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

:root {
    --primary-color: #2d8cf0;
    --primary-dark: #1b6fd0;
    --secondary-color: #19be6b;
    --dark-color: #17233d;
    --light-color: #f8f8f9;
    --gray-color: #808695;
    --border-color: #e8eaec;
    --transition: all 0.3s ease;
    --shadow: 0 4px 12px rgba(0, 0, 0, 0.08);
    --shadow-hover: 0 8px 24px rgba(0, 0, 0, 0.12);
    --card-border-radius: 10px;
}

html {
    scroll-behavior: smooth;
}

body {
    font-family: 'PingFang SC', 'Helvetica Neue', Arial, sans-serif;
    line-height: 1.6;
    color: var(--dark-color);
    background-color: #fff;
    overflow-x: hidden;
}

.container {
    width: 100%;
    max-width: 1200px;
    margin: 0 auto;
    padding: 0 20px;
}

/* Typography */
h1, h2, h3, h4 {
    font-weight: 600;
    line-height: 1.3;
    margin-bottom: 1rem;
}

h1 {
    font-size: 2.8rem;
    color: var(--dark-color);
}

h2 {
    font-size: 2.2rem;
    position: relative;
    padding-bottom: 15px;
}

h2:after {
    content: '';
    position: absolute;
    left: 0;
    bottom: 0;
    width: 50px;
    height: 3px;
    background: var(--primary-color);
}

h3 {
    font-size: 1.5rem;
    color: var(--dark-color);
}

p {
    margin-bottom: 1rem;
    color: var(--gray-color);
}

a {
    text-decoration: none;
    color: inherit;
    transition: var(--transition);
}

ul {
    list-style: none;
}

/* Button Styles */
.btn {
    display: inline-flex;
    align-items: center;
    justify-content: center;
    padding: 12px 28px;
    border-radius: 6px;
    font-weight: 500;
    font-size: 1rem;
    text-align: center;
    cursor: pointer;
    transition: var(--transition);
    border: none;
    outline: none;
    gap: 8px;
}

.btn-primary {
    background-color: var(--primary-color);
    color: white;
}

.btn-primary:hover {
    background-color: var(--primary-dark);
    transform: translateY(-2px);
    box-shadow: var(--shadow-hover);
}

.btn-outline {
    background-color: transparent;
    color: var(--primary-color);
    border: 1px solid var(--primary-color);
}

.btn-outline:hover {
    background-color: rgba(45, 140, 240, 0.05);
    transform: translateY(-2px);
    box-shadow: var(--shadow-hover);
}

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

.btn-secondary:hover {
    background-color: #18b566;
    transform: translateY(-2px);
    box-shadow: var(--shadow-hover);
}

/* Header & Navigation */
.main-nav {
    position: fixed;
    top: 0;
    left: 0;
    width: 100%;
    background-color: rgba(255, 255, 255, 0.98);
    box-shadow: 0 2px 10px rgba(0, 0, 0, 0.05);
    z-index: 1000;
    padding: 15px 0;
}

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

.logo a {
    display: flex;
    align-items: center;
    font-size: 1.8rem;
    font-weight: 700;
    color: var(--primary-color);
    gap: 10px;
}

.logo-icon {
    width: 32px;
    height: 32px;
    background-color: var(--primary-color);
    border-radius: 6px;
    display: flex;
    align-items: center;
    justify-content: center;
    color: white;
}

.nav-download-btn {
    display: inline-flex;
    align-items: center;
    justify-content: center;
    padding: 10px 24px;
    border-radius: 6px;
    font-weight: 500;
    font-size: 1rem;
    background-color: var(--secondary-color);
    color: white;
    transition: var(--transition);
    gap: 8px;
}

.nav-download-btn:hover {
    background-color: #18b566;
    transform: translateY(-2px);
    box-shadow: var(--shadow-hover);
}

/* Hero Section */
.intro-banner {
    padding: 160px 0 100px;
    background: linear-gradient(135deg, #f5f7fa 0%, #e4edf5 100%);
    overflow: hidden;
}

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

.banner-text {
    flex: 1;
    min-width: 300px;
    padding-right: 40px;
}

.banner-image {
    flex: 1;
    min-width: 300px;
    text-align: center;
}

.banner-image img {
    max-width: 100%;
    height: auto;
    border-radius: 15px;
    box-shadow: var(--shadow-hover);
    transition: transform 0.5s ease;
}

.banner-image img:hover {
    transform: translateY(-5px);
}

.intro-text {
    margin-bottom: 30px;
}

.intro-text p {
    font-size: 1.1rem;
    margin-bottom: 15px;
}

.update-time {
    font-size: 0.9rem;
    color: var(--gray-color);
    margin-top: 20px;
}

.action-btns {
    display: grid;
    grid-template-columns: repeat(2, 1fr);
    gap: 15px;
    margin-top: 30px;
}

.action-btns .btn {
    width: 100%;
}

/* Download Section */
.download-section {
    padding: 100px 0;
    background-color: var(--light-color);
}

.download-section h2 {
    text-align: center;
    margin-bottom: 50px;
}

.download-section h2:after {
    left: 50%;
    transform: translateX(-50%);
}

.download-options {
    display: grid;
    grid-template-columns: repeat(auto-fit, minmax(300px, 1fr));
    gap: 30px;
}

.download-card {
    background: white;
    border-radius: var(--card-border-radius);
    padding: 30px;
    box-shadow: var(--shadow);
    transition: var(--transition);
    border-top: 4px solid var(--primary-color);
}

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

.download-card:nth-child(2) {
    border-top-color: var(--secondary-color);
}

.download-card-header {
    display: flex;
    align-items: center;
    margin-bottom: 20px;
    gap: 15px;
}

.download-icon {
    width: 50px;
    height: 50px;
    background: linear-gradient(135deg, var(--primary-color), #5cadff);
    border-radius: 10px;
    display: flex;
    align-items: center;
    justify-content: center;
    color: white;
    font-size: 22px;
}

.download-card:nth-child(2) .download-icon {
    background: linear-gradient(135deg, var(--secondary-color), #36d483);
}

.feature-list li {
    padding: 10px 0;
    border-bottom: 1px solid var(--border-color);
    position: relative;
    padding-left: 28px;
}

.feature-list li:before {
    content: '✓';
    position: absolute;
    left: 0;
    color: var(--secondary-color);
    font-weight: bold;
    font-size: 1.1rem;
}

/* Features Section */
.features-section {
    padding: 100px 0;
}

.section-header {
    text-align: center;
    margin-bottom: 60px;
}

.section-header h2:after {
    left: 50%;
    transform: translateX(-50%);
}

.section-desc {
    max-width: 700px;
    margin: 0 auto 30px;
    font-size: 1.1rem;
}

.features-grid {
    display: grid;
    grid-template-columns: repeat(2, 1fr);
    gap: 30px;
}

@media (max-width: 768px) {
    .features-grid {
        grid-template-columns: 1fr;
    }
}

.feature-card {
    background: white;
    border-radius: var(--card-border-radius);
    padding: 30px;
    box-shadow: var(--shadow);
    transition: var(--transition);
    border-top: 4px solid var(--primary-color);
}

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

.feature-card:nth-child(2) {
    border-top-color: var(--secondary-color);
}

.feature-card:nth-child(3) {
    border-top-color: #ff9900;
}

.feature-card:nth-child(4) {
    border-top-color: #ed4014;
}

.feature-icon {
    width: 60px;
    height: 60px;
    background: linear-gradient(135deg, var(--primary-color), #5cadff);
    border-radius: 12px;
    display: flex;
    align-items: center;
    justify-content: center;
    margin-bottom: 20px;
    color: white;
    font-size: 24px;
}

.feature-card:nth-child(2) .feature-icon {
    background: linear-gradient(135deg, var(--secondary-color), #36d483);
}

.feature-card:nth-child(3) .feature-icon {
    background: linear-gradient(135deg, #ff9900, #ffad33);
}

.feature-card:nth-child(4) .feature-icon {
    background: linear-gradient(135deg, #ed4014, #f16643);
}

.feature-details li {
    padding: 8px 0;
    border-bottom: 1px solid var(--border-color);
    position: relative;
    padding-left: 24px;
}

.feature-details li:before {
    content: '•';
    position: absolute;
    left: 0;
    color: var(--primary-color);
    font-weight: bold;
    font-size: 1.2rem;
}

/* Guide Section */
.guide-section {
    padding: 100px 0;
    background-color: var(--light-color);
}

.guide-steps {
    display: grid;
    grid-template-columns: repeat(auto-fit, minmax(300px, 1fr));
    gap: 40px;
}

.guide-step {
    position: relative;
}

.step-number {
    position: absolute;
    top: -20px;
    left: -20px;
    font-size: 3rem;
    font-weight: 700;
    color: rgba(45, 140, 240, 0.1);
    z-index: 0;
}

.step-content {
    position: relative;
    z-index: 1;
    background: white;
    padding: 30px;
    border-radius: var(--card-border-radius);
    box-shadow: var(--shadow);
    height: 100%;
    border-top: 4px solid var(--primary-color);
}

.step-icon {
    width: 50px;
    height: 50px;
    background: linear-gradient(135deg, var(--secondary-color), #36d483);
    border-radius: 10px;
    display: flex;
    align-items: center;
    justify-content: center;
    margin-bottom: 20px;
    color: white;
    font-size: 20px;
}

/* Safe Section */
.safe-section {
    padding: 100px 0;
}

.safe-grid {
    display: grid;
    grid-template-columns: repeat(auto-fit, minmax(250px, 1fr));
    gap: 30px;
    margin-bottom: 60px;
}

.safe-card {
    background: white;
    border-radius: var(--card-border-radius);
    padding: 30px;
    box-shadow: var(--shadow);
    transition: var(--transition);
    border-top: 4px solid #ff9900;
}

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

.safe-card:nth-child(2) {
    border-top-color: #19be6b;
}

.safe-card:nth-child(3) {
    border-top-color: #2d8cf0;
}

.safe-card:nth-child(4) {
    border-top-color: #ed4014;
}

.safe-icon {
    width: 50px;
    height: 50px;
    background: linear-gradient(135deg, #ff9900, #ffad33);
    border-radius: 10px;
    display: flex;
    align-items: center;
    justify-content: center;
    margin-bottom: 20px;
    color: white;
    font-size: 20px;
}

.safe-card:nth-child(2) .safe-icon {
    background: linear-gradient(135deg, #19be6b, #36d483);
}

.safe-card:nth-child(3) .safe-icon {
    background: linear-gradient(135deg, #2d8cf0, #5cadff);
}

.safe-card:nth-child(4) .safe-icon {
    background: linear-gradient(135deg, #ed4014, #f16643);
}

.safe-stats {
    display: grid;
    grid-template-columns: repeat(auto-fit, minmax(200px, 1fr));
    gap: 30px;
    text-align: center;
}

.stat-item {
    padding: 30px;
    background: white;
    border-radius: var(--card-border-radius);
    box-shadow: var(--shadow);
    border-top: 4px solid var(--primary-color);
}

.stat-number {
    font-size: 2.5rem;
    font-weight: 700;
    color: var(--primary-color);
    margin-bottom: 10px;
}

/* Footer */
.site-footer {
    background-color: var(--dark-color);
    color: rgba(255, 255, 255, 0.7);
    padding: 30px 0;
    text-align: center;
    font-size: 0.9rem;
}

.footer-content p {
    color: rgba(255, 255, 255, 0.7);
    margin-bottom: 0;
}

/* Responsive Design */
@media (max-width: 992px) {
    h1 {
        font-size: 2.4rem;
    }
    
    h2 {
        font-size: 1.9rem;
    }
    
    .banner-text {
        padding-right: 0;
        margin-bottom: 50px;
    }
    
    .banner-content {
        flex-direction: column;
    }
    
    .action-btns {
        grid-template-columns: 1fr;
    }
}

@media (max-width: 768px) {
    .nav-download-btn {
        display: none;
    }
    
    .mobile-download-btn {
        display: flex;
        margin-top: 20px;
        width: 100%;
        justify-content: center;
    }
    
    .intro-banner {
        padding: 140px 0 80px;
    }
    
    .download-section, .features-section, .guide-section, .safe-section {
        padding: 80px 0;
    }
    
    .features-grid {
        grid-template-columns: 1fr;
    }
}

@media (max-width: 576px) {
    h1 {
        font-size: 2rem;
    }
    
    h2 {
        font-size: 1.6rem;
    }
    
    .btn {
        padding: 10px 20px;
        font-size: 0.95rem;
    }
    
    .download-options, .guide-steps, .safe-grid, .safe-stats {
        grid-template-columns: 1fr;
    }
    
    .download-card, .feature-card, .step-content, .safe-card, .stat-item {
        padding: 20px;
    }
}