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

:root {
    --primary: #0A84FF;
    --primary-dark: #0066CC;
    --primary-light: #4DA6FF;
    --primary-lighter: #E8F4FD;
    --accent: #FF6B35;
    --text: #1a1a2e;
    --text-secondary: #555;
    --text-muted: #999;
    --bg: #f8fafc;
    --bg-white: #fff;
    --border: #e8ecf1;
    --shadow: 0 2px 12px rgba(0,0,0,0.06);
    --shadow-lg: 0 8px 40px rgba(0,0,0,0.08);
    --radius: 12px;
    --radius-lg: 20px;
    --transition: 0.3s cubic-bezier(0.4, 0, 0.2, 1);
}

html {
    scroll-behavior: smooth;
}

body {
    font-family: -apple-system, BlinkMacSystemFont, "Segoe UI", "PingFang SC", "Hiragino Sans GB", "Microsoft YaHei", "Helvetica Neue", Helvetica, Arial, sans-serif;
    color: var(--text);
    background: var(--bg-white);
    line-height: 1.6;
    -webkit-font-smoothing: antialiased;
}

a {
    text-decoration: none;
    color: inherit;
}

img {
    max-width: 100%;
}

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

/* ===================== Header ===================== */
.header {
    position: fixed;
    top: 0;
    left: 0;
    right: 0;
    z-index: 1000;
    background: rgba(255,255,255,0.92);
    backdrop-filter: blur(16px);
    -webkit-backdrop-filter: blur(16px);
    border-bottom: 1px solid transparent;
    transition: all var(--transition);
}

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

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

.logo {
    display: flex;
    align-items: center;
    gap: 8px;
    font-size: 20px;
    font-weight: 700;
    color: var(--text);
}

.logo-img {
    width: 36px;
    height: 36px;
    border-radius: 8px;
    object-fit: cover;
}

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

.nav-link {
    padding: 8px 18px;
    border-radius: 8px;
    font-size: 15px;
    color: var(--text-secondary);
    transition: all var(--transition);
    position: relative;
}

.nav-link:hover,
.nav-link.active {
    color: var(--primary);
    background: var(--primary-lighter);
}

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

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

/* ===================== Hero ===================== */
.hero {
    padding: 140px 0 80px;
    background: linear-gradient(160deg, #f0f7ff 0%, #e8f4fd 30%, #f8fafc 100%);
    position: relative;
    overflow: hidden;
}

.hero::before {
    content: '';
    position: absolute;
    top: -200px;
    right: -200px;
    width: 600px;
    height: 600px;
    background: radial-gradient(circle, rgba(10,132,255,0.06) 0%, transparent 70%);
    border-radius: 50%;
}

.hero .container {
    display: flex;
    align-items: center;
    justify-content: space-between;
    gap: 60px;
    position: relative;
}

.hero-content {
    flex: 1;
    min-width: 0;
}

.hero-badge {
    display: inline-block;
    padding: 6px 16px;
    background: var(--primary-lighter);
    color: var(--primary);
    border-radius: 20px;
    font-size: 14px;
    font-weight: 500;
    margin-bottom: 24px;
}

.hero-title {
    font-size: 52px;
    font-weight: 800;
    line-height: 1.2;
    color: var(--text);
    margin-bottom: 24px;
    letter-spacing: -0.5px;
}

.gradient-text {
    background: linear-gradient(135deg, #0A84FF 0%, #4DA6FF 40%, #7C5CFC 100%);
    -webkit-background-clip: text;
    -webkit-text-fill-color: transparent;
    background-clip: text;
}

.hero-desc {
    font-size: 17px;
    color: var(--text-secondary);
    line-height: 1.8;
    margin-bottom: 36px;
}

.hero-buttons {
    display: flex;
    gap: 16px;
    margin-bottom: 48px;
}

.btn {
    display: inline-flex;
    align-items: center;
    gap: 8px;
    padding: 14px 32px;
    border-radius: 12px;
    font-size: 16px;
    font-weight: 600;
    cursor: pointer;
    transition: all var(--transition);
    border: none;
}

.btn-primary {
    background: linear-gradient(135deg, #0A84FF, #4DA6FF);
    color: #fff;
    box-shadow: 0 4px 20px rgba(10,132,255,0.35);
}

.btn-primary:hover {
    transform: translateY(-2px);
    box-shadow: 0 8px 30px rgba(10,132,255,0.45);
}

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

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

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

.stat-item {
    display: flex;
    flex-direction: column;
}

.stat-number {
    font-size: 32px;
    font-weight: 800;
    color: var(--primary);
    line-height: 1.2;
}

.stat-label {
    font-size: 14px;
    color: var(--text-muted);
}

/* Hero Image */
.hero-image {
    position: relative;
    flex-shrink: 0;
}

.hero-img {
    width: 300px;
    max-width: 100%;
    border-radius: 16px;
    box-shadow: 0 16px 40px rgba(10,132,255,0.12);
}

.hero-wave {
    position: absolute;
    bottom: 0;
    left: 0;
    right: 0;
    line-height: 0;
}

.hero-wave svg {
    display: block;
    width: 100%;
    height: 80px;
}

/* ===================== Section Common ===================== */
section {
    padding: 100px 0;
}

.section-header {
    text-align: center;
    max-width: 700px;
    margin: 0 auto 60px;
}

.section-tag {
    display: inline-block;
    padding: 6px 18px;
    background: var(--primary-lighter);
    color: var(--primary);
    border-radius: 20px;
    font-size: 14px;
    font-weight: 600;
    margin-bottom: 16px;
}

.section-title {
    font-size: 38px;
    font-weight: 800;
    color: var(--text);
    margin-bottom: 16px;
    letter-spacing: -0.3px;
}

.section-desc {
    font-size: 17px;
    color: var(--text-secondary);
}

/* ===================== Features ===================== */
.features {
    background: var(--bg);
}

.features-grid {
    display: grid;
    grid-template-columns: repeat(3, 1fr);
    gap: 24px;
}

.feature-card {
    background: var(--bg-white);
    padding: 36px 28px;
    border-radius: var(--radius-lg);
    box-shadow: var(--shadow);
    transition: all var(--transition);
    border: 1px solid transparent;
}

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

.feature-icon {
    font-size: 40px;
    margin-bottom: 20px;
    display: inline-block;
    padding: 12px;
    background: var(--primary-lighter);
    border-radius: 14px;
}

.feature-card h3 {
    font-size: 20px;
    font-weight: 700;
    margin-bottom: 12px;
    color: var(--text);
}

.feature-card p {
    font-size: 15px;
    color: var(--text-secondary);
    line-height: 1.7;
}

/* ===================== AI Section ===================== */
.ai-section {
    background: var(--bg-white);
}

.ai-cards {
    display: grid;
    grid-template-columns: repeat(2, 1fr);
    gap: 32px;
}

.ai-card {
    background: var(--bg);
    border-radius: var(--radius-lg);
    padding: 36px;
    border: 1px solid var(--border);
    transition: all var(--transition);
}

.ai-card:hover {
    box-shadow: var(--shadow-lg);
    border-color: var(--primary-lighter);
}

.ai-card-header {
    display: flex;
    align-items: center;
    gap: 12px;
    margin-bottom: 16px;
}

.ai-icon {
    font-size: 32px;
    padding: 10px;
    background: var(--primary-lighter);
    border-radius: 12px;
}

.ai-card h3 {
    font-size: 22px;
    font-weight: 700;
}

.ai-card > p {
    font-size: 15px;
    color: var(--text-secondary);
    margin-bottom: 24px;
    line-height: 1.7;
}

/* AI chat example */
.ai-example {
    background: var(--bg-white);
    border-radius: var(--radius);
    padding: 20px;
    border: 1px solid var(--border);
}

.ai-chat-bubble {
    padding: 10px 14px;
    border-radius: 10px;
    font-size: 14px;
    line-height: 1.6;
    margin-bottom: 10px;
    max-width: 85%;
}

.ai-chat-bubble.user {
    background: var(--primary-lighter);
    color: var(--primary);
    margin-left: auto;
    text-align: right;
}

.ai-chat-bubble.ai {
    background: var(--bg);
    color: var(--text-secondary);
}

.ai-features-list {
    display: grid;
    grid-template-columns: repeat(2, 1fr);
    gap: 10px;
}

.ai-feature-item {
    padding: 12px;
    background: var(--bg-white);
    border-radius: 8px;
    font-size: 14px;
    color: var(--text-secondary);
    text-align: center;
    border: 1px solid var(--border);
}

/* ===================== Showcase ===================== */
.showcase {
    background: var(--bg);
}

.showcase-grid {
    display: grid;
    grid-template-columns: repeat(4, 1fr);
    gap: 24px;
}

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

.showcase-screen {
    margin-bottom: 16px;
    border-radius: 20px;
    overflow: hidden;
    box-shadow: var(--shadow);
    transition: all var(--transition);
    border: 1px solid var(--border);
    background: var(--bg-white);
}

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

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

.showcase-label {
    font-size: 14px;
    font-weight: 600;
    color: var(--text);
}

/* ===================== About ===================== */
.about {
    background: var(--bg-white);
}

.about-grid {
    display: grid;
    grid-template-columns: 1fr 280px;
    gap: 60px;
    align-items: start;
}

.contact-list {
    margin-top: 32px;
    display: flex;
    flex-direction: column;
    gap: 20px;
}

.contact-item {
    display: flex;
    gap: 16px;
    padding: 20px;
    background: var(--bg);
    border-radius: var(--radius);
    align-items: flex-start;
    transition: all var(--transition);
}

.contact-item:hover {
    box-shadow: var(--shadow);
}

.contact-icon {
    font-size: 24px;
    padding: 12px;
    background: var(--primary-lighter);
    border-radius: 12px;
    flex-shrink: 0;
}

.contact-item strong {
    display: block;
    font-size: 14px;
    color: var(--text-muted);
    margin-bottom: 4px;
    font-weight: 500;
}

.contact-item p {
    font-size: 16px;
    color: var(--text);
    font-weight: 500;
}

.about-qr {
    position: sticky;
    top: 100px;
}

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

.qr-placeholder {
    margin-bottom: 16px;
    display: inline-block;
    border-radius: 8px;
    overflow: hidden;
    box-shadow: var(--shadow);
}

.qr-img {
    display: block;
    width: 160px;
    height: 160px;
    object-fit: cover;
}

.qr-card p {
    font-size: 14px;
    color: var(--text-secondary);
}

/* ===================== Footer ===================== */
.footer {
    background: #1a1a2e;
    color: #aab;
    padding: 60px 0 30px;
}

.footer-content {
    display: flex;
    justify-content: space-between;
    gap: 60px;
    margin-bottom: 40px;
}

.footer-brand {
    flex-shrink: 0;
    max-width: 280px;
}

.footer-logo {
    font-size: 22px;
    font-weight: 700;
    color: #fff;
    margin-bottom: 12px;
    display: flex;
    align-items: center;
    gap: 8px;
}

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

.footer-brand p {
    font-size: 14px;
    color: #889;
    line-height: 1.6;
}

.footer-links {
    display: flex;
    gap: 60px;
}

.footer-col h4 {
    font-size: 15px;
    color: #fff;
    margin-bottom: 16px;
    font-weight: 600;
}

.footer-col a,
.footer-col span {
    display: block;
    font-size: 14px;
    color: #889;
    margin-bottom: 10px;
    transition: color var(--transition);
}

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

.footer-bottom {
    border-top: 1px solid rgba(255,255,255,0.08);
    padding-top: 24px;
    text-align: center;
    font-size: 13px;
    color: #667;
}

.footer-bottom p {
    margin-bottom: 4px;
}

.footer-bottom a {
    color: #667;
}

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

/* ===================== Back to Top ===================== */
.back-to-top {
    position: fixed;
    bottom: 32px;
    right: 32px;
    width: 44px;
    height: 44px;
    background: var(--primary);
    color: #fff;
    border: none;
    border-radius: 50%;
    font-size: 20px;
    cursor: pointer;
    box-shadow: 0 4px 16px rgba(10,132,255,0.35);
    transition: all var(--transition);
    opacity: 0;
    visibility: hidden;
    transform: translateY(10px);
    z-index: 999;
}

.back-to-top.visible {
    opacity: 1;
    visibility: visible;
    transform: translateY(0);
}

.back-to-top:hover {
    background: var(--primary-dark);
    transform: translateY(-2px);
}

/* ===================== Responsive ===================== */
@media (max-width: 1024px) {
    .hero .container {
        flex-direction: column;
        gap: 48px;
    }

    .hero-image {
        order: -1;
    }

    .hero-img {
        width: 260px;
    }

    .hero-title {
        font-size: 40px;
    }

    .features-grid {
        grid-template-columns: repeat(2, 1fr);
    }

    .ai-cards {
        grid-template-columns: 1fr;
    }

    .showcase-grid {
        grid-template-columns: repeat(2, 1fr);
    }

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

    .about-qr {
        order: -1;
        position: static;
    }

    .qr-card {
        max-width: 280px;
        margin: 0 auto;
    }

    .footer-content {
        flex-direction: column;
        gap: 32px;
    }

    .footer-links {
        gap: 40px;
    }
}

@media (max-width: 768px) {
    .header .container {
        height: 60px;
    }

    .nav {
        position: fixed;
        top: 60px;
        left: 0;
        right: 0;
        background: var(--bg-white);
        flex-direction: column;
        padding: 16px;
        gap: 4px;
        box-shadow: var(--shadow-lg);
        transform: translateY(-100%);
        opacity: 0;
        pointer-events: none;
        transition: all var(--transition);
    }

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

    .menu-toggle {
        display: flex;
    }

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

    .hero-title {
        font-size: 32px;
    }

    .hero-stats {
        gap: 24px;
    }

    .stat-number {
        font-size: 24px;
    }

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

    .showcase-grid {
        grid-template-columns: 1fr 1fr;
        gap: 16px;
    }

    .section-title {
        font-size: 28px;
    }

    section {
        padding: 60px 0;
    }

    .footer-links {
        flex-wrap: wrap;
        gap: 24px;
    }
}