/* 
  易翻译官网 - 高效、极简、SEO友好的静态CSS
*/
:root {
    --primary-color: #0d6efd;
    --primary-hover: #0b5ed7;
    --secondary-color: #6c757d;
    --secondary-hover: #5c636a;
    --text-main: #212529;
    --text-muted: #6c757d;
    --bg-main: #ffffff;
    --bg-light: #f8f9fa;
    --border-color: #dee2e6;
    --font-family: -apple-system, BlinkMacSystemFont, "Segoe UI", Roboto, "Helvetica Neue", Arial, "Noto Sans", "Liberation Sans", sans-serif;
    --border-radius: 8px;
    --transition: all 0.3s ease-in-out;
}

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

body {
    font-family: var(--font-family);
    color: var(--text-main);
    line-height: 1.6;
    background-color: var(--bg-main);
    font-size: 16px;
}

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

a:hover {
    color: var(--primary-hover);
}

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

/* Typography */
h1, h2, h3, h4 {
    margin-bottom: 0.5em;
    font-weight: 700;
    line-height: 1.2;
}

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

/* Header & Nav */
.header {
    border-bottom: 1px solid var(--border-color);
    background-color: var(--bg-main);
    position: sticky;
    top: 0;
    z-index: 1000;
}

.nav-container {
    display: flex;
    justify-content: space-between;
    align-items: center;
    height: 70px;
}

.logo h1 {
    font-size: 24px;
    color: var(--primary-color);
    margin: 0;
}

.nav-links a {
    margin-left: 20px;
    color: var(--text-main);
    font-weight: 500;
}

.nav-links a.active, .nav-links a:hover {
    color: var(--primary-color);
}

.btn-download-nav {
    background-color: var(--primary-color);
    color: #fff !important;
    padding: 8px 16px;
    border-radius: var(--border-radius);
}

.btn-download-nav:hover {
    background-color: var(--primary-hover);
    color: #fff !important;
}

/* Buttons */
.btn {
    display: inline-block;
    padding: 12px 24px;
    font-size: 16px;
    font-weight: 600;
    text-align: center;
    border-radius: var(--border-radius);
    cursor: pointer;
    border: none;
}

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

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

.btn-secondary {
    background-color: var(--bg-light);
    color: var(--text-main);
    border: 1px solid var(--border-color);
}

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

/* Utility */
.bg-light {
    background-color: var(--bg-light);
}

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

/* Hero Section */
.hero {
    padding: 80px 0;
    background: linear-gradient(135deg, #f8f9fa 0%, #e9ecef 100%);
}

.hero-content {
    display: flex;
    align-items: center;
    gap: 40px;
}

.hero-text {
    flex: 1;
}

.hero-text h2 {
    font-size: 40px;
    color: var(--text-main);
    margin-bottom: 20px;
}

.hero-features {
    list-style: none;
    margin-bottom: 30px;
}

.hero-features li {
    font-size: 18px;
    margin-bottom: 10px;
    color: var(--text-main);
}

.hero-buttons {
    display: flex;
    gap: 15px;
}

.hero-image {
    flex: 1;
    display: flex;
    justify-content: center;
}

.mockup {
    width: 100%;
    max-width: 500px;
    height: 350px;
    background-color: #fff;
    border: 2px solid var(--border-color);
    border-radius: 12px;
    box-shadow: 0 10px 30px rgba(0,0,0,0.1);
    display: flex;
    align-items: center;
    justify-content: center;
    color: var(--text-muted);
    font-size: 20px;
    font-weight: bold;
}

/* Features */
.features {
    padding: 80px 0;
}

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

.section-title h2 {
    font-size: 32px;
}

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

.feature-card {
    background-color: #fff;
    padding: 30px;
    border-radius: var(--border-radius);
    border: 1px solid var(--border-color);
    box-shadow: 0 4px 6px rgba(0,0,0,0.05);
    transition: var(--transition);
}

.feature-card:hover {
    transform: translateY(-5px);
    box-shadow: 0 10px 20px rgba(0,0,0,0.1);
}

.feature-card h3 {
    font-size: 22px;
    margin-bottom: 15px;
    color: var(--primary-color);
}

/* SEO Content Area */
.seo-content {
    padding: 60px 0;
}

.seo-content h2, .seo-content h3 {
    margin-top: 30px;
    margin-bottom: 15px;
}

/* Download Page Specifics */
.download-page {
    padding-bottom: 60px;
}

.download-hero {
    padding: 60px 0;
    background: #e9ecef;
    margin-bottom: 40px;
}

.download-hero h1 {
    font-size: 36px;
    margin-bottom: 15px;
}

.download-options {
    display: flex;
    flex-wrap: wrap;
    gap: 30px;
    justify-content: center;
}

.download-card {
    flex: 1;
    min-width: 300px;
    max-width: 350px;
    background: #fff;
    border: 1px solid var(--border-color);
    border-radius: var(--border-radius);
    padding: 40px 30px;
    text-align: center;
    box-shadow: 0 4px 15px rgba(0,0,0,0.05);
}

.os-icon {
    font-size: 24px;
    font-weight: bold;
    margin-bottom: 20px;
    color: var(--primary-color);
}

.download-card h2 {
    font-size: 24px;
    margin-bottom: 15px;
}

.download-card p {
    min-height: 80px;
}

.download-card .btn {
    width: 100%;
    margin-bottom: 15px;
}

.version-info {
    display: block;
    font-size: 13px;
    color: var(--text-muted);
}

.mobile-dl-buttons {
    display: flex;
    flex-direction: column;
    gap: 10px;
}

.install-guide {
    margin-top: 60px;
    padding: 60px 0;
}

.guide-steps {
    margin-left: 20px;
    margin-bottom: 40px;
}

.guide-steps li {
    margin-bottom: 15px;
    color: var(--text-main);
}

.faq h4 {
    margin-top: 20px;
    color: var(--primary-color);
}

/* Footer */
.footer {
    background-color: #212529;
    color: #f8f9fa;
    padding: 60px 0 20px;
}

.footer-content {
    display: flex;
    flex-wrap: wrap;
    gap: 40px;
    margin-bottom: 40px;
}

.footer-col {
    flex: 1;
    min-width: 250px;
}

.footer-col h4 {
    color: #fff;
    font-size: 18px;
    margin-bottom: 20px;
}

.footer-col p {
    color: #adb5bd;
}

.footer-col ul {
    list-style: none;
}

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

.footer-col ul li a {
    color: #adb5bd;
}

.footer-col ul li a:hover {
    color: #fff;
}

.footer-bottom {
    text-align: center;
    border-top: 1px solid #343a40;
    padding-top: 20px;
    color: #adb5bd;
    font-size: 14px;
}

/* Responsive */
@media (max-width: 768px) {
    .hero-content {
        flex-direction: column;
        text-align: center;
    }
    .hero-buttons {
        justify-content: center;
    }
    .nav-container {
        flex-direction: column;
        height: auto;
        padding: 15px;
    }
    .nav-links {
        margin-top: 15px;
        display: flex;
        flex-wrap: wrap;
        justify-content: center;
        gap: 10px;
    }
    .nav-links a {
        margin-left: 0;
    }
}