500; }
.app-nav { display: flex; align-items: center; gap: 6px; }
.app-nav-link { padding: 6px 14px; border-radius: 8px; font-size: 13px; font-weight: 500; color: var(--text-secondary); text-decoration: none; transition: all .15s; }
.app-nav-link:hover { color: var(--text-primary); background: rgba(0,0,0,.03); }
.app-nav-link.active { color: var(--brand-blue); background: rgba(37,99,235,.08); }

/* ===== User Button ===== */
.app-user-btn { display: flex; align-items: center; gap: 8px; padding: 4px 14px 4px 4px; border-radius: 20px; font-size: 13px; font-weight: 500; color: var(--text-primary); background: #f1f5f9; border: none; cursor: pointer; text-decoration: none; transition: all .15s; }
.app-user-btn:hover { background: #e2e8f0; color: var(--text-primary); }
.app-user-avatar { width: 28px; height: 28px; border-radius: 50%; background: linear-gradient(135deg, var(--brand-blue), var(--brand-purple)); color: #fff; display: flex; align-items: center; justify-content: center; font-size: 12px; font-weight: 600; text-transform: uppercase; }
.app-login-btn { display: inline-flex; align-items: center; gap: 6px; padding: 7px 16px; border-radius: 20px; font-size: 13px; font-weight: 500; color: #fff; background: var(--brand-blue); border: none; cursor: pointer; text-decoration: none; transition: all .15s; }
.app-login-btn:hover { background: #1d4ed8; color: #fff; }

/* ===== Footer ===== */
.app-footer { background: #fff; border-top: 1px solid var(--border-color); padding: 40px 0 24px; margin-top: 40px; }
.app-footer-inner { max-width: 1400px; margin: 0 auto; padding: 0 24px; }
.app-footer-grid { display: grid; grid-template-columns: 2fr 1fr 1fr 1fr; gap: 32px; margin-bottom: 24px; }
.app-footer-brand-desc { font-size: 13px; color: var(--text-secondary); line-height: 1.6; margin: 10px 0; }
.app-footer-col-title { font-size: 13px; font-weight: 600; color: var(--text-primary); margin-bottom: 12px; }
.app-footer-link { display: block; font-size: 13px; color: var(--text-secondary); text-decoration: none; padding: 3px 0; transition: color .15s; }
.app-footer-link:hover { color: var(--brand-blue); }
.app-footer-bottom { font-size: 12px; color: var(--text-muted); padding-top: 16px; border-top: 1px solid var(--border-color); }

/* ===== Responsive ===== */
@media (max-width: 768px) {
    .app-footer-grid { grid-template-columns: 1fr 1fr; gap: 20px; }
    .app-nav { display: none; }
}