:root {
    --primary: #2563eb;
    --primary-dark: #1d4ed8;
    --primary-light: #eff6ff;
    --accent: #f97316;
    --accent-dark: #ea580c;
    --green: #16a34a;
    --green-light: #f0fdf4;
    --gray-50: #f9fafb;
    --gray-100: #f3f4f6;
    --gray-200: #e5e7eb;
    --gray-300: #d1d5db;
    --gray-400: #9ca3af;
    --gray-500: #6b7280;
    --gray-600: #4b5563;
    --gray-700: #374151;
    --gray-800: #1f2937;
    --gray-900: #111827;
    --shadow: 0 1px 3px rgba(0,0,0,0.1), 0 1px 2px rgba(0,0,0,0.06);
    --shadow-md: 0 4px 6px -1px rgba(0,0,0,0.1), 0 2px 4px -1px rgba(0,0,0,0.06);
    --shadow-lg: 0 10px 15px -3px rgba(0,0,0,0.1), 0 4px 6px -2px rgba(0,0,0,0.05);
    --radius: 10px;
}

* { margin: 0; padding: 0; box-sizing: border-box; }
body { font-family: -apple-system, "PingFang SC", "Microsoft YaHei", "Helvetica Neue", sans-serif; background: var(--gray-50); color: var(--gray-800); -webkit-font-smoothing: antialiased; line-height: 1.6; }
a { text-decoration: none; color: inherit; }
img { max-width: 100%; display: block; }
ul, ol { list-style: none; }

/* ======== Header / Nav ======== */
.header {
    background: #fff;
    border-bottom: 1px solid var(--gray-200);
    position: sticky;
    top: 0;
    z-index: 100;
}
.header-inner {
    max-width: 1100px;
    margin: 0 auto;
    padding: 0 20px;
    height: 56px;
    display: flex;
    align-items: center;
    justify-content: space-between;
}
.logo {
    font-size: 18px;
    font-weight: 700;
    color: var(--primary);
    display: flex;
    align-items: center;
    gap: 8px;
}
.logo svg { flex-shrink: 0; }
.nav-links { display: flex; gap: 24px; }
.nav-links a {
    font-size: 14px;
    color: var(--gray-600);
    transition: color 0.2s;
    position: relative;
}
.nav-links a:hover, .nav-links a.active { color: var(--primary); }
.nav-links a.active::after {
    content: '';
    position: absolute;
    bottom: -17px;
    left: 0; right: 0;
    height: 2px;
    background: var(--primary);
    border-radius: 1px;
}

/* ======== Hero Banner ======== */
.hero {
    background: linear-gradient(135deg, #1e40af 0%, #3b82f6 50%, #60a5fa 100%);
    color: #fff;
    padding: 60px 20px 50px;
    text-align: center;
}
.hero h1 { font-size: 32px; font-weight: 700; margin-bottom: 12px; }
.hero .subtitle { font-size: 16px; opacity: 0.9; max-width: 600px; margin: 0 auto 8px; line-height: 1.6; }
.hero .company-tag {
    display: inline-block;
    margin-top: 14px;
    padding: 6px 16px;
    background: rgba(255,255,255,0.15);
    border-radius: 20px;
    font-size: 13px;
    backdrop-filter: blur(4px);
}

/* ======== Section Common ======== */
.section { max-width: 1100px; margin: 0 auto; padding: 50px 20px; }
.section-title {
    text-align: center;
    margin-bottom: 36px;
}
.section-title h2 {
    font-size: 24px;
    font-weight: 700;
    color: var(--gray-900);
    margin-bottom: 8px;
}
.section-title p {
    font-size: 14px;
    color: var(--gray-400);
}

/* ======== Product Grid ======== */
.product-grid {
    display: grid;
    grid-template-columns: repeat(2, 1fr);
    gap: 20px;
}
.product-card {
    background: #fff;
    border-radius: var(--radius);
    box-shadow: var(--shadow);
    overflow: hidden;
    transition: transform 0.2s, box-shadow 0.2s;
    display: flex;
    flex-direction: column;
}
.product-card:hover {
    transform: translateY(-4px);
    box-shadow: var(--shadow-lg);
}
.product-thumb {
    width: 100%;
    height: 180px;
    background: linear-gradient(135deg, var(--primary-light), #dbeafe);
    display: flex;
    align-items: center;
    justify-content: center;
    position: relative;
}
.product-thumb .thumb-icon {
    width: 64px;
    height: 64px;
    color: var(--primary);
    opacity: 0.7;
}
.product-badge {
    position: absolute;
    top: 12px;
    right: 12px;
    background: var(--accent);
    color: #fff;
    font-size: 11px;
    font-weight: 600;
    padding: 3px 10px;
    border-radius: 4px;
}
.product-info {
    padding: 20px;
    flex: 1;
    display: flex;
    flex-direction: column;
}
.product-info h3 {
    font-size: 17px;
    font-weight: 600;
    color: var(--gray-900);
    margin-bottom: 8px;
}
.product-info .desc {
    font-size: 13px;
    color: var(--gray-500);
    line-height: 1.6;
    flex: 1;
    margin-bottom: 14px;
}
.product-tags {
    display: flex;
    flex-wrap: wrap;
    gap: 6px;
    margin-bottom: 16px;
}
.product-tags span {
    font-size: 11px;
    padding: 3px 10px;
    background: var(--primary-light);
    color: var(--primary);
    border-radius: 4px;
    font-weight: 500;
}
.product-bottom {
    display: flex;
    align-items: center;
    justify-content: space-between;
    border-top: 1px solid var(--gray-100);
    padding-top: 14px;
}
.product-price {
    font-size: 22px;
    font-weight: 700;
    color: var(--accent);
}
.product-price small {
    font-size: 13px;
    font-weight: 400;
    color: var(--gray-400);
}
.btn {
    display: inline-flex;
    align-items: center;
    gap: 6px;
    padding: 8px 20px;
    border-radius: 6px;
    font-size: 13px;
    font-weight: 600;
    border: none;
    cursor: pointer;
    transition: all 0.2s;
    text-decoration: none;
}
.btn-primary {
    background: var(--primary);
    color: #fff;
}
.btn-primary:hover { background: var(--primary-dark); }
.btn-accent {
    background: var(--accent);
    color: #fff;
}
.btn-accent:hover { background: var(--accent-dark); }
.btn-outline {
    background: #fff;
    color: var(--primary);
    border: 1px solid var(--primary);
}
.btn-outline:hover { background: var(--primary-light); }
.btn-lg { padding: 12px 32px; font-size: 15px; border-radius: 8px; }
.btn-block { display: flex; width: 100%; justify-content: center; }

/* ======== Features Section ======== */
.features-grid {
    display: grid;
    grid-template-columns: repeat(4, 1fr);
    gap: 20px;
}
.feature-item {
    text-align: center;
    padding: 28px 16px;
    background: #fff;
    border-radius: var(--radius);
    box-shadow: var(--shadow);
}
.feature-icon {
    width: 48px;
    height: 48px;
    margin: 0 auto 14px;
    background: var(--primary-light);
    border-radius: 12px;
    display: flex;
    align-items: center;
    justify-content: center;
    color: var(--primary);
}
.feature-item h4 {
    font-size: 15px;
    font-weight: 600;
    color: var(--gray-800);
    margin-bottom: 6px;
}
.feature-item p {
    font-size: 12px;
    color: var(--gray-400);
    line-height: 1.5;
}

/* ======== About / Company ======== */
.about-card {
    background: #fff;
    border-radius: var(--radius);
    box-shadow: var(--shadow);
    padding: 36px;
    max-width: 800px;
    margin: 0 auto;
}
.about-card h3 {
    font-size: 18px;
    font-weight: 600;
    color: var(--gray-900);
    margin-bottom: 16px;
    display: flex;
    align-items: center;
    gap: 8px;
}
.about-card p {
    font-size: 14px;
    color: var(--gray-600);
    line-height: 1.8;
    margin-bottom: 14px;
}
.info-grid {
    display: grid;
    grid-template-columns: repeat(2, 1fr);
    gap: 12px;
    margin-top: 20px;
}
.info-item {
    padding: 14px 16px;
    background: var(--gray-50);
    border-radius: 8px;
}
.info-item .label {
    font-size: 12px;
    color: var(--gray-400);
    margin-bottom: 4px;
}
.info-item .value {
    font-size: 14px;
    color: var(--gray-800);
    font-weight: 500;
}

/* ======== Product Detail Page ======== */
.detail-wrap {
    max-width: 800px;
    margin: 0 auto;
    padding: 30px 20px;
}
.detail-card {
    background: #fff;
    border-radius: var(--radius);
    box-shadow: var(--shadow);
    overflow: hidden;
}
.detail-banner {
    height: 220px;
    display: flex;
    align-items: center;
    justify-content: center;
    position: relative;
}
.detail-banner.bg-blue { background: linear-gradient(135deg, #dbeafe, #bfdbfe); }
.detail-banner.bg-green { background: linear-gradient(135deg, #dcfce7, #bbf7d0); }
.detail-banner.bg-purple { background: linear-gradient(135deg, #f3e8ff, #e9d5ff); }
.detail-banner.bg-orange { background: linear-gradient(135deg, #ffedd5, #fed7aa); }
.detail-banner .detail-icon {
    width: 80px;
    height: 80px;
    opacity: 0.6;
}
.detail-badge {
    position: absolute;
    top: 16px;
    right: 16px;
    background: var(--accent);
    color: #fff;
    font-size: 12px;
    font-weight: 600;
    padding: 4px 14px;
    border-radius: 4px;
}
.detail-body { padding: 28px; }
.detail-body h1 {
    font-size: 22px;
    font-weight: 700;
    color: var(--gray-900);
    margin-bottom: 8px;
}
.detail-body .detail-desc {
    font-size: 14px;
    color: var(--gray-500);
    margin-bottom: 20px;
    line-height: 1.6;
}
.detail-price-row {
    display: flex;
    align-items: baseline;
    gap: 12px;
    margin-bottom: 24px;
    padding: 16px;
    background: #fffbeb;
    border-radius: 8px;
}
.detail-price {
    font-size: 28px;
    font-weight: 700;
    color: var(--accent);
}
.detail-price-note {
    font-size: 13px;
    color: var(--gray-400);
}

.detail-section { margin-bottom: 24px; }
.detail-section h3 {
    font-size: 15px;
    font-weight: 600;
    color: var(--gray-800);
    margin-bottom: 12px;
    padding-bottom: 8px;
    border-bottom: 1px solid var(--gray-100);
}
.detail-features {
    display: grid;
    grid-template-columns: repeat(2, 1fr);
    gap: 10px;
}
.detail-features li {
    font-size: 13px;
    color: var(--gray-600);
    padding: 8px 12px;
    background: var(--gray-50);
    border-radius: 6px;
    display: flex;
    align-items: center;
    gap: 8px;
}
.detail-features li .check {
    color: var(--green);
    font-weight: bold;
    flex-shrink: 0;
}

.detail-actions {
    display: flex;
    gap: 12px;
    margin-top: 28px;
    padding-top: 20px;
    border-top: 1px solid var(--gray-100);
}

/* ======== Pay Page ======== */
.pay-wrap {
    max-width: 600px;
    margin: 0 auto;
    padding: 30px 20px;
}
.pay-card {
    background: #fff;
    border-radius: var(--radius);
    box-shadow: var(--shadow);
    padding: 28px;
}
.pay-card h2 {
    font-size: 20px;
    font-weight: 700;
    color: var(--gray-900);
    margin-bottom: 24px;
    text-align: center;
}
.pay-item {
    display: flex;
    justify-content: space-between;
    align-items: center;
    padding: 14px 0;
    border-bottom: 1px solid var(--gray-100);
}
.pay-item:last-of-type { border-bottom: none; }
.pay-item .pay-label {
    font-size: 14px;
    color: var(--gray-600);
}
.pay-item .pay-value {
    font-size: 14px;
    color: var(--gray-900);
    font-weight: 500;
}
.pay-total {
    display: flex;
    justify-content: space-between;
    align-items: baseline;
    padding: 20px 0;
    margin-top: 8px;
    border-top: 2px solid var(--gray-200);
}
.pay-total .pay-label { font-size: 16px; font-weight: 600; color: var(--gray-800); }
.pay-total .pay-amount { font-size: 26px; font-weight: 700; color: var(--accent); }

.pay-methods {
    margin: 24px 0;
}
.pay-methods h4 {
    font-size: 14px;
    color: var(--gray-700);
    margin-bottom: 12px;
}
.pay-method-list { display: flex; gap: 12px; }
.pay-method {
    flex: 1;
    padding: 14px;
    border: 2px solid var(--gray-200);
    border-radius: 8px;
    text-align: center;
    cursor: pointer;
    transition: all 0.2s;
    background: #fff;
}
.pay-method.active {
    border-color: var(--green);
    background: var(--green-light);
}
.pay-method .pm-name {
    font-size: 14px;
    font-weight: 600;
    color: var(--gray-700);
    margin-top: 6px;
}
.pay-method .pm-icon {
    font-size: 24px;
}

.form-group { margin-bottom: 16px; }
.form-group label {
    display: block;
    font-size: 13px;
    color: var(--gray-600);
    margin-bottom: 6px;
    font-weight: 500;
}
.form-group input, .form-group select {
    width: 100%;
    padding: 10px 14px;
    border: 1px solid var(--gray-300);
    border-radius: 6px;
    font-size: 14px;
    outline: none;
    transition: border-color 0.2s;
}
.form-group input:focus, .form-group select:focus {
    border-color: var(--primary);
}

.pay-notice {
    margin-top: 20px;
    padding: 12px 16px;
    background: #fffbeb;
    border-radius: 8px;
    font-size: 12px;
    color: var(--gray-500);
    line-height: 1.6;
}

/* ======== Footer ======== */
.footer {
    background: var(--gray-800);
    color: var(--gray-400);
    padding: 36px 20px;
    margin-top: 50px;
}
.footer-inner {
    max-width: 1100px;
    margin: 0 auto;
    text-align: center;
}
.footer-links {
    display: flex;
    justify-content: center;
    gap: 24px;
    margin-bottom: 16px;
}
.footer-links a {
    font-size: 13px;
    color: var(--gray-400);
    transition: color 0.2s;
}
.footer-links a:hover { color: #fff; }
.footer-info {
    font-size: 12px;
    color: var(--gray-500);
    line-height: 1.8;
}
.footer-copy {
    margin-top: 16px;
    padding-top: 16px;
    border-top: 1px solid var(--gray-700);
    font-size: 12px;
    color: var(--gray-500);
}

/* ======== Responsive ======== */
@media (max-width: 768px) {
    .hero { padding: 40px 16px 36px; }
    .hero h1 { font-size: 24px; }
    .hero .subtitle { font-size: 14px; }
    .product-grid { grid-template-columns: 1fr; }
    .features-grid { grid-template-columns: repeat(2, 1fr); }
    .info-grid { grid-template-columns: 1fr; }
    .detail-features { grid-template-columns: 1fr; }
    .detail-actions { flex-direction: column; }
    .nav-links { gap: 16px; }
    .nav-links a { font-size: 13px; }
    .about-card { padding: 24px 18px; }
    .section { padding: 36px 16px; }
}

@media (max-width: 480px) {
    .header-inner { padding: 0 14px; }
    .logo { font-size: 16px; }
    .nav-links { gap: 12px; }
    .nav-links a { font-size: 12px; }
    .features-grid { grid-template-columns: 1fr; gap: 12px; }
    .product-thumb { height: 140px; }
    .pay-method-list { flex-direction: column; }
    .detail-banner { height: 160px; }
    .footer-links { flex-wrap: wrap; gap: 14px; }
}