/* Global Styles */
:root {
    --primary-color: #e84339;
    --primary-hover: #d3362d;
    --bg-color: #ffffff;
    --light-bg: #f8faff;
    --surface-color: #ffffff;
    --text-primary: #1f2937;
    --text-secondary: #6b7280;
    --border-color: #e5e7eb;
    --shadow-sm: 0 1px 2px 0 rgba(0, 0, 0, 0.05);
    --shadow-md: 0 4px 6px -1px rgba(0, 0, 0, 0.1), 0 2px 4px -1px rgba(0, 0, 0, 0.06);
    --shadow-lg: 0 10px 25px -5px rgba(0, 0, 0, 0.05), 0 8px 10px -6px rgba(0, 0, 0, 0.05);
}

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

html {
    scroll-behavior: smooth;
}

body {
    font-family: -apple-system, BlinkMacSystemFont, "Segoe UI", Roboto, "Helvetica Neue", Arial, "PingFang SC", "Microsoft YaHei", sans-serif;
    background-color: var(--bg-color);
    color: var(--text-primary);
    line-height: 1.6;
    overflow-x: hidden;
}

.container {
    max-width: 1200px;
    margin: 0 auto;
    padding: 0 24px;
}

a {
    text-decoration: none;
    color: inherit;
    transition: all 0.2s ease;
}

ul {
    list-style: none;
}

.flex { display: flex; }
.flex-1 { flex: 1; }
.justify-between { justify-content: space-between; }
.justify-center { justify-content: center; }
.align-center { align-items: center; }
.text-center { text-align: center; }
.gap-10 { gap: 10px; }
.gap-20 { gap: 20px; }
.gap-40 { gap: 40px; }
.mt-20 { margin-top: 20px; }

/* Buttons */
.btn {
    display: inline-flex;
    align-items: center;
    justify-content: center;
    font-weight: 600;
    border-radius: 8px;
    cursor: pointer;
    transition: all 0.2s ease;
    border: none;
}

.btn-sm { padding: 8px 16px; font-size: 14px; }
.btn-md { padding: 10px 24px; font-size: 15px; }
.btn-lg { padding: 16px 40px; font-size: 18px; border-radius: 50px; }

.btn-primary {
    background-color: var(--primary-color);
    color: white;
}
.btn-primary:hover {
    background-color: var(--primary-hover);
    transform: translateY(-2px);
    box-shadow: 0 8px 20px rgba(232, 67, 57, 0.3);
}

.btn-outline {
    background-color: transparent;
    border: 2px solid var(--border-color);
    color: var(--text-primary);
}
.btn-outline:hover {
    border-color: var(--primary-color);
    color: var(--primary-color);
}

.btn-white {
    background-color: white;
    color: var(--primary-color);
}
.btn-white:hover {
    transform: translateY(-2px);
    box-shadow: 0 8px 20px rgba(255, 255, 255, 0.3);
}

.btn-outline-white {
    background-color: transparent;
    border: 2px solid white;
    color: white;
}
.btn-outline-white:hover {
    background-color: white;
    color: var(--primary-color);
}

/* Header */
.header {
    height: 80px;
    background-color: rgba(255, 255, 255, 0.95);
    backdrop-filter: blur(10px);
    border-bottom: 1px solid var(--border-color);
    position: sticky;
    top: 0;
    z-index: 1000;
}

.logo .brand-box {
    margin-left: 12px;
}

.brand-name {
    display: block;
    font-size: 20px;
    font-weight: 700;
    color: var(--text-primary);
    line-height: 1.2;
}

.brand-tagline {
    font-size: 12px;
    color: var(--text-secondary);
    letter-spacing: 1px;
}

.nav ul li a {
    font-size: 16px;
    font-weight: 500;
    color: var(--text-primary);
    padding: 0 20px;
}

.nav ul li a:hover {
    color: var(--primary-color);
}

/* Hero Section */
.hero {
    padding: 80px 0 100px;
    background: radial-gradient(circle at top right, #fff5f5 0%, #ffffff 50%);
}

.hero-title {
    font-size: 56px;
    font-weight: 800;
    margin-bottom: 24px;
    color: #111827;
    letter-spacing: -2px;
}

.hero-subtitle {
    font-size: 22px;
    color: var(--text-secondary);
    max-width: 700px;
    margin: 0 auto 48px;
}

.hero-actions {
    display: flex;
    justify-content: center;
    gap: 20px;
    margin-bottom: 80px;
}

/* Translate Panel */
.translate-panel {
    background: white;
    border-radius: 24px;
    border: 1px solid var(--border-color);
    box-shadow: 0 25px 50px -12px rgba(0, 0, 0, 0.1);
    overflow: hidden;
    max-width: 1000px;
    margin: 0 auto;
}

.panel-header {
    padding: 16px 24px;
    background-color: #f9fafb;
    border-bottom: 1px solid #f1f5f9;
}

.chip {
    padding: 8px 18px;
    border-radius: 50px;
    background-color: #f3f4f6;
    font-size: 14px;
    font-weight: 500;
    color: #4b5563;
    cursor: pointer;
}

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

.chip.secondary {
    background-color: #ecfdf5;
    color: #059669;
    border: 1px solid #d1fae5;
}

.panel-body {
    min-height: 320px;
}

.source-area, .target-area {
    flex: 1;
    padding: 32px;
    text-align: left;
}

.source-area {
    border-right: 1px solid #f1f5f9;
}

textarea {
    width: 100%;
    height: 100%;
    border: none;
    resize: none;
    outline: none;
    font-size: 18px;
    color: var(--text-primary);
    background: transparent;
    font-family: inherit;
    line-height: 1.6;
}

textarea::placeholder {
    color: #9ca3af;
}

.panel-footer {
    padding: 16px 24px;
    background-color: #ffffff;
    border-top: 1px solid #f1f5f9;
}

.tool-btn {
    font-size: 14px;
    color: #6b7280;
    padding: 6px 12px;
    border-radius: 6px;
    cursor: pointer;
    transition: all 0.2s;
}

.tool-btn:hover {
    background-color: #f3f4f6;
    color: var(--primary-color);
}

/* Keywords Bar */
.keywords-bar {
    padding: 24px 0;
    border-top: 1px solid var(--border-color);
    border-bottom: 1px solid var(--border-color);
}

.keyword-item {
    font-size: 14px;
    color: var(--text-secondary);
}

.keyword-item strong {
    color: var(--text-primary);
    margin: 0 5px;
}

/* Sections */
.section {
    padding: 100px 0;
}

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

.section-header {
    margin-bottom: 80px;
    text-align: center;
}

.section-title {
    font-size: 40px;
    font-weight: 800;
    margin-bottom: 20px;
    color: #111827;
}

.section-subtitle {
    font-size: 18px;
    color: var(--text-secondary);
    max-width: 600px;
    margin: 0 auto;
}

.grid {
    display: grid;
    gap: 32px;
}

.grid-3 { grid-template-columns: repeat(3, 1fr); }

/* Cards */
.feature-card {
    background: white;
    border: 1px solid var(--border-color);
    border-radius: 20px;
    padding: 40px;
    transition: all 0.4s cubic-bezier(0.175, 0.885, 0.32, 1.275);
    position: relative;
    overflow: hidden;
}

.feature-card:hover {
    transform: translateY(-12px);
    box-shadow: 0 30px 60px -12px rgba(0, 0, 0, 0.1);
    border-color: rgba(232, 67, 57, 0.2);
}

.feature-card .badge {
    position: absolute;
    top: 20px;
    right: 20px;
    background-color: #fef2f2;
    color: var(--primary-color);
    padding: 4px 12px;
    border-radius: 6px;
    font-size: 12px;
    font-weight: 700;
}

.card-title {
    font-size: 24px;
    margin-bottom: 16px;
    color: #111827;
}

.card-text {
    color: var(--text-secondary);
    font-size: 16px;
}

/* Scenarios */
.scenario-item {
    margin-bottom: 32px;
}

.scenario-item h4 {
    font-size: 20px;
    margin-bottom: 12px;
    color: #111827;
}

.image-placeholder {
    background: linear-gradient(135deg, #f3f4f6 0%, #e5e7eb 100%);
    border-radius: 24px;
    aspect-ratio: 16/10;
    display: flex;
    align-center: center;
    justify-content: center;
    border: 1px solid var(--border-color);
}

.placeholder-text {
    color: #9ca3af;
    font-weight: 500;
}

/* FAQ */
.faq-list {
    max-width: 800px;
    margin: 40px auto 0;
}

.faq-item {
    background: white;
    border: 1px solid var(--border-color);
    border-radius: 16px;
    margin-bottom: 16px;
    padding: 24px;
}

.faq-question {
    font-weight: 700;
    font-size: 18px;
    margin-bottom: 12px;
    color: #111827;
}

.faq-answer {
    color: var(--text-secondary);
    font-size: 16px;
}

/* Download Section */
.download-section {
    background: linear-gradient(135deg, #e84339 0%, #c12a21 100%);
    padding: 100px 0;
    color: white;
    border-radius: 40px 40px 0 0;
}

.download-actions {
    margin: 48px 0 32px;
}

.trust-badges {
    font-size: 14px;
    opacity: 0.9;
}

.version-info {
    font-size: 14px;
    opacity: 0.7;
}

/* Footer */
.footer-bottom {
    padding: 60px 0;
    background: #111827;
    color: #9ca3af;
    font-size: 14px;
}

.footer-info p {
    margin-bottom: 10px;
}

.legal-links a {
    color: #9ca3af;
    margin: 0 8px;
}

.legal-links a:hover {
    color: white;
}

.footer-keywords a {
    color: white;
    font-weight: 500;
}

/* Responsive */
@media (max-width: 1024px) {
    .hero-title { font-size: 48px; }
    .grid-3 { grid-template-columns: repeat(2, 1fr); }
}

@media (max-width: 768px) {
    .header .nav, .header-cta { display: none; }
    .hero-title { font-size: 36px; letter-spacing: -1px; }
    .hero-subtitle { font-size: 18px; }
    .grid-3 { grid-template-columns: 1fr; }
    .scenario-content { flex-direction: column; }
    .hero-actions { flex-direction: column; }
    .panel-body { flex-direction: column; }
    .source-area { border-right: none; border-bottom: 1px solid #f1f5f9; }
    .translate-panel { margin: 0; border-radius: 16px; }
    .download-actions { flex-direction: column; align-items: center; }
}