* {
    margin: 0;
    padding: 0;
    box-sizing: border-box;
}

:root {
    --primary-color: #667eea;
    --secondary-color: #764ba2;
    --accent-color: #f093fb;
    --text-dark: #2c3e50;
    --text-light: #7f8c8d;
    --bg-light: #f5f7fa;
    --bg-white: #ffffff;
    --border-color: #e0e6ed;
    --success-color: #28a745;
    --danger-color: #dc3545;
    --warning-color: #ffc107;
}

body {
    font-family: 'Segoe UI', Tahoma, Geneva, Verdana, sans-serif;
    line-height: 1.6;
    color: var(--text-dark);
    background: var(--bg-light);
    overflow-x: hidden;
}

.container {
    max-width: 1200px;
    margin: 0 auto;
    padding: 0 20px;
}

.header {
    background: linear-gradient(135deg, var(--primary-color) 0%, var(--secondary-color) 100%);
    padding: 20px 0;
    position: fixed;
    top: 0;
    left: 0;
    right: 0;
    z-index: 1000;
    box-shadow: 0 2px 20px rgba(0,0,0,0.1);
}

.nav {
    display: flex;
    justify-content: space-between;
    align-items: center;
}

.logo {
    display: flex;
    align-items: center;
    gap: 12px;
    color: white;
    font-size: 24px;
    font-weight: 700;
}

.logo i {
    font-size: 28px;
}

.nav-links {
    display: flex;
    gap: 30px;
}

.nav-link {
    color: rgba(255,255,255,0.9);
    text-decoration: none;
    font-size: 16px;
    font-weight: 500;
    transition: all 0.3s ease;
    padding: 8px 16px;
    border-radius: 25px;
}

.nav-link:hover,
.nav-link.active {
    color: white;
    background: rgba(255,255,255,0.2);
}

.hero {
    background: linear-gradient(135deg, var(--primary-color) 0%, var(--secondary-color) 100%);
    padding: 150px 0 100px;
    text-align: center;
    color: white;
    position: relative;
    overflow: hidden;
}

.hero::before {
    content: '';
    position: absolute;
    top: 0;
    left: 0;
    right: 0;
    bottom: 0;
    background: url('data:image/svg+xml,<svg xmlns="http://www.w3.org/2000/svg" viewBox="0 0 100 100"><defs><pattern id="grain" width="100" height="100" patternUnits="userSpaceOnUse"><circle cx="25" cy="25" r="1" fill="rgba(255,255,255,0.1)"/><circle cx="75" cy="75" r="1" fill="rgba(255,255,255,0.1)"/><circle cx="50" cy="10" r="0.5" fill="rgba(255,255,255,0.05)"/><circle cx="10" cy="50" r="0.5" fill="rgba(255,255,255,0.05)"/><circle cx="90" cy="30" r="0.5" fill="rgba(255,255,255,0.05)"/></pattern></defs><rect width="100" height="100" fill="url(%23grain)"/></svg>');
}

.hero-content {
    position: relative;
    z-index: 1;
}

.hero-title {
    font-size: 48px;
    font-weight: 700;
    margin-bottom: 20px;
    text-shadow: 0 2px 10px rgba(0,0,0,0.2);
}

.hero-subtitle {
    font-size: 20px;
    opacity: 0.9;
    margin-bottom: 40px;
}

.hero-features {
    display: flex;
    justify-content: center;
    gap: 50px;
    flex-wrap: wrap;
}

.feature {
    display: flex;
    flex-direction: column;
    align-items: center;
    gap: 10px;
}

.feature i {
    font-size: 36px;
    color: rgba(255,255,255,0.9);
}

.feature span {
    font-size: 16px;
    font-weight: 600;
}

.plans {
    padding: 80px 0;
    background: var(--bg-light);
}

.section-header {
    text-align: center;
    margin-bottom: 50px;
}

.section-header h2 {
    font-size: 36px;
    color: var(--text-dark);
    margin-bottom: 15px;
}

.section-header p {
    font-size: 18px;
    color: var(--text-light);
}

.udid-input-section {
    background: var(--bg-white);
    padding: 30px;
    border-radius: 12px;
    margin-bottom: 50px;
    box-shadow: 0 4px 20px rgba(0,0,0,0.05);
    text-align: center;
}

.udid-input-section label {
    display: block;
    font-size: 18px;
    font-weight: 600;
    color: var(--text-dark);
    margin-bottom: 15px;
}

.udid-input-section label i {
    margin-right: 10px;
    color: var(--primary-color);
}

.udid-input-section input {
    width: 100%;
    max-width: 500px;
    padding: 15px 20px;
    border: 2px solid var(--border-color);
    border-radius: 10px;
    font-size: 16px;
    transition: all 0.3s ease;
}

.udid-input-section input:focus {
    outline: none;
    border-color: var(--primary-color);
    box-shadow: 0 0 0 3px rgba(102, 126, 234, 0.1);
}

.udid-hint {
    margin-top: 10px;
    font-size: 14px;
    color: var(--text-light);
}

.plans-grid {
    display: grid;
    grid-template-columns: 1fr;
    gap: 20px;
    margin-bottom: 30px;
}

.plan-card {
    background: var(--bg-white);
    border-radius: 12px;
    overflow: hidden;
    box-shadow: 0 2px 15px rgba(0,0,0,0.08);
    transition: all 0.3s ease;
    border: 2px solid transparent;
    position: relative;
}

.plan-card:hover {
    transform: translateY(-5px);
    box-shadow: 0 5px 25px rgba(0,0,0,0.12);
}

.plan-card.popular {
    border-color: var(--primary-color);
    transform: scale(1.02);
}

.plan-card.popular::before {
    content: '热门';
    position: absolute;
    top: 15px;
    right: -25px;
    background: linear-gradient(135deg, var(--primary-color), var(--secondary-color));
    color: white;
    padding: 4px 30px;
    transform: rotate(45deg);
    font-size: 11px;
    font-weight: 600;
    z-index: 10;
}

.plan-header {
    background: linear-gradient(135deg, var(--primary-color), var(--secondary-color));
    padding: 22px 20px;
    text-align: center;
    color: white;
}

.plan-title {
    font-size: 20px;
    font-weight: 700;
    margin-bottom: 8px;
}

.plan-price {
    font-size: 28px;
    font-weight: 700;
}

.plan-body {
    padding: 20px;
}

.plan-description {
    color: var(--text-light);
    line-height: 1.6;
    font-size: 14px;
}

.plan-footer {
    padding: 0 20px 20px;
    text-align: center;
}

.buy-btn {
    width: 100%;
    padding: 12px 20px;
    background: linear-gradient(135deg, var(--primary-color), var(--secondary-color));
    color: white;
    border: none;
    border-radius: 8px;
    font-size: 15px;
    font-weight: 600;
    cursor: pointer;
    transition: all 0.3s ease;
}

.buy-btn:hover {
    transform: translateY(-2px);
    box-shadow: 0 4px 15px rgba(102, 126, 234, 0.35);
}

.not-available {
    display: inline-block;
    padding: 12px 25px;
    background: var(--border-color);
    color: var(--text-light);
    border-radius: 8px;
    font-size: 13px;
}

.about {
    padding: 80px 0;
    background: var(--bg-white);
}

.about-content {
    display: grid;
    grid-template-columns: repeat(auto-fit, minmax(280px, 1fr));
    gap: 30px;
    margin-top: 50px;
}

.about-card {
    text-align: center;
    padding: 40px 20px;
    border-radius: 12px;
    transition: all 0.3s ease;
}

.about-card:hover {
    background: var(--bg-light);
    transform: translateY(-5px);
}

.about-card i {
    font-size: 48px;
    color: var(--primary-color);
    margin-bottom: 20px;
}

.about-card h3 {
    font-size: 22px;
    color: var(--text-dark);
    margin-bottom: 15px;
}

.about-card p {
    color: var(--text-light);
    line-height: 1.8;
}

.footer {
    background: var(--text-dark);
    color: white;
    padding: 30px 0;
    text-align: center;
}

.footer-content p {
    opacity: 0.8;
}

.modal {
    display: none;
    position: fixed;
    top: 0;
    left: 0;
    right: 0;
    bottom: 0;
    background: rgba(0,0,0,0.5);
    z-index: 2000;
    align-items: center;
    justify-content: center;
    padding: 20px;
}

.modal.active {
    display: flex;
}

.modal-content {
    background: var(--bg-white);
    border-radius: 15px;
    max-width: 500px;
    width: 100%;
    box-shadow: 0 10px 50px rgba(0,0,0,0.2);
    animation: modalSlideIn 0.3s ease;
}

@keyframes modalSlideIn {
    from {
        opacity: 0;
        transform: translateY(-50px);
    }
    to {
        opacity: 1;
        transform: translateY(0);
    }
}

.modal-header {
    display: flex;
    justify-content: space-between;
    align-items: center;
    padding: 25px 30px;
    border-bottom: 1px solid var(--border-color);
}

.modal-header h3 {
    font-size: 22px;
    color: var(--text-dark);
}

.close-modal {
    background: none;
    border: none;
    font-size: 28px;
    color: var(--text-light);
    cursor: pointer;
    transition: color 0.3s ease;
}

.close-modal:hover {
    color: var(--danger-color);
}

.modal-body {
    padding: 30px;
}

.modal-body p {
    margin-bottom: 15px;
    font-size: 16px;
    color: var(--text-dark);
}

.modal-body span {
    font-weight: 600;
    color: var(--primary-color);
}

.modal-footer {
    display: flex;
    justify-content: flex-end;
    gap: 15px;
    padding: 25px 30px;
    border-top: 1px solid var(--border-color);
}

.cancel-btn {
    padding: 12px 25px;
    background: var(--border-color);
    color: var(--text-dark);
    border: none;
    border-radius: 8px;
    font-size: 14px;
    cursor: pointer;
    transition: all 0.3s ease;
}

.cancel-btn:hover {
    background: var(--text-light);
    color: white;
}

.confirm-btn {
    padding: 12px 25px;
    background: var(--primary-color);
    color: white;
    border: none;
    border-radius: 8px;
    font-size: 14px;
    cursor: pointer;
    transition: all 0.3s ease;
}

.confirm-btn:hover {
    background: var(--secondary-color);
}

.error-message {
    background: #f8d7da;
    color: #721c24;
    padding: 20px;
    border-radius: 10px;
    text-align: center;
    font-size: 16px;
}

@media (max-width: 768px) {
    .container {
        padding: 0 15px;
    }

    .logo span {
        font-size: 20px;
    }

    .nav-links {
        gap: 15px;
    }

    .hero {
        padding: 130px 0 90px;
    }

    .nav-link {
        font-size: 14px;
        padding: 6px 12px;
    }

    .hero-title {
        font-size: 32px;
    }

    .hero-subtitle {
        font-size: 16px;
    }

    .hero-features {
        gap: 30px;
    }

    .plans-grid {
        grid-template-columns: 1fr;
        gap: 15px;
    }

    .plan-card {
        border-radius: 10px;
    }

    .plan-card.popular {
        transform: none;
    }

    .plan-header {
        padding: 18px 16px;
    }

    .plan-title {
        font-size: 18px;
    }

    .plan-price {
        font-size: 24px;
    }

    .plan-body {
        padding: 16px;
    }

    .plan-description {
        font-size: 13px;
    }

    .plan-footer {
        padding: 0 16px 16px;
    }

    .buy-btn {
        padding: 11px 18px;
        font-size: 14px;
    }

    .section-header h2 {
        font-size: 28px;
    }

    .udid-input-section input {
        max-width: 100%;
    }
}

@media (max-width: 480px) {
    .container {
        padding: 0 12px;
    }

    .logo span {
        display: none;
    }

    .nav-links {
        gap: 8px;
    }

    .nav-link {
        font-size: 13px;
        padding: 5px 10px;
    }

    .hero {
        padding: 110px 0 70px;
    }

    .hero-title {
        font-size: 24px;
    }

    .hero-subtitle {
        font-size: 14px;
    }

    .plans-grid {
        gap: 12px;
    }

    .plan-card {
        border-radius: 8px;
    }

    .plan-header {
        padding: 16px 14px;
    }

    .plan-title {
        font-size: 17px;
    }

    .plan-price {
        font-size: 22px;
    }

    .plan-body {
        padding: 14px;
    }

    .plan-description {
        font-size: 12px;
    }

    .plan-footer {
        padding: 0 14px 14px;
    }

    .buy-btn {
        padding: 10px 16px;
        font-size: 14px;
    }

    .plans {
        padding: 50px 0;
    }

    .about {
        padding: 50px 0;
    }

    .section-header h2 {
        font-size: 24px;
    }
}