:root {
    --ds-bg: #f9fafe; /* 浅色背景，类似 DeepSeek 官网 */
    --ds-primary: #4d6bfe; /* DeepSeek 蓝 */
    --youdao-red: #E60012; /* 有道红 */
    --text-main: #1f2329;
    --text-sub: #646a73;
    --border-color: #e2e6eb;
    --card-bg: #ffffff;
    --shadow: 0 4px 12px rgba(0, 0, 0, 0.05);
    --radius-lg: 16px;
    --radius-md: 8px;
}

* {
    margin: 0;
    padding: 0;
    box-sizing: border-box;
    font-family: -apple-system, BlinkMacSystemFont, "Segoe UI", Roboto, "Helvetica Neue", Arial, sans-serif;
}

body {
    background-color: var(--ds-bg);
    color: var(--text-main);
    height: 100vh;
    display: flex;
    flex-direction: column;
}

.app-container {
    display: flex;
    flex-direction: column;
    height: 100%;
    max-width: 1400px;
    margin: 0 auto;
    width: 100%;
}

/* Header */
.ds-header {
    display: flex;
    justify-content: space-between;
    align-items: center;
    padding: 20px 40px;
    height: 80px;
}

.ds-logo {
    display: flex;
    align-items: center;
    gap: 12px;
    font-size: 20px;
    font-weight: 700;
}

.logo-icon {
    background: var(--youdao-red);
    color: white;
    padding: 4px 8px;
    border-radius: 6px;
    font-size: 16px;
    display: flex;
    gap: 2px;
}

.logo-text {
    color: var(--text-main);
    letter-spacing: -0.5px;
}

.ds-nav {
    display: flex;
    align-items: center;
    gap: 32px;
}

.ds-nav a {
    text-decoration: none;
    color: var(--text-sub);
    font-size: 15px;
    font-weight: 500;
    transition: color 0.2s;
}

.ds-nav a:hover, .ds-nav a.active {
    color: var(--youdao-red);
}

.login-btn {
    background: var(--text-main);
    color: white !important;
    padding: 8px 20px;
    border-radius: 20px;
    transition: opacity 0.2s;
}

.login-btn:hover {
    opacity: 0.9;
}

/* Main Content */
.ds-main {
    flex: 1;
    display: flex;
    flex-direction: column; /* Ensure column direction */
    align-items: center;    /* Horizontal center */
    padding: 0 20px;
    margin-top: 20px;       /* Small top margin */
    justify-content: flex-start; /* Align to top, not center */
}

.hero-content {
    width: 100%;
    max-width: 900px;
    display: flex;
    flex-direction: column;
    align-items: center;
    gap: 40px;
    margin-top: 40px; /* Add some spacing from header */
    transform: none;  /* Remove translation hack */
}

.brand-hero {
    text-align: center;
    margin-bottom: 10px;
}

/* Hero Download Module */
.hero-download-module {
    display: flex;
    align-items: center;
    justify-content: center;
    gap: 10px;
    margin-bottom: 30px;
    background: rgba(255, 255, 255, 0.6);
    padding: 8px 16px;
    border-radius: 30px;
    border: 1px solid rgba(0,0,0,0.05);
}

.dl-label {
    font-size: 13px;
    color: var(--text-sub);
    margin-right: 4px;
}

.dl-btn {
    text-decoration: none;
    display: flex;
    align-items: center;
    gap: 6px;
    padding: 6px 14px;
    border-radius: 20px;
    font-size: 13px;
    font-weight: 500;
    transition: all 0.2s;
    background: white;
    border: 1px solid var(--border-color);
    color: var(--text-main);
}

.dl-btn:hover {
    background: #f0f0f5;
    transform: translateY(-1px);
    border-color: #d0d0d5;
}

.dl-btn.primary {
    background: rgba(230, 0, 18, 0.1);
    color: var(--youdao-red);
    border-color: rgba(230, 0, 18, 0.2);
}

.dl-btn.primary:hover {
    background: rgba(230, 0, 18, 0.15);
}

.brand-hero h1 {
    font-size: 48px;
    font-weight: 800;
    margin-bottom: 12px;
    background: linear-gradient(120deg, var(--youdao-red), #ff4d4f);
    -webkit-background-clip: text;
    -webkit-text-fill-color: transparent;
}

.brand-hero .subtitle {
    font-size: 18px;
    color: var(--text-sub);
}

/* Translation Interface (Chat-like) */
.trans-interface {
    width: 100%;
    background: var(--card-bg);
    border-radius: var(--radius-lg);
    box-shadow: 0 8px 30px rgba(0, 0, 0, 0.08);
    border: 1px solid rgba(0,0,0,0.03);
    padding: 20px;
    transition: transform 0.3s ease, box-shadow 0.3s ease;
}

.trans-interface:focus-within {
    box-shadow: 0 12px 40px rgba(230, 0, 18, 0.15);
    border-color: rgba(230, 0, 18, 0.2);
}

.trans-input-area {
    display: flex;
    flex-direction: column;
    gap: 16px;
}

.lang-controls {
    display: flex;
    align-items: center;
    gap: 16px;
    padding-bottom: 12px;
    border-bottom: 1px solid var(--border-color);
}

.ds-select {
    border: none;
    background: transparent;
    font-size: 14px;
    font-weight: 600;
    color: var(--text-main);
    cursor: pointer;
    outline: none;
    padding: 4px 8px;
    border-radius: 4px;
}

.ds-select:hover {
    background: #f5f5f5;
}

.swap-icon {
    color: var(--text-sub);
    font-size: 14px;
    cursor: pointer;
}

textarea {
    width: 100%;
    min-height: 120px;
    border: none;
    resize: none;
    font-size: 18px;
    line-height: 1.6;
    color: var(--text-main);
    outline: none;
    background: transparent;
}

textarea::placeholder {
    color: #ccc;
}

.input-actions {
    display: flex;
    justify-content: flex-end;
    align-items: center;
    gap: 12px;
}

.ds-icon-btn {
    width: 36px;
    height: 36px;
    border: none;
    background: #f2f3f5;
    border-radius: 50%;
    color: var(--text-sub);
    cursor: pointer;
    transition: all 0.2s;
    display: flex;
    align-items: center;
    justify-content: center;
}

.ds-icon-btn:hover {
    background: #e4e6eb;
    color: var(--text-main);
}

.ds-send-btn {
    width: 40px;
    height: 40px;
    border: none;
    background: var(--youdao-red);
    color: white;
    border-radius: 12px;
    cursor: pointer;
    display: flex;
    align-items: center;
    justify-content: center;
    transition: transform 0.2s;
}

.ds-send-btn:hover {
    transform: scale(1.05);
    background: #d10010;
}

/* Feature Cards */
.feature-cards {
    display: grid;
    grid-template-columns: repeat(4, 1fr);
    gap: 16px;
    width: 100%;
}

.card {
    background: white;
    padding: 20px;
    border-radius: var(--radius-md);
    border: 1px solid var(--border-color);
    text-align: center;
    transition: all 0.3s;
    cursor: default;
}

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

.card i {
    font-size: 24px;
    color: var(--youdao-red);
    margin-bottom: 12px;
    opacity: 0.8;
}

.card h3 {
    font-size: 15px;
    margin-bottom: 6px;
    color: var(--text-main);
}

.card p {
    font-size: 12px;
    color: var(--text-sub);
    line-height: 1.4;
}

/* Footer */
.ds-footer {
    text-align: center;
    padding: 30px;
    color: var(--text-sub);
    font-size: 13px;
    display: flex;
    justify-content: center;
    gap: 20px;
    margin-top: auto;
    border-top: 1px solid var(--border-color);
}

.footer-links a {
    color: var(--text-sub);
    text-decoration: none;
    margin-left: 20px;
}

.footer-links a:hover {
    color: var(--youdao-red);
}

/* =========================================
   New Sections Styling - Centered & Stacked
   ========================================= */

.content-sections {
    width: 100%;
    margin-top: 40px;
    display: flex;
    flex-direction: column;
    gap: 80px;
    padding-bottom: 60px;
}

section {
    width: 100%;
}

.section-header {
    text-align: center;
    margin-bottom: 40px;
}

.section-header h2 {
    font-size: 32px;
    font-weight: 700;
    margin-bottom: 12px;
    color: var(--text-main);
}

.section-header p {
    font-size: 16px;
    color: var(--text-sub);
}

/* Detail Section Grid - Centered Items */
.feature-grid-lg {
    display: flex;
    flex-direction: column;
    gap: 24px;
    max-width: 800px; /* Limit width for better readability */
    margin: 0 auto;   /* Center the column */
}

.feature-item-lg {
    background: white;
    padding: 30px;
    border-radius: var(--radius-lg);
    border: 1px solid var(--border-color);
    display: flex;
    flex-direction: row; /* Icon left, text right */
    align-items: center;    
    text-align: left;     
    gap: 30px;
    transition: all 0.3s ease;
}

.feature-item-lg:hover {
    box-shadow: var(--shadow);
    transform: translateY(-2px);
    border-color: rgba(230, 0, 18, 0.1);
}

.feature-item-lg .f-icon {
    width: 60px;
    height: 60px;
    background: rgba(230, 0, 18, 0.05);
    border-radius: 16px;
    display: flex;
    align-items: center;
    justify-content: center;
    font-size: 24px;
    color: var(--youdao-red);
    flex-shrink: 0;
}

.feature-item-lg .f-content {
    flex: 1;
}

.feature-item-lg .f-content h3 {
    font-size: 20px;
    margin-bottom: 8px;
    color: var(--text-main);
}

.feature-item-lg .f-content p {
    font-size: 14px;
    color: var(--text-sub);
    line-height: 1.6;
}

/* Ecosystem Section - Stacked (Left Module at Top) */
.ecosystem-section {
    background: white;
    border-radius: var(--radius-lg);
    border: 1px solid var(--border-color);
    overflow: hidden;
}

.eco-container {
    display: flex;
    flex-direction: column; /* Stack vertical */
    align-items: center;
    text-align: center;     /* Center text */
    padding: 60px;
    gap: 40px;
}

.eco-text {
    width: 100%;
    max-width: 800px;
}

.eco-text h2 {
    font-size: 32px;
    font-weight: 700;
    margin-bottom: 20px;
}

.eco-text p {
    color: var(--text-sub);
    margin-bottom: 30px;
    font-size: 16px;
}

.eco-list {
    list-style: none;
    display: flex;
    justify-content: center;
    gap: 30px;
    flex-wrap: wrap;
}

.eco-list li {
    margin-bottom: 0;
    display: flex;
    align-items: center;
    gap: 8px;
    color: var(--text-main);
    font-size: 15px;
}

.eco-list li i {
    color: var(--youdao-red);
}

.eco-visual {
    width: 100%;
    max-width: 800px;
    height: 300px;
    position: relative;
    background: #f9fafe;
    border-radius: var(--radius-lg);
    display: flex;
    justify-content: center;
    align-items: center;
}

.device-mockup {
    background: white;
    border: 1px solid var(--border-color);
    box-shadow: var(--shadow);
    border-radius: 12px;
    display: flex;
    align-items: center;
    justify-content: center;
    position: absolute;
    font-weight: 600;
    color: var(--text-sub);
}

.device-mockup.pc {
    width: 240px;
    height: 160px;
    z-index: 1;
    top: 50%;
    left: 50%;
    transform: translate(-60%, -60%);
}

.device-mockup.mobile {
    width: 100px;
    height: 180px;
    z-index: 2;
    top: 50%;
    left: 50%;
    transform: translate(40%, -30%);
    background: #fff;
}

/* Stats Section */
.stats-section {
    display: flex;
    justify-content: center;
    align-items: center;
    padding: 40px 0;
    background: linear-gradient(to right, rgba(230, 0, 18, 0.02), rgba(77, 107, 254, 0.02));
    border-radius: var(--radius-lg);
}

.stat-item {
    text-align: center;
    padding: 0 60px;
}

.stat-num {
    font-size: 48px;
    font-weight: 800;
    color: var(--youdao-red);
    margin-bottom: 8px;
}

.stat-desc {
    color: var(--text-sub);
    font-size: 14px;
    text-transform: uppercase;
    letter-spacing: 1px;
}

.stat-divider {
    width: 1px;
    height: 60px;
    background: var(--border-color);
}

/* Bottom CTA */
.bottom-cta {
    text-align: center;
    padding: 80px 0 20px;
}

.bottom-cta h2 {
    font-size: 36px;
    font-weight: 800;
    margin-bottom: 16px;
}

.bottom-cta p {
    color: var(--text-sub);
    font-size: 18px;
    margin-bottom: 40px;
}

.cta-buttons {
    display: flex;
    justify-content: center;
    gap: 20px;
    margin-bottom: 20px;
}

.btn-primary-lg, .btn-secondary-lg {
    padding: 16px 32px;
    border-radius: 30px;
    font-size: 16px;
    font-weight: 600;
    cursor: pointer;
    display: flex;
    align-items: center;
    gap: 10px;
    transition: all 0.2s;
}

.btn-primary-lg {
    background: var(--youdao-red);
    color: white;
    border: none;
    box-shadow: 0 4px 15px rgba(230, 0, 18, 0.3);
}

.btn-primary-lg:hover {
    background: #d10010;
    transform: translateY(-2px);
    box-shadow: 0 6px 20px rgba(230, 0, 18, 0.4);
}

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

.btn-secondary-lg:hover {
    border-color: var(--text-main);
    background: #f9f9f9;
}

.cta-note {
    font-size: 13px !important;
    opacity: 0.6;
}

/* =========================================
   Detail Page Styling
   ========================================= */

.detail-layout {
    flex-direction: column;
    justify-content: flex-start;
    padding-top: 40px;
    align-items: center;
}

.detail-hero {
    text-align: center;
    margin-bottom: 60px;
    max-width: 800px;
}

.detail-hero .icon-wrapper {
    width: 80px;
    height: 80px;
    background: rgba(230, 0, 18, 0.05);
    border-radius: 20px;
    display: flex;
    align-items: center;
    justify-content: center;
    font-size: 32px;
    color: var(--youdao-red);
    margin: 0 auto 24px;
}

.detail-hero h1 {
    font-size: 42px;
    font-weight: 800;
    margin-bottom: 16px;
    color: var(--text-main);
}

.detail-subtitle {
    font-size: 20px;
    color: var(--text-sub);
}

.detail-content {
    width: 100%;
    max-width: 800px;
    display: flex;
    flex-direction: column;
    gap: 40px;
    padding-bottom: 60px;
}

.info-block {
    background: white;
    padding: 40px;
    border-radius: var(--radius-lg);
    border: 1px solid var(--border-color);
}

.info-block h2 {
    font-size: 24px;
    margin-bottom: 20px;
    display: flex;
    align-items: center;
    gap: 12px;
}

.info-block h2 i {
    color: var(--youdao-red);
    font-size: 20px;
}

.info-block p {
    font-size: 16px;
    line-height: 1.8;
    color: var(--text-sub);
}

.detail-cta {
    text-align: center;
    margin-top: 20px;
    padding: 40px;
    background: linear-gradient(to bottom, transparent, rgba(230, 0, 18, 0.02));
    border-radius: var(--radius-lg);
}

.detail-cta h3 {
    font-size: 24px;
    margin-bottom: 24px;
}

.detail-cta button {
    margin: 0 auto;
}
    .feature-cards {
        grid-template-columns: 1fr 1fr;
    }
    
    .feature-grid-lg {
        grid-template-columns: 1fr;
    }
    
    .eco-container {
        flex-direction: column;
        padding: 30px;
        text-align: center;
    }
    
    .eco-list li {
        justify-content: center;
    }
    
    .eco-visual {
        width: 100%;
    }
    
    .stats-section {
        flex-direction: column;
        gap: 30px;
    }
    
    .stat-divider {
        width: 60px;
        height: 1px;
    }
    
    .cta-buttons {
        flex-direction: column;
    }
    
    .brand-hero h1 {
        font-size: 32px;
    }
    
    .ds-nav {
        display: none; /* Mobile Menu to be implemented */
    }
}