:root {
        --primary: #4f46e5;
        --primary-soft: rgba(79, 70, 229, 0.1);
        --primary-strong: #4338ca;
        --bg: #f3f6ff;
        --panel: rgba(255,255,255,0.95);
        --text: #0f172a;
        --muted: #64748b;
        --line: rgba(148, 163, 184, 0.22);
        --card-shadow: 0 25px 50px -12px rgba(15,23,42,0.08);
    }
    body[data-theme="dark"] {
        --primary: #818cf8;
        --primary-soft: rgba(129,140,248,0.14);
        --primary-strong: #6366f1;
        --bg: #0b1220;
        --panel: rgba(15,23,42,0.94);
        --text: #f1f5f9;
        --muted: #94a3b8;
        --line: rgba(148, 163, 184, 0.24);
        --card-shadow: 0 25px 50px -12px rgba(0,0,0,0.5);
    }
    body {
        background-color: var(--bg);
        color: var(--text);
        font-family: -apple-system, BlinkMacSystemFont, "Segoe UI", "PingFang SC", "Microsoft YaHei", sans-serif;
        line-height: 1.6;
        transition: background 0.3s, color 0.3s;
    }
    .contact-container {
        max-width: 900px;
        margin: 48px auto 80px;
        padding: 0 12px;
    }
    .contact-card {
        background: var(--panel);
        border-radius: 32px;
        border: 1px solid var(--line);
        padding: 48px;
        box-shadow: var(--card-shadow);
        position: relative;
        overflow: hidden;
    }
    .contact-card::before {
        content: "";
        position: absolute;
        top: -40%;
        right: -10%;
        width: 400px;
        height: 400px;
        background: radial-gradient(circle, rgba(79,70,229,0.18) 0%, transparent 70%);
        pointer-events: none;
    }
    .contact-header {
        text-align: center;
        margin-bottom: 40px;
        position: relative;
        z-index: 1;
    }
    .contact-icon-header {
        width: 64px;
        height: 64px;
        border-radius: 18px;
        background: linear-gradient(135deg, #4f46e5, #7c3aed);
        display: inline-flex;
        align-items: center;
        justify-content: center;
        font-size: 32px;
        margin-bottom: 20px;
        box-shadow: 0 16px 32px rgba(79,70,229,0.25);
    }
    .contact-title {
        font-size: 36px;
        font-weight: 800;
        color: var(--text);
        margin-bottom: 12px;
        letter-spacing: -0.02em;
    }
    .contact-subtitle {
        color: var(--muted);
        font-size: 16px;
        max-width: 520px;
        margin: 0 auto;
    }
    .contact-grid {
        display: grid;
        grid-template-columns: repeat(auto-fit, minmax(260px, 1fr));
        gap: 20px;
        margin-top: 40px;
        position: relative;
        z-index: 1;
    }
    .contact-item {
        background: rgba(255,255,255,0.6);
        padding: 28px 24px;
        border-radius: 24px;
        text-align: center;
        border: 1px solid var(--line);
        transition: all 0.25s ease;
        text-decoration: none;
        display: flex;
        flex-direction: column;
        gap: 10px;
    }
    body[data-theme="dark"] .contact-item {
        background: rgba(30,41,59,0.6);
    }
    .contact-item:hover {
        transform: translateY(-5px);
        border-color: rgba(79,70,229,0.45);
        box-shadow: 0 16px 32px rgba(15,23,42,0.1);
    }
    body[data-theme="dark"] .contact-item:hover {
        box-shadow: 0 16px 32px rgba(0,0,0,0.4);
    }
    .contact-icon {
        font-size: 36px;
        display: block;
    }
    .contact-label {
        font-size: 13px;
        font-weight: 700;
        color: var(--muted);
        text-transform: uppercase;
        letter-spacing: 0.08em;
        display: block;
    }
    .contact-value {
        font-size: 18px;
        font-weight: 800;
        color: var(--text);
        word-break: break-all;
    }
    .contact-hint {
        font-size: 13px;
        color: var(--muted);
        margin-top: 6px;
    }
    .contact-footer {
        text-align: center;
        margin-top: 40px;
        padding-top: 32px;
        border-top: 1px dashed var(--line);
        position: relative;
        z-index: 1;
    }
    .back-btn {
        display: inline-flex;
        align-items: center;
        gap: 8px;
        padding: 12px 24px;
        background: linear-gradient(135deg, #4f46e5, #7c3aed);
        color: #fff;
        border-radius: 16px;
        text-decoration: none;
        font-weight: 800;
        transition: all 0.2s;
        box-shadow: 0 10px 25px rgba(79,70,229,0.25);
    }
    .back-btn:hover {
        transform: translateY(-2px);
        box-shadow: 0 16px 32px rgba(79,70,229,0.35);
    }
    @media (max-width: 640px) {
        .contact-card {
            padding: 32px 24px;
        }
        .contact-title {
            font-size: 28px;
        }
    }