:root {
    --primary-color: #0d6efd;
    --secondary-color: #6c757d;
    --success-color: #198754;
    --info-color: #0dcaf0;
    --warning-color: #ffc107;
    --danger-color: #dc3545;
    --light-color: #f8f9fa;
    --dark-color: #212529;
    --gradient-primary: linear-gradient(135deg, #667eea 0%, #764ba2 100%);
    --gradient-hero: linear-gradient(135deg, #667eea 0%, #764ba2 100%);
    --shadow-sm: 0 0.125rem 0.25rem rgba(0, 0, 0, 0.075);
    --shadow-md: 0 0.5rem 1rem rgba(0, 0, 0, 0.15);
    --shadow-lg: 0 1rem 3rem rgba(0, 0, 0, 0.175);
    --transition-base: all 0.3s ease;
}

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

html {
    scroll-behavior: smooth;
}

body {
    font-family: -apple-system, BlinkMacSystemFont, 'Segoe UI', 'Microsoft YaHei', sans-serif;
    line-height: 1.6;
    color: #333;
    overflow-x: hidden;
}

.navbar {
    box-shadow: var(--shadow-sm);
    backdrop-filter: blur(10px);
    background-color: rgba(13, 110, 253, 0.95) !important;
}

.navbar-brand {
    font-size: 1.5rem;
    font-weight: 700;
}

.logo-img {
    height: 40px;
    width: auto;
    object-fit: contain;
}

.nav-link {
    font-weight: 500;
    padding: 0.5rem 1rem !important;
    transition: var(--transition-base);
}

.nav-link:hover {
    color: rgba(255, 255, 255, 0.8) !important;
}

.hero-section {
    background: var(--gradient-hero);
    min-height: 100vh;
    display: flex;
    align-items: center;
    position: relative;
    overflow: hidden;
}

.hero-section::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 1440 320"><path fill="%23ffffff" fill-opacity="0.1" d="M0,96L48,112C96,128,192,160,288,160C384,160,480,128,576,122.7C672,117,768,139,864,154.7C960,171,1056,181,1152,165.3C1248,149,1344,107,1392,85.3L1440,64L1440,320L1392,320C1344,320,1248,320,1152,320C1056,320,960,320,864,320C768,320,672,320,576,320C480,320,384,320,288,320C192,320,96,320,48,320L0,320Z"></path></svg>');
    background-size: cover;
    background-position: bottom;
}

.hero-content {
    position: relative;
    z-index: 1;
    padding-top: 80px;
}

.qr-card {
    background: rgba(255, 255, 255, 0.15);
    backdrop-filter: blur(10px);
    border-radius: 20px;
    padding: 40px;
    display: inline-block;
    box-shadow: var(--shadow-lg);
    border: 1px solid rgba(255, 255, 255, 0.2);
}

.qr-image {
    background: white;
    padding: 20px;
    border-radius: 10px;
    display: inline-block;
}

.qr-image img {
    max-width: 200px;
    height: auto;
}

.stats-section {
    background: white;
    position: relative;
    margin-top: -50px;
    z-index: 10;
    border-radius: 20px 20px 0 0;
    box-shadow: var(--shadow-md);
}

.stat-item {
    padding: 20px;
}

.stat-item h3 {
    margin-bottom: 0.5rem;
}

.guide-section {
    background: white;
}

.guide-card {
    background: white;
    border-radius: 15px;
    padding: 30px;
    box-shadow: var(--shadow-md);
    transition: var(--transition-base);
    border: 1px solid #e9ecef;
    position: relative;
    overflow: hidden;
}

.guide-card:hover {
    transform: translateY(-5px);
    box-shadow: var(--shadow-lg);
}

.step-number {
    position: absolute;
    top: -20px;
    right: -20px;
    width: 80px;
    height: 80px;
    background: var(--gradient-primary);
    border-radius: 50%;
    display: flex;
    align-items: center;
    justify-content: center;
    color: white;
    font-size: 2.5rem;
    font-weight: 700;
    opacity: 0.2;
}

.tasks-section {
    background: var(--light-color);
}

.task-card {
    background: white;
    border-radius: 15px;
    overflow: hidden;
    box-shadow: var(--shadow-sm);
    transition: var(--transition-base);
    border: 1px solid #e9ecef;
}

.task-card:hover {
    transform: translateY(-5px);
    box-shadow: var(--shadow-md);
}

.task-header {
    background: var(--gradient-primary);
    color: white;
    padding: 20px;
    display: flex;
    justify-content: space-between;
    align-items: center;
}

.task-type {
    font-weight: 600;
    font-size: 1.1rem;
}

.task-price {
    font-size: 1.5rem;
    font-weight: 700;
}

.task-card .card-body {
    padding: 20px;
}

.task-footer {
    display: flex;
    justify-content: space-between;
    align-items: center;
    margin-top: 15px;
    padding-top: 15px;
    border-top: 1px solid #e9ecef;
}

.task-slots {
    color: var(--secondary-color);
    font-size: 0.9rem;
}

.task-types-section {
    background: white;
}

.type-card {
    background: white;
    border-radius: 15px;
    padding: 30px;
    text-align: center;
    box-shadow: var(--shadow-sm);
    transition: var(--transition-base);
    border: 1px solid #e9ecef;
}

.type-card:hover {
    transform: translateY(-5px);
    box-shadow: var(--shadow-md);
}

.type-icon {
    width: 80px;
    height: 80px;
    margin: 0 auto 20px;
    background: var(--gradient-primary);
    border-radius: 50%;
    display: flex;
    align-items: center;
    justify-content: center;
    color: white;
}

.type-card h4 {
    margin-bottom: 10px;
}

.testimonials-section {
    background: var(--light-color);
}

.testimonial-card {
    background: white;
    border-radius: 15px;
    padding: 30px;
    box-shadow: var(--shadow-sm);
    transition: var(--transition-base);
    border: 1px solid #e9ecef;
}

.testimonial-card:hover {
    transform: translateY(-5px);
    box-shadow: var(--shadow-md);
}

.user-avatar {
    text-align: center;
    margin-bottom: 20px;
}

.avatar-circle {
    width: 60px;
    height: 60px;
    background: var(--gradient-primary);
    border-radius: 50%;
    display: flex;
    align-items: center;
    justify-content: center;
    color: white;
    font-size: 1.5rem;
    font-weight: 700;
    margin: 0 auto;
}

.user-stats {
    margin-top: 15px;
}

.features-section {
    background: white;
}

.feature-card {
    background: white;
    border-radius: 15px;
    padding: 30px;
    text-align: center;
    box-shadow: var(--shadow-sm);
    transition: var(--transition-base);
    border: 1px solid #e9ecef;
}

.feature-card:hover {
    transform: translateY(-5px);
    box-shadow: var(--shadow-md);
}

.feature-icon {
    width: 80px;
    height: 80px;
    margin: 0 auto 20px;
    background: var(--gradient-primary);
    border-radius: 50%;
    display: flex;
    align-items: center;
    justify-content: center;
    color: white;
}

.feature-card h4 {
    margin-bottom: 10px;
}

.download-section {
    background: var(--gradient-primary);
    position: relative;
    overflow: hidden;
}

.download-section::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 1440 320"><path fill="%23ffffff" fill-opacity="0.1" d="M0,192L48,197.3C96,203,192,213,288,229.3C384,245,480,267,576,250.7C672,235,768,181,864,181.3C960,181,1056,235,1152,234.7C1248,235,1344,181,1392,154.7L1440,128L1440,320L1392,320C1344,320,1248,320,1152,320C1056,320,960,320,864,320C768,320,672,320,576,320C480,320,384,320,288,320C192,320,96,320,48,320L0,320Z"></path></svg>');
    background-size: cover;
    background-position: bottom;
}

.download-section > .container {
    position: relative;
    z-index: 1;
}

.qr-download {
    display: inline-block;
    background: white;
    padding: 30px;
    border-radius: 20px;
    box-shadow: var(--shadow-lg);
}

.qr-download img {
    max-width: 250px;
    height: auto;
}

.footer-section {
    background: white;
    border-top: 1px solid #e9ecef;
}

.faq-section {
    background: var(--light-color);
}

.accordion-item {
    border: 1px solid #e9ecef;
    border-radius: 15px !important;
    overflow: hidden;
    box-shadow: var(--shadow-sm);
    transition: var(--transition-base);
}

.accordion-item:hover {
    box-shadow: var(--shadow-md);
}

.accordion-button {
    font-weight: 600;
    padding: 20px;
    background: white;
    color: #333;
    border: none;
}

.accordion-button:not(.collapsed) {
    background: var(--gradient-primary);
    color: white;
    box-shadow: none;
}

.accordion-button:focus {
    box-shadow: none;
    border-color: rgba(13, 110, 253, 0.25);
}

.accordion-button::after {
    filter: invert(1);
}

.accordion-button:not(.collapsed)::after {
    filter: invert(1);
}

.accordion-body {
    padding: 20px;
    color: #666;
    line-height: 1.8;
}

.footer-section a {
    transition: var(--transition-base);
}

.footer-section a:hover {
    color: var(--primary-color) !important;
}

.back-to-top {
    position: fixed;
    bottom: 30px;
    right: 30px;
    width: 50px;
    height: 50px;
    background: var(--gradient-primary);
    color: white;
    border-radius: 50%;
    display: flex;
    align-items: center;
    justify-content: center;
    box-shadow: var(--shadow-md);
    opacity: 0;
    visibility: hidden;
    transition: var(--transition-base);
    z-index: 1000;
    text-decoration: none;
}

.back-to-top.show {
    opacity: 1;
    visibility: visible;
}

.back-to-top:hover {
    transform: translateY(-5px);
    box-shadow: var(--shadow-lg);
}

.btn {
    transition: var(--transition-base);
    border-radius: 10px;
    padding: 12px 30px;
    font-weight: 600;
}

.btn:hover {
    transform: translateY(-2px);
    box-shadow: var(--shadow-md);
}

.btn-primary {
    background: var(--gradient-primary);
    border: none;
}

.btn-primary:hover {
    background: var(--gradient-primary);
    box-shadow: var(--shadow-lg);
}

.card {
    border: none;
    border-radius: 15px;
}

@media (max-width: 768px) {
    .hero-content {
        text-align: center;
        padding-top: 100px;
    }
    
    .hero-section {
        padding: 60px 0;
    }
    
    .qr-card {
        margin-top: 30px;
        padding: 30px;
    }
    
    .qr-image {
        padding: 15px;
    }
    
    .qr-image img {
        max-width: 180px;
    }
    
    .stats-section {
        margin-top: 0;
        border-radius: 0;
    }
    
    .stat-item {
        margin-bottom: 20px;
    }
    
    .guide-card,
    .task-card,
    .type-card,
    .testimonial-card,
    .feature-card {
        margin-bottom: 20px;
    }
    
    .back-to-top {
        bottom: 20px;
        right: 20px;
        width: 45px;
        height: 45px;
    }
    
    .display-4 {
        font-size: 2rem;
    }
    
    .display-5 {
        font-size: 1.75rem;
    }
    
    .navbar-brand {
        font-size: 1.25rem;
    }
    
    .logo-img {
        height: 35px;
    }
}

@media (max-width: 576px) {
    .navbar-brand {
        font-size: 1.1rem;
    }
    
    .logo-img {
        height: 32px;
    }
    
    .qr-card {
        padding: 20px;
    }
    
    .qr-image {
        padding: 10px;
    }
    
    .qr-image img {
        max-width: 150px;
    }
    
    .hero-section h1 {
        font-size: 1.75rem;
    }
    
    .hero-section p {
        font-size: 1rem;
    }
    
    .btn-lg {
        padding: 10px 20px;
        font-size: 1rem;
    }
    
    .task-header {
        flex-direction: column;
        text-align: center;
        gap: 10px;
    }
    
    .task-footer {
        flex-direction: column;
        gap: 10px;
        text-align: center;
    }
    
    .qr-download {
        padding: 20px;
    }
    
    .qr-download img {
        max-width: 200px;
    }
}

@media (min-width: 992px) {
    .hero-content {
        text-align: left;
    }
}

@media (min-width: 1400px) {
    .container {
        max-width: 1320px;
    }
}

section {
    padding: 80px 0;
}

@media (max-width: 768px) {
    section {
        padding: 60px 0;
    }
}

.text-gradient {
    background: var(--gradient-primary);
    -webkit-background-clip: text;
    -webkit-text-fill-color: transparent;
    background-clip: text;
}

.bg-gradient {
    background: var(--gradient-primary);
}

.shadow-custom {
    box-shadow: var(--shadow-md);
}

.rounded-custom {
    border-radius: 15px;
}

.animate-fade-in {
    animation: fadeIn 0.6s ease-in;
}

@keyframes fadeIn {
    from {
        opacity: 0;
        transform: translateY(20px);
    }
    to {
        opacity: 1;
        transform: translateY(0);
    }
}