/* ========================================
   Dongbau Technology — Brand Styles
   Color: Verdant Green + Health + AI
   Style: Minimal, Clean, Modern
   ======================================== */

:root {
    /* Brand Colors - Verdant Green System */
    --color-primary: #2D9B6E;
    --color-primary-light: #3DB87F;
    --color-primary-dark: #1F7A54;
    --color-primary-50: #EDFAF3;
    --color-primary-100: #D0F0E0;
    --color-primary-200: #A3E4C2;
    --color-primary-300: #6DD3A2;
    --color-primary-400: #3DB87F;
    --color-primary-500: #2D9B6E;
    --color-primary-600: #1F7A54;
    --color-primary-700: #175E40;
    --color-primary-800: #10452F;
    --color-primary-900: #0A2D1F;

    /* Accent - AI Blue */
    --color-accent: #0EA5E9;
    --color-accent-light: #38BDF8;
    --color-accent-50: #F0F9FF;

    /* Neutrals */
    --color-bg: #FAFDFB;
    --color-bg-alt: #F0F7F3;
    --color-bg-dark: #0A2D1F;
    --color-surface: #FFFFFF;
    --color-text: #1A2E23;
    --color-text-secondary: #4A6B58;
    --color-text-tertiary: #7A9B8A;
    --color-border: #D0E4D8;
    --color-border-light: #E8F2EC;

    /* Gradients */
    --gradient-hero: linear-gradient(135deg, #0A2D1F 0%, #14523A 40%, #1F7A54 100%);
    --gradient-primary: linear-gradient(135deg, var(--color-primary) 0%, var(--color-primary-light) 100%);
    --gradient-accent: linear-gradient(135deg, var(--color-primary) 0%, var(--color-accent) 100%);
    --gradient-card: linear-gradient(180deg, var(--color-surface) 0%, var(--color-primary-50) 100%);

    /* Shadows */
    --shadow-sm: 0 1px 3px rgba(10, 45, 31, 0.06);
    --shadow-md: 0 4px 16px rgba(10, 45, 31, 0.08);
    --shadow-lg: 0 8px 32px rgba(10, 45, 31, 0.12);
    --shadow-xl: 0 16px 48px rgba(10, 45, 31, 0.16);

    /* Typography */
    --font-main: 'Noto Sans SC', -apple-system, BlinkMacSystemFont, 'Segoe UI', sans-serif;
    --font-mono: 'SF Mono', 'Fira Code', monospace;

    /* Spacing */
    --section-padding: 100px 0;
    --container-max: 1200px;

    /* Transitions */
    --transition-fast: 0.2s ease;
    --transition-base: 0.3s ease;
    --transition-slow: 0.5s ease;

    /* Border Radius */
    --radius-sm: 8px;
    --radius-md: 12px;
    --radius-lg: 20px;
    --radius-xl: 28px;
}

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

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

body {
    font-family: var(--font-main);
    color: var(--color-text);
    background-color: var(--color-bg);
    line-height: 1.7;
    -webkit-font-smoothing: antialiased;
    -moz-osx-font-smoothing: grayscale;
    overflow-x: hidden;
}

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

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

/* Container */
.container {
    max-width: var(--container-max);
    margin: 0 auto;
    padding: 0 24px;
}

/* ========================================
   Navigation
   ======================================== */
.navbar {
    position: fixed;
    top: 0;
    left: 0;
    right: 0;
    z-index: 1000;
    padding: 16px 0;
    transition: all var(--transition-base);
    background: transparent;
}

.navbar.scrolled {
    background: rgba(255, 255, 255, 0.92);
    backdrop-filter: blur(20px);
    -webkit-backdrop-filter: blur(20px);
    border-bottom: 1px solid var(--color-border-light);
    padding: 12px 0;
}

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

.logo {
    display: flex;
    align-items: center;
    gap: 10px;
    font-weight: 700;
    font-size: 1.25rem;
    color: #fff;
    transition: color var(--transition-fast);
}

.navbar.scrolled .logo {
    color: var(--color-text);
}

.logo-img {
    width: 32px;
    height: 32px;
    border-radius: 6px;
    object-fit: cover;
}

.logo-icon {
    font-size: 1.5rem;
    color: var(--color-primary-light);
}

.nav-links {
    display: flex;
    gap: 36px;
}

.nav-links a {
    font-size: 0.9rem;
    font-weight: 400;
    color: rgba(255, 255, 255, 0.75);
    letter-spacing: 0.5px;
    transition: color var(--transition-fast);
    position: relative;
}

.nav-links a::after {
    content: '';
    position: absolute;
    bottom: -4px;
    left: 0;
    width: 0;
    height: 2px;
    background: var(--color-primary-light);
    transition: width var(--transition-base);
}

.nav-links a:hover::after {
    width: 100%;
}

.nav-links a:hover {
    color: #fff;
}

.navbar.scrolled .nav-links a {
    color: var(--color-text-secondary);
}

.navbar.scrolled .nav-links a:hover {
    color: var(--color-primary);
}

.navbar.scrolled .nav-links a::after {
    background: var(--color-primary);
}

.nav-toggle {
    display: none;
    flex-direction: column;
    gap: 5px;
    background: none;
    border: none;
    cursor: pointer;
    padding: 4px;
}

.nav-toggle span {
    display: block;
    width: 24px;
    height: 2px;
    background: #fff;
    border-radius: 2px;
    transition: all var(--transition-base);
}

.navbar.scrolled .nav-toggle span {
    background: var(--color-text);
}

/* ========================================
   Hero
   ======================================== */
.hero {
    position: relative;
    min-height: 100vh;
    display: flex;
    align-items: center;
    justify-content: center;
    overflow: hidden;
}

.hero-bg {
    position: absolute;
    inset: 0;
    background: var(--gradient-hero);
    z-index: 0;
}

.hero-bg::before {
    content: '';
    position: absolute;
    inset: 0;
    background:
        radial-gradient(ellipse 60% 50% at 20% 80%, rgba(45, 155, 110, 0.3) 0%, transparent 70%),
        radial-gradient(ellipse 50% 40% at 80% 20%, rgba(14, 165, 233, 0.15) 0%, transparent 70%),
        radial-gradient(ellipse 80% 60% at 50% 50%, rgba(61, 184, 127, 0.1) 0%, transparent 80%);
}

.hero-bg::after {
    content: '';
    position: absolute;
    inset: 0;
    background-image:
        radial-gradient(rgba(255, 255, 255, 0.03) 1px, transparent 1px);
    background-size: 40px 40px;
}

.hero-content {
    position: relative;
    z-index: 1;
    text-align: center;
    color: #fff;
    padding: 120px 0 80px;
}

.hero-title {
    font-size: clamp(2.5rem, 6vw, 5rem);
    font-weight: 700;
    letter-spacing: -1px;
    margin-bottom: 20px;
    line-height: 1.2;
}

.title-accent {
    background: linear-gradient(135deg, var(--color-primary-light), var(--color-accent-light));
    -webkit-background-clip: text;
    -webkit-text-fill-color: transparent;
    background-clip: text;
}

.hero-subtitle {
    font-size: clamp(1.1rem, 2.5vw, 1.5rem);
    font-weight: 300;
    opacity: 0.9;
    margin-bottom: 16px;
    letter-spacing: 2px;
}

.hero-desc {
    font-size: 1rem;
    line-height: 1.8;
    opacity: 0.7;
    max-width: 560px;
    margin: 0 auto 40px;
}

.hero-actions {
    display: flex;
    gap: 16px;
    justify-content: center;
    flex-wrap: wrap;
}

.btn {
    display: inline-flex;
    align-items: center;
    justify-content: center;
    padding: 14px 36px;
    border-radius: var(--radius-xl);
    font-size: 0.95rem;
    font-weight: 500;
    letter-spacing: 0.5px;
    transition: all var(--transition-base);
    cursor: pointer;
    border: none;
}

.btn-primary {
    background: var(--gradient-accent);
    color: #fff;
    box-shadow: 0 4px 20px rgba(45, 155, 110, 0.35);
}

.btn-primary:hover {
    transform: translateY(-2px);
    box-shadow: 0 8px 30px rgba(45, 155, 110, 0.45);
}

.btn-outline {
    background: transparent;
    color: #fff;
    border: 1.5px solid rgba(255, 255, 255, 0.3);
}

.btn-outline:hover {
    border-color: rgba(255, 255, 255, 0.6);
    background: rgba(255, 255, 255, 0.08);
}

.hero-scroll {
    position: absolute;
    bottom: 40px;
    left: 50%;
    transform: translateX(-50%);
    z-index: 1;
    display: flex;
    flex-direction: column;
    align-items: center;
    gap: 8px;
    color: rgba(255, 255, 255, 0.5);
    font-size: 0.8rem;
    letter-spacing: 1px;
    animation: fadeInUp 1s ease 1.5s both;
}

.scroll-arrow {
    width: 20px;
    height: 20px;
    border-right: 2px solid rgba(255, 255, 255, 0.4);
    border-bottom: 2px solid rgba(255, 255, 255, 0.4);
    transform: rotate(45deg);
    animation: bounceDown 2s infinite;
}

@keyframes bounceDown {
    0%, 100% { transform: rotate(45deg) translateY(0); }
    50% { transform: rotate(45deg) translateY(6px); }
}

@keyframes fadeInUp {
    from { opacity: 0; transform: translateX(-50%) translateY(20px); }
    to { opacity: 1; transform: translateX(-50%) translateY(0); }
}

/* ========================================
   Section Common
   ======================================== */
.section {
    padding: var(--section-padding);
}

.section-header {
    text-align: center;
    margin-bottom: 64px;
}

.section-tag {
    display: inline-block;
    padding: 6px 16px;
    background: var(--color-primary-50);
    color: var(--color-primary);
    font-size: 0.75rem;
    font-weight: 500;
    letter-spacing: 2px;
    border-radius: var(--radius-xl);
    margin-bottom: 16px;
}

.section-title {
    font-size: clamp(1.8rem, 3.5vw, 2.8rem);
    font-weight: 700;
    color: var(--color-text);
    margin-bottom: 12px;
    letter-spacing: -0.5px;
}

.section-subtitle {
    font-size: 1.05rem;
    color: var(--color-text-tertiary);
    font-weight: 300;
}

/* ========================================
   About
   ======================================== */
.about {
    background: var(--color-surface);
}

.about-grid {
    display: grid;
    grid-template-columns: repeat(3, 1fr);
    gap: 32px;
    margin-bottom: 56px;
}

.about-card {
    padding: 40px 32px;
    background: var(--gradient-card);
    border: 1px solid var(--color-border-light);
    border-radius: var(--radius-lg);
    text-align: center;
    transition: all var(--transition-base);
}

.about-card:hover {
    transform: translateY(-4px);
    box-shadow: var(--shadow-lg);
    border-color: var(--color-primary-200);
}

.about-icon {
    width: 56px;
    height: 56px;
    margin: 0 auto 24px;
    color: var(--color-primary);
}

.about-card h3 {
    font-size: 1.25rem;
    font-weight: 600;
    margin-bottom: 12px;
    color: var(--color-text);
}

.about-card p {
    font-size: 0.92rem;
    color: var(--color-text-secondary);
    line-height: 1.75;
}

.about-quote {
    text-align: center;
    padding: 40px 20px;
}

.about-quote blockquote {
    font-size: clamp(1rem, 2vw, 1.3rem);
    color: var(--color-text-secondary);
    font-style: italic;
    font-weight: 300;
    position: relative;
    display: inline-block;
}

.about-quote blockquote::before {
    content: '"';
    position: absolute;
    top: -20px;
    left: -30px;
    font-size: 4rem;
    color: var(--color-primary-200);
    font-family: Georgia, serif;
    line-height: 1;
}

/* ========================================
   Vision
   ======================================== */
.vision {
    background: var(--color-bg-alt);
}

.vision-statement {
    max-width: 800px;
    margin: 0 auto;
}

.vision-lead {
    font-size: 1.3rem;
    font-weight: 300;
    color: var(--color-text-tertiary);
    margin-bottom: 48px;
    text-align: center;
}

.vision-items {
    display: flex;
    flex-direction: column;
    gap: 40px;
}

.vision-item {
    display: flex;
    gap: 32px;
    align-items: flex-start;
}

.vision-number {
    flex-shrink: 0;
    width: 56px;
    height: 56px;
    display: flex;
    align-items: center;
    justify-content: center;
    background: var(--gradient-accent);
    color: #fff;
    font-size: 1.1rem;
    font-weight: 700;
    border-radius: var(--radius-md);
    letter-spacing: 1px;
}

.vision-text h3 {
    font-size: 1.2rem;
    font-weight: 600;
    margin-bottom: 8px;
    color: var(--color-text);
}

.vision-text p {
    font-size: 0.95rem;
    color: var(--color-text-secondary);
    line-height: 1.75;
}

/* ========================================
   Direction
   ======================================== */
.direction {
    background: var(--color-surface);
}

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

.direction-card {
    padding: 40px 32px;
    background: var(--color-bg);
    border: 1px solid var(--color-border-light);
    border-radius: var(--radius-lg);
    transition: all var(--transition-base);
    position: relative;
    overflow: hidden;
}

.direction-card::before {
    content: '';
    position: absolute;
    top: 0;
    left: 0;
    right: 0;
    height: 3px;
    background: var(--gradient-accent);
    opacity: 0;
    transition: opacity var(--transition-base);
}

.direction-card:hover {
    transform: translateY(-4px);
    box-shadow: var(--shadow-lg);
}

.direction-card:hover::before {
    opacity: 1;
}

.direction-icon-wrap {
    width: 64px;
    height: 64px;
    margin-bottom: 20px;
    color: var(--color-primary);
}

.direction-tag {
    display: inline-block;
    padding: 4px 12px;
    background: var(--color-primary-50);
    color: var(--color-primary);
    font-size: 0.75rem;
    font-weight: 500;
    border-radius: var(--radius-xl);
    margin-bottom: 16px;
    letter-spacing: 1px;
}

.direction-card h3 {
    font-size: 1.3rem;
    font-weight: 600;
    margin-bottom: 12px;
    color: var(--color-text);
}

.direction-card > p {
    font-size: 0.92rem;
    color: var(--color-text-secondary);
    line-height: 1.75;
    margin-bottom: 20px;
}

.direction-features {
    list-style: none;
    display: grid;
    grid-template-columns: 1fr 1fr;
    gap: 8px;
}

.direction-features li {
    font-size: 0.85rem;
    color: var(--color-text-tertiary);
    padding-left: 20px;
    position: relative;
}

.direction-features li::before {
    content: '→';
    position: absolute;
    left: 0;
    color: var(--color-primary);
}

/* ========================================
   Roadmap / Timeline
   ======================================== */
.roadmap {
    background: var(--color-bg-alt);
}

.timeline {
    max-width: 700px;
    margin: 0 auto;
    position: relative;
    padding-left: 40px;
}

.timeline::before {
    content: '';
    position: absolute;
    left: 15px;
    top: 0;
    bottom: 0;
    width: 2px;
    background: var(--color-border);
}

.timeline-item {
    position: relative;
    padding-bottom: 48px;
}

.timeline-item:last-child {
    padding-bottom: 0;
}

.timeline-dot {
    position: absolute;
    left: -33px;
    top: 6px;
    width: 14px;
    height: 14px;
    border-radius: 50%;
    background: var(--color-primary);
    border: 3px solid var(--color-primary-100);
}

.timeline-dot.future {
    background: var(--color-accent);
    border-color: var(--color-accent-50);
}

.timeline-year {
    display: inline-block;
    padding: 4px 14px;
    background: var(--color-primary-50);
    color: var(--color-primary);
    font-size: 0.8rem;
    font-weight: 600;
    border-radius: var(--radius-xl);
    margin-bottom: 8px;
    letter-spacing: 1px;
}

.timeline-content h3 {
    font-size: 1.15rem;
    font-weight: 600;
    margin-bottom: 6px;
    color: var(--color-text);
}

.timeline-content p {
    font-size: 0.92rem;
    color: var(--color-text-secondary);
    line-height: 1.7;
}

/* ========================================
   Contact
   ======================================== */
.contact {
    background: var(--color-surface);
}

.contact-content {
    max-width: 600px;
    margin: 0 auto;
}

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

.contact-item {
    display: flex;
    align-items: center;
    gap: 20px;
    padding: 24px 32px;
    background: var(--color-bg);
    border: 1px solid var(--color-border-light);
    border-radius: var(--radius-lg);
    transition: all var(--transition-base);
}

.contact-item:hover {
    border-color: var(--color-primary-200);
    box-shadow: var(--shadow-md);
}

.contact-icon {
    width: 40px;
    height: 40px;
    color: var(--color-primary);
    flex-shrink: 0;
}

.contact-item h3 {
    font-size: 0.85rem;
    font-weight: 500;
    color: var(--color-text-tertiary);
    margin-bottom: 2px;
}

.contact-item p {
    font-size: 1rem;
    color: var(--color-text);
    font-weight: 500;
}

/* ========================================
   Footer
   ======================================== */
.footer {
    background: var(--color-bg-dark);
    color: rgba(255, 255, 255, 0.6);
    padding: 48px 0;
}

.footer-content {
    display: flex;
    align-items: center;
    justify-content: space-between;
    flex-wrap: wrap;
    gap: 16px;
}

.footer-brand {
    display: flex;
    align-items: center;
    gap: 8px;
    font-size: 0.9rem;
}

.footer-logo-img {
    width: 28px;
    height: 28px;
    border-radius: 6px;
    object-fit: cover;
}

.footer-brand .logo-icon {
    color: var(--color-primary-light);
}

.beian-row {
    margin-top: 4px;
}

.beian-row a {
    color: rgba(255, 255, 255, 0.5);
    font-size: 0.8rem;
    transition: color var(--transition-fast);
}

.beian-row a:hover {
    color: var(--color-primary-light);
}

.footer-links a {
    color: rgba(255, 255, 255, 0.5);
    font-size: 0.85rem;
    transition: color var(--transition-fast);
}

.footer-links a:hover {
    color: var(--color-primary-light);
}

.footer-copyright p {
    font-size: 0.8rem;
    opacity: 0.5;
}

/* ========================================
   Download Page (hidden link)
   ======================================== */

/* ========================================
   Responsive
   ======================================== */
@media (max-width: 1024px) {
    .about-grid,
    .direction-grid {
        grid-template-columns: repeat(2, 1fr);
    }
}

@media (max-width: 768px) {
    :root {
        --section-padding: 72px 0;
    }

    .nav-links {
        display: none;
        position: fixed;
        top: 0;
        left: 0;
        right: 0;
        bottom: 0;
        background: rgba(10, 45, 31, 0.96);
        flex-direction: column;
        align-items: center;
        justify-content: center;
        gap: 32px;
        z-index: 999;
    }

    .nav-links.active {
        display: flex;
    }

    .nav-links a {
        font-size: 1.2rem;
        color: rgba(255, 255, 255, 0.85);
    }

    .nav-toggle {
        display: flex;
        z-index: 1001;
    }

    .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);
    }

    .about-grid,
    .direction-grid {
        grid-template-columns: 1fr;
    }

    .vision-item {
        flex-direction: column;
        gap: 16px;
    }

    .vision-number {
        width: 48px;
        height: 48px;
        font-size: 1rem;
    }

    .hero-content {
        padding: 100px 0 60px;
    }

    .hero-desc {
        font-size: 0.9rem;
    }

    .footer-content {
        flex-direction: column;
        text-align: center;
    }

    .direction-features {
        grid-template-columns: 1fr;
    }

    .about-quote blockquote::before {
        left: -20px;
        font-size: 3rem;
    }
}

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

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

    .hero-actions {
        flex-direction: column;
        align-items: center;
    }

    .btn {
        width: 100%;
        max-width: 280px;
    }

    .section-title {
        font-size: 1.6rem;
    }

    .about-card,
    .direction-card {
        padding: 28px 20px;
    }

    .contact-item {
        padding: 20px;
    }
}