/* ===== 币安下载网 - 品牌样式 ===== */
:root {
    --color-primary: #F0B90B;
    --color-primary-dark: #D4A509;
    --color-primary-light: #FFD54F;
    --color-secondary: #1A1A2E;
    --color-secondary-light: #16213E;
    --color-accent: #0F3460;
    --bg-primary: #FFFFFF;
    --bg-secondary: #F8F9FA;
    --bg-dark: #0D1117;
    --text-primary: #1A1A2E;
    --text-secondary: #4A4A6A;
    --text-muted: #8888A0;
    --border-color: #E5E7EB;
    --success: #10B981;
    --error: #EF4444;
    --warning: #F59E0B;
    --shadow-sm: 0 1px 3px rgba(0,0,0,0.08);
    --shadow-md: 0 4px 12px rgba(0,0,0,0.1);
    --shadow-lg: 0 8px 30px rgba(0,0,0,0.12);
    --shadow-xl: 0 20px 60px rgba(0,0,0,0.15);
    --radius-sm: 8px;
    --radius-md: 12px;
    --radius-lg: 16px;
    --radius-xl: 24px;
    --transition: all 0.3s cubic-bezier(0.4, 0, 0.2, 1);
    --font-sans: 'Inter', -apple-system, BlinkMacSystemFont, 'Segoe UI', Roboto, sans-serif;
}

/* ===== Reset & Base ===== */
*, *::before, *::after {
    margin: 0;
    padding: 0;
    box-sizing: border-box;
}

html {
    scroll-behavior: smooth;
    font-size: 16px;
}

body {
    font-family: var(--font-sans);
    color: var(--text-primary);
    background: var(--bg-primary);
    line-height: 1.6;
    -webkit-font-smoothing: antialiased;
    -moz-osx-font-smoothing: grayscale;
}

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

img {
    max-width: 100%;
    height: auto;
    display: block;
}

ul {
    list-style: none;
}

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

/* ===== Typography ===== */
h1, h2, h3, h4, h5, h6 {
    font-weight: 700;
    line-height: 1.2;
    color: var(--text-primary);
}

h1 { font-size: clamp(32px, 5vw, 48px); }
h2 { font-size: clamp(24px, 4vw, 36px); }
h3 { font-size: clamp(20px, 3vw, 28px); }
h4 { font-size: clamp(18px, 2.5vw, 24px); }

.section-header {
    text-align: center;
    margin-bottom: 48px;
}

.section-title {
    margin-bottom: 12px;
    position: relative;
    display: inline-block;
}

.section-title::after {
    content: '';
    display: block;
    width: 60px;
    height: 4px;
    background: linear-gradient(90deg, var(--color-primary), var(--color-primary-light));
    border-radius: 2px;
    margin: 12px auto 0;
}

.section-desc {
    color: var(--text-secondary);
    font-size: 1.1rem;
    max-width: 600px;
    margin: 0 auto;
}

/* ===== Buttons ===== */
.btn {
    display: inline-flex;
    align-items: center;
    justify-content: center;
    gap: 8px;
    padding: 12px 24px;
    border-radius: var(--radius-md);
    font-weight: 600;
    font-size: 1rem;
    border: 2px solid transparent;
    cursor: pointer;
    transition: var(--transition);
    text-decoration: none;
    white-space: nowrap;
    font-family: var(--font-sans);
}

.btn:active {
    transform: scale(0.97);
}

.btn-primary {
    background: linear-gradient(135deg, var(--color-primary), var(--color-primary-dark));
    color: var(--color-secondary);
    border-color: var(--color-primary);
}

.btn-primary:hover {
    background: linear-gradient(135deg, var(--color-primary-light), var(--color-primary));
    transform: translateY(-2px);
    box-shadow: 0 4px 20px rgba(240, 185, 11, 0.4);
}

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

.btn-outline:hover {
    background: var(--color-primary);
    color: var(--color-secondary);
    transform: translateY(-2px);
}

.btn-lg {
    padding: 16px 32px;
    font-size: 1.1rem;
    border-radius: var(--radius-lg);
}

.btn-full {
    width: 100%;
}

.btn-icon {
    width: 20px;
    height: 20px;
    flex-shrink: 0;
}

/* ===== Navbar ===== */
.navbar {
    position: fixed;
    top: 0;
    left: 0;
    right: 0;
    z-index: 1000;
    background: rgba(255, 255, 255, 0.95);
    backdrop-filter: blur(20px);
    -webkit-backdrop-filter: blur(20px);
    border-bottom: 1px solid transparent;
    transition: var(--transition);
}

.navbar.scrolled {
    border-bottom-color: var(--border-color);
    box-shadow: var(--shadow-sm);
}

.nav-container {
    display: flex;
    align-items: center;
    justify-content: space-between;
    height: 72px;
}

.nav-logo {
    display: flex;
    align-items: center;
    gap: 10px;
}

.logo-icon {
    width: 36px;
    height: 36px;
}

.logo-text {
    font-size: 1.25rem;
    font-weight: 700;
    color: var(--color-secondary);
}

.nav-menu {
    display: flex;
    align-items: center;
    gap: 8px;
}

.nav-menu a {
    padding: 8px 16px;
    border-radius: var(--radius-sm);
    font-weight: 500;
    color: var(--text-secondary);
    font-size: 0.95rem;
    position: relative;
}

.nav-menu a:hover,
.nav-menu a.active {
    color: var(--color-primary);
    background: rgba(240, 185, 11, 0.1);
}

.nav-toggle {
    display: none;
    flex-direction: column;
    gap: 5px;
    cursor: pointer;
    padding: 8px;
}

.nav-toggle span {
    display: block;
    width: 24px;
    height: 2px;
    background: var(--text-primary);
    border-radius: 2px;
    transition: var(--transition);
}

.nav-toggle.active span:nth-child(1) {
    transform: rotate(45deg) translate(5px, 5px);
}

.nav-toggle.active span:nth-child(2) {
    opacity: 0;
}

.nav-toggle.active span:nth-child(3) {
    transform: rotate(-45deg) translate(5px, -5px);
}

/* ===== Hero ===== */
.hero {
    padding: 120px 0 80px;
    background: linear-gradient(135deg, var(--color-secondary) 0%, var(--color-secondary-light) 50%, var(--color-accent) 100%);
    position: relative;
    overflow: hidden;
    min-height: 90vh;
    display: flex;
    align-items: center;
}

.hero-container {
    display: grid;
    grid-template-columns: 1fr 1fr;
    gap: 60px;
    align-items: center;
    position: relative;
    z-index: 2;
}

.hero-content {
    color: white;
}

.hero-logo {
    width: 180px;
    margin-bottom: 24px;
}

.hero-title {
    font-size: clamp(36px, 6vw, 56px);
    font-weight: 800;
    margin-bottom: 16px;
    background: linear-gradient(135deg, var(--color-primary), var(--color-primary-light));
    -webkit-background-clip: text;
    -webkit-text-fill-color: transparent;
    background-clip: text;
}

.hero-subtitle {
    font-size: 1.15rem;
    color: rgba(255, 255, 255, 0.8);
    line-height: 1.8;
    margin-bottom: 32px;
    max-width: 540px;
}

.hero-buttons {
    display: flex;
    gap: 16px;
    flex-wrap: wrap;
    margin-bottom: 40px;
}

.hero-stats {
    display: flex;
    gap: 40px;
}

.stat-item {
    text-align: center;
}

.stat-number {
    display: block;
    font-size: 1.75rem;
    font-weight: 800;
    color: var(--color-primary);
    margin-bottom: 4px;
}

.stat-label {
    font-size: 0.9rem;
    color: rgba(255, 255, 255, 0.6);
}

/* Hero Shapes */
.hero-visual {
    position: relative;
    height: 100%;
    min-height: 400px;
}

.hero-shapes {
    position: absolute;
    inset: 0;
}

.shape {
    position: absolute;
    border-radius: 50%;
    animation: float 6s ease-in-out infinite;
}

.shape-1 {
    width: 300px;
    height: 300px;
    background: radial-gradient(circle, rgba(240, 185, 11, 0.15), transparent);
    top: 10%;
    right: 10%;
    animation-delay: 0s;
}

.shape-2 {
    width: 200px;
    height: 200px;
    background: radial-gradient(circle, rgba(255, 255, 255, 0.05), transparent);
    bottom: 20%;
    right: 30%;
    animation-delay: 1s;
}

.shape-3 {
    width: 150px;
    height: 150px;
    border: 2px solid rgba(240, 185, 11, 0.2);
    top: 40%;
    right: 50%;
    animation-delay: 2s;
}

.shape-4 {
    width: 100px;
    height: 100px;
    background: rgba(240, 185, 11, 0.08);
    bottom: 40%;
    right: 15%;
    animation-delay: 3s;
}

@keyframes float {
    0%, 100% { transform: translateY(0) scale(1); }
    50% { transform: translateY(-20px) scale(1.05); }
}

.hero-wave {
    position: absolute;
    bottom: -2px;
    left: 0;
    right: 0;
    height: 100px;
    z-index: 1;
}

.hero-wave svg {
    width: 100%;
    height: 100%;
}

/* ===== Features ===== */
.features {
    padding: 100px 0;
    background: var(--bg-primary);
}

.features-grid {
    display: grid;
    grid-template-columns: repeat(auto-fit, minmax(260px, 1fr));
    gap: 24px;
}

.feature-card {
    padding: 32px;
    border-radius: var(--radius-lg);
    background: var(--bg-primary);
    border: 1px solid var(--border-color);
    transition: var(--transition);
    text-align: center;
}

.feature-card:hover {
    transform: translateY(-4px);
    box-shadow: var(--shadow-lg);
    border-color: var(--color-primary);
}

.feature-icon {
    width: 56px;
    height: 56px;
    margin: 0 auto 20px;
}

.feature-icon svg {
    width: 100%;
    height: 100%;
}

.feature-card h3 {
    margin-bottom: 12px;
    font-size: 1.25rem;
}

.feature-card p {
    color: var(--text-secondary);
    line-height: 1.7;
}

/* ===== Download ===== */
.download {
    padding: 100px 0;
    background: var(--bg-secondary);
}

.download-grid {
    display: grid;
    grid-template-columns: repeat(auto-fit, minmax(260px, 1fr));
    gap: 24px;
}

.download-card {
    padding: 36px 28px;
    border-radius: var(--radius-lg);
    background: var(--bg-primary);
    border: 1px solid var(--border-color);
    transition: var(--transition);
    text-align: center;
    display: flex;
    flex-direction: column;
    align-items: center;
}

.download-card:hover {
    transform: translateY(-4px);
    box-shadow: var(--shadow-lg);
    border-color: var(--color-primary);
}

.download-icon {
    width: 56px;
    height: 56px;
    margin-bottom: 20px;
}

.download-icon svg {
    width: 100%;
    height: 100%;
}

.download-card h3 {
    margin-bottom: 8px;
    font-size: 1.2rem;
}

.download-card > p {
    color: var(--text-secondary);
    margin-bottom: 16px;
    font-size: 0.9rem;
}

.download-info {
    display: flex;
    gap: 16px;
    margin-bottom: 24px;
    font-size: 0.85rem;
}

.version {
    background: rgba(240, 185, 11, 0.1);
    color: var(--color-primary-dark);
    padding: 4px 12px;
    border-radius: 20px;
    font-weight: 600;
}

.size {
    color: var(--text-muted);
    padding: 4px 12px;
    background: var(--bg-secondary);
    border-radius: 20px;
}

.download-btn {
    width: 100%;
}

/* ===== Articles ===== */
.articles {
    padding: 100px 0;
    background: var(--bg-primary);
}

.articles-grid {
    display: grid;
    grid-template-columns: repeat(auto-fit, minmax(340px, 1fr));
    gap: 24px;
}

.article-card {
    display: block;
    padding: 28px;
    border-radius: var(--radius-lg);
    background: var(--bg-primary);
    border: 1px solid var(--border-color);
    transition: var(--transition);
}

.article-card:hover {
    transform: translateY(-4px);
    box-shadow: var(--shadow-lg);
    border-color: var(--color-primary);
}

.article-category {
    display: inline-block;
    font-size: 0.8rem;
    font-weight: 600;
    color: var(--color-primary-dark);
    background: rgba(240, 185, 11, 0.1);
    padding: 4px 12px;
    border-radius: 20px;
    margin-bottom: 12px;
    text-transform: uppercase;
    letter-spacing: 0.5px;
}

.article-card h3 {
    font-size: 1.15rem;
    margin-bottom: 8px;
    line-height: 1.4;
}

.article-card p {
    color: var(--text-secondary);
    font-size: 0.9rem;
    line-height: 1.6;
    margin-bottom: 16px;
}

.article-meta {
    display: flex;
    justify-content: space-between;
    align-items: center;
    font-size: 0.85rem;
}

.article-date {
    color: var(--text-muted);
}

.article-read-more {
    color: var(--color-primary);
    font-weight: 600;
}

.no-articles {
    text-align: center;
    padding: 60px 20px;
    color: var(--text-muted);
}

/* ===== FAQ ===== */
.faq {
    padding: 100px 0;
    background: var(--bg-secondary);
}

.faq-list {
    max-width: 800px;
    margin: 0 auto;
    display: flex;
    flex-direction: column;
    gap: 12px;
}

.faq-item {
    background: var(--bg-primary);
    border-radius: var(--radius-md);
    border: 1px solid var(--border-color);
    overflow: hidden;
    transition: var(--transition);
}

.faq-item:hover {
    border-color: var(--color-primary);
}

.faq-question {
    display: flex;
    justify-content: space-between;
    align-items: center;
    padding: 20px 24px;
    cursor: pointer;
    font-weight: 600;
    font-size: 1.05rem;
    user-select: none;
}

.faq-arrow {
    width: 20px;
    height: 20px;
    transition: var(--transition);
    flex-shrink: 0;
}

.faq-item.active .faq-arrow {
    transform: rotate(180deg);
}

.faq-answer {
    max-height: 0;
    overflow: hidden;
    transition: max-height 0.3s ease, padding 0.3s ease;
    padding: 0 24px;
}

.faq-item.active .faq-answer {
    max-height: 300px;
    padding: 0 24px 20px;
}

.faq-answer p {
    color: var(--text-secondary);
    line-height: 1.7;
}

/* ===== Page Hero ===== */
.page-hero {
    padding: 120px 0 60px;
    background: linear-gradient(135deg, var(--color-secondary), var(--color-accent));
    text-align: center;
    color: white;
}

.page-hero h1 {
    color: white;
    margin-bottom: 12px;
}

.page-hero p {
    color: rgba(255, 255, 255, 0.7);
    font-size: 1.1rem;
}

/* ===== Contact ===== */
.contact-section {
    padding: 80px 0;
}

.contact-grid {
    display: grid;
    grid-template-columns: 1fr 1.5fr;
    gap: 60px;
    align-items: start;
}

.contact-info {
    display: flex;
    flex-direction: column;
    gap: 24px;
}

.contact-card {
    padding: 24px;
    border-radius: var(--radius-md);
    border: 1px solid var(--border-color);
    transition: var(--transition);
}

.contact-card:hover {
    border-color: var(--color-primary);
    box-shadow: var(--shadow-sm);
}

.contact-icon {
    width: 40px;
    height: 40px;
    margin-bottom: 16px;
}

.contact-icon svg {
    width: 100%;
    height: 100%;
}

.contact-card h3 {
    font-size: 1.1rem;
    margin-bottom: 8px;
}

.contact-card p {
    color: var(--text-secondary);
    font-size: 0.95rem;
    line-height: 1.6;
}

.contact-form-wrapper {
    padding: 32px;
    border-radius: var(--radius-lg);
    border: 1px solid var(--border-color);
    background: var(--bg-primary);
}

.contact-form-wrapper h2 {
    margin-bottom: 24px;
}

.form-group {
    margin-bottom: 20px;
}

.form-group label {
    display: block;
    margin-bottom: 6px;
    font-weight: 600;
    font-size: 0.95rem;
    color: var(--text-primary);
}

.form-group input,
.form-group select,
.form-group textarea {
    width: 100%;
    padding: 12px 16px;
    border: 2px solid var(--border-color);
    border-radius: var(--radius-sm);
    font-size: 1rem;
    font-family: var(--font-sans);
    transition: var(--transition);
    background: var(--bg-primary);
}

.form-group input:focus,
.form-group select:focus,
.form-group textarea:focus {
    outline: none;
    border-color: var(--color-primary);
    box-shadow: 0 0 0 3px rgba(240, 185, 11, 0.15);
}

.form-group textarea {
    resize: vertical;
    min-height: 120px;
}

.form-success {
    text-align: center;
    padding: 40px 20px;
}

.form-success svg {
    width: 64px;
    height: 64px;
    margin-bottom: 16px;
}

.form-success h3 {
    margin-bottom: 8px;
    color: var(--success);
}

.form-success p {
    color: var(--text-secondary);
}

/* ===== Footer ===== */
.footer {
    background: var(--color-secondary);
    color: rgba(255, 255, 255, 0.8);
    padding: 60px 0 0;
}

.footer-content {
    display: grid;
    grid-template-columns: 2fr 3fr;
    gap: 60px;
    padding-bottom: 40px;
    border-bottom: 1px solid rgba(255, 255, 255, 0.1);
}

.footer-logo {
    height: 32px;
    margin-bottom: 16px;
}

.footer-brand p {
    font-size: 0.9rem;
    line-height: 1.7;
    color: rgba(255, 255, 255, 0.6);
    margin-bottom: 20px;
}

.footer-social {
    display: flex;
    gap: 12px;
}

.social-link {
    display: flex;
    align-items: center;
    justify-content: center;
    width: 40px;
    height: 40px;
    border-radius: 50%;
    background: rgba(255, 255, 255, 0.1);
    color: rgba(255, 255, 255, 0.7);
    transition: var(--transition);
}

.social-link svg {
    width: 18px;
    height: 18px;
}

.social-link:hover {
    background: var(--color-primary);
    color: var(--color-secondary);
    transform: translateY(-2px);
}

.footer-links {
    display: grid;
    grid-template-columns: repeat(3, 1fr);
    gap: 32px;
}

.footer-col h4 {
    color: white;
    font-size: 1rem;
    margin-bottom: 16px;
}

.footer-col ul li {
    margin-bottom: 10px;
}

.footer-col ul li a {
    color: rgba(255, 255, 255, 0.6);
    font-size: 0.9rem;
    transition: var(--transition);
}

.footer-col ul li a:hover {
    color: var(--color-primary);
    padding-left: 4px;
}

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

.footer-bottom p {
    font-size: 0.85rem;
    color: rgba(255, 255, 255, 0.4);
}

/* ===== Responsive ===== */
@media (max-width: 1024px) {
    .hero-container {
        grid-template-columns: 1fr;
        text-align: center;
    }

    .hero-content {
        order: 2;
    }

    .hero-visual {
        order: 1;
        min-height: 300px;
    }

    .hero-subtitle {
        margin: 0 auto 32px;
    }

    .hero-buttons {
        justify-content: center;
    }

    .hero-stats {
        justify-content: center;
    }

    .contact-grid {
        grid-template-columns: 1fr;
    }
}

@media (max-width: 768px) {
    .nav-menu {
        position: fixed;
        top: 72px;
        left: 0;
        right: 0;
        background: rgba(255, 255, 255, 0.98);
        backdrop-filter: blur(20px);
        flex-direction: column;
        padding: 20px;
        gap: 4px;
        transform: translateY(-100%);
        opacity: 0;
        pointer-events: none;
        transition: var(--transition);
        box-shadow: var(--shadow-lg);
    }

    .nav-menu.active {
        transform: translateY(0);
        opacity: 1;
        pointer-events: all;
    }

    .nav-menu a {
        width: 100%;
        padding: 12px 16px;
        font-size: 1.05rem;
    }

    .nav-toggle {
        display: flex;
    }

    .hero {
        padding: 100px 0 60px;
        min-height: auto;
    }

    .hero-title {
        font-size: 2rem;
    }

    .hero-subtitle {
        font-size: 1rem;
    }

    .hero-stats {
        flex-wrap: wrap;
        gap: 24px;
    }

    .features,
    .download,
    .articles,
    .faq {
        padding: 60px 0;
    }

    .features-grid,
    .download-grid,
    .articles-grid {
        grid-template-columns: 1fr;
    }

    .footer-content {
        grid-template-columns: 1fr;
        gap: 40px;
    }

    .footer-links {
        grid-template-columns: 1fr 1fr;
    }

    .contact-grid {
        grid-template-columns: 1fr;
    }
}

@media (max-width: 480px) {
    .container {
        padding: 0 16px;
    }

    .hero-logo {
        width: 140px;
    }

    .hero-title {
        font-size: 1.75rem;
    }

    .hero-buttons {
        flex-direction: column;
    }

    .hero-buttons .btn {
        width: 100%;
    }

    .footer-links {
        grid-template-columns: 1fr;
    }
}

/* ===== Animations ===== */
@keyframes fadeInUp {
    from {
        opacity: 0;
        transform: translateY(30px);
    }
    to {
        opacity: 1;
        transform: translateY(0);
    }
}

.hero-content {
    animation: fadeInUp 0.8s ease-out;
}

.feature-card:nth-child(1) { animation-delay: 0.1s; }
.feature-card:nth-child(2) { animation-delay: 0.2s; }
.feature-card:nth-child(3) { animation-delay: 0.3s; }
.feature-card:nth-child(4) { animation-delay: 0.4s; }