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

:root {
    --primary: #2563eb;
    --primary-dark: #1d4ed8;
    --primary-light: #3b82f6;
    --accent: #06b6d4;
    --dark: #0f172a;
    --dark-2: #1e293b;
    --gray-900: #111827;
    --gray-700: #374151;
    --gray-500: #6b7280;
    --gray-300: #d1d5db;
    --gray-100: #f3f4f6;
    --white: #ffffff;
    --radius: 12px;
    --shadow: 0 4px 24px rgba(0,0,0,0.08);
    --shadow-lg: 0 20px 60px rgba(0,0,0,0.15);
    --transition: 0.3s cubic-bezier(0.4, 0, 0.2, 1);
}

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

body {
    font-family: -apple-system, BlinkMacSystemFont, 'PingFang SC', 'Microsoft YaHei', 'Helvetica Neue', sans-serif;
    color: var(--gray-700);
    line-height: 1.7;
    background: var(--white);
    overflow-x: hidden;
}

.container { max-width: 1200px; margin: 0 auto; padding: 0 24px; }
a { text-decoration: none; color: inherit; }
img { max-width: 100%; display: block; }

/* ====== Buttons ====== */
.btn {
    display: inline-flex; align-items: center; justify-content: center;
    padding: 14px 32px; border-radius: 50px; font-size: 1rem; font-weight: 500;
    cursor: pointer; transition: var(--transition); border: none; text-decoration: none;
}
.btn-primary {
    background: var(--primary); color: var(--white);
    box-shadow: 0 4px 20px rgba(37,99,235,0.4);
}
.btn-primary:hover { background: var(--primary-dark); transform: translateY(-2px); box-shadow: 0 8px 30px rgba(37,99,235,0.5); }
.btn-outline {
    background: transparent; color: var(--white); border: 2px solid rgba(255,255,255,0.5);
}
.btn-outline:hover { background: rgba(255,255,255,0.1); border-color: var(--white); }
.btn-full { width: 100%; }

/* ====== Navbar ====== */
.navbar {
    position: fixed; top: 0; left: 0; right: 0; z-index: 1000;
    padding: 16px 0; transition: var(--transition);
}
.navbar.scrolled {
    background: rgba(255,255,255,0.95); backdrop-filter: blur(20px);
    box-shadow: 0 2px 20px rgba(0,0,0,0.08); padding: 10px 0;
}
.nav-container { display: flex; align-items: center; justify-content: space-between; }
.logo { display: flex; align-items: center; gap: 10px; font-size: 1.25rem; font-weight: 700; }
.logo-icon {
    font-size: 1.5rem; color: var(--primary);
    animation: pulse 2s infinite;
}
@keyframes pulse { 0%,100%{opacity:1} 50%{opacity:0.6} }
.logo-text { color: var(--white); transition: var(--transition); }
.navbar.scrolled .logo-text { color: var(--dark); }

.nav-menu { display: flex; align-items: center; gap: 8px; }
.nav-link {
    padding: 8px 16px; border-radius: 8px; font-size: 0.9rem; font-weight: 500;
    color: rgba(255,255,255,0.8); transition: var(--transition);
}
.nav-link:hover, .nav-link.active { color: var(--white); background: rgba(255,255,255,0.1); }
.navbar.scrolled .nav-link { color: var(--gray-700); }
.navbar.scrolled .nav-link:hover, .navbar.scrolled .nav-link.active { color: var(--primary); background: rgba(37,99,235,0.08); }

.nav-toggle { display: none; flex-direction: column; gap: 5px; background: none; border: none; cursor: pointer; padding: 4px; }
.nav-toggle span { width: 24px; height: 2px; background: var(--white); transition: var(--transition); border-radius: 2px; }
.navbar.scrolled .nav-toggle span { background: var(--dark); }

/* ====== Hero ====== */
.hero {
    position: relative; min-height: 100vh; display: flex; align-items: center;
    overflow: hidden; padding: 120px 0 80px;
}
.hero-bg {
    position: absolute; inset: 0;
    background: linear-gradient(135deg, #0f172a 0%, #1e3a5f 40%, #1e40af 100%);
}
.hero-bg::before {
    content: ''; position: absolute; inset: 0;
    background: radial-gradient(ellipse at 70% 20%, rgba(6,182,212,0.15), transparent 60%),
                radial-gradient(ellipse at 30% 80%, rgba(37,99,235,0.2), transparent 50%);
}
.hero-particles { position: absolute; inset: 0; pointer-events: none; }

.hero-content { position: relative; z-index: 2; max-width: 800px; }
.hero-badge {
    display: inline-block; padding: 8px 20px; border-radius: 50px;
    background: rgba(255,255,255,0.1); border: 1px solid rgba(255,255,255,0.2);
    color: var(--accent); font-size: 0.85rem; font-weight: 500; margin-bottom: 24px;
    backdrop-filter: blur(10px);
}
.hero-title { color: var(--white); font-size: clamp(2.5rem, 6vw, 4rem); font-weight: 900; line-height: 1.15; margin-bottom: 24px; }
.hero-title .line { display: block; }
.hero-title .highlight {
    background: linear-gradient(135deg, var(--accent), var(--primary-light));
    -webkit-background-clip: text; -webkit-text-fill-color: transparent; background-clip: text;
}
.hero-desc { color: rgba(255,255,255,0.75); font-size: 1.1rem; max-width: 600px; margin-bottom: 40px; line-height: 1.8; }
.hero-actions { display: flex; gap: 16px; margin-bottom: 60px; flex-wrap: wrap; }

.hero-stats { display: grid; grid-template-columns: repeat(4, 1fr); gap: 32px; }
.stat-item { text-align: left; }
.stat-num { font-size: 2.5rem; font-weight: 900; color: var(--white); line-height: 1; }
.stat-suffix { font-size: 1.5rem; font-weight: 700; color: var(--accent); }
.stat-label { display: block; color: rgba(255,255,255,0.6); font-size: 0.85rem; margin-top: 4px; }

.hero-scroll {
    position: absolute; bottom: 40px; left: 50%; transform: translateX(-50%);
    display: flex; flex-direction: column; align-items: center; gap: 8px;
    color: rgba(255,255,255,0.5); font-size: 0.75rem; letter-spacing: 2px;
}
.scroll-line { width: 1px; height: 40px; background: rgba(255,255,255,0.3); animation: scrollAnim 2s infinite; }
@keyframes scrollAnim { 0%{transform:scaleY(0);transform-origin:top} 50%{transform:scaleY(1);transform-origin:top} 51%{transform-origin:bottom} 100%{transform:scaleY(0);transform-origin:bottom} }

/* ====== Section Common ====== */
.section { padding: 120px 0; }
.section-header { text-align: center; margin-bottom: 64px; }
.section-tag {
    display: inline-block; font-size: 0.8rem; font-weight: 700; letter-spacing: 3px;
    color: var(--primary); text-transform: uppercase; margin-bottom: 12px;
}
.section-title { font-size: clamp(1.8rem, 4vw, 2.5rem); font-weight: 900; color: var(--dark); margin-bottom: 16px; }
.section-line { width: 48px; height: 3px; background: linear-gradient(90deg, var(--primary), var(--accent)); margin: 0 auto 16px; border-radius: 2px; }
.section-desc { color: var(--gray-500); font-size: 1.05rem; max-width: 600px; margin: 0 auto; }

/* ====== About ====== */
.about { background: var(--gray-100); }
.about-grid { display: grid; grid-template-columns: 1fr 1fr; gap: 60px; align-items: center; }
.about-text h3 { font-size: 1.5rem; font-weight: 700; color: var(--dark); margin-bottom: 20px; line-height: 1.5; }
.about-text p { margin-bottom: 16px; color: var(--gray-700); line-height: 1.9; }
.about-tags { display: flex; flex-wrap: wrap; gap: 10px; margin-top: 24px; }
.tag {
    padding: 6px 16px; border-radius: 50px; font-size: 0.8rem; font-weight: 500;
    background: rgba(37,99,235,0.1); color: var(--primary);
}
.about-card-stack { display: flex; flex-direction: column; gap: 20px; }
.about-card {
    display: flex; align-items: flex-start; gap: 20px; padding: 28px;
    background: var(--white); border-radius: var(--radius); box-shadow: var(--shadow);
    transition: var(--transition);
}
.about-card:hover { transform: translateX(8px); box-shadow: var(--shadow-lg); }
.card-icon { font-size: 2rem; flex-shrink: 0; }
.card-info strong { display: block; color: var(--dark); font-size: 1rem; margin-bottom: 4px; }
.card-info p { font-size: 0.9rem; color: var(--gray-500); margin: 0; }

/* ====== Services ====== */
.services-grid { display: grid; grid-template-columns: repeat(3, 1fr); gap: 24px; }
.service-card {
    padding: 40px 32px; border-radius: var(--radius); background: var(--white);
    border: 1px solid var(--gray-300); transition: var(--transition); position: relative; overflow: hidden;
}
.service-card::before {
    content: ''; position: absolute; top: 0; left: 0; right: 0; height: 3px;
    background: linear-gradient(90deg, var(--primary), var(--accent));
    transform: scaleX(0); transition: var(--transition);
}
.service-card:hover { transform: translateY(-8px); box-shadow: var(--shadow-lg); border-color: transparent; }
.service-card:hover::before { transform: scaleX(1); }
.service-icon { width: 56px; height: 56px; color: var(--primary); margin-bottom: 24px; }
.service-icon svg { width: 100%; height: 100%; }
.service-card h3 { font-size: 1.2rem; font-weight: 700; color: var(--dark); margin-bottom: 12px; }
.service-card p { font-size: 0.9rem; color: var(--gray-500); margin-bottom: 16px; line-height: 1.8; }
.service-list { list-style: none; }
.service-list li {
    padding: 6px 0 6px 20px; font-size: 0.85rem; color: var(--gray-700); position: relative;
}
.service-list li::before {
    content: ''; position: absolute; left: 0; top: 13px; width: 8px; height: 8px;
    border-radius: 50%; background: var(--accent);
}

/* ====== Advantages ====== */
.advantages { background: var(--dark); }
.advantages .section-tag { color: var(--accent); }
.advantages .section-title { color: var(--white); }
.advantages .section-line { background: linear-gradient(90deg, var(--accent), var(--primary)); }
.advantages-grid { display: grid; grid-template-columns: repeat(2, 1fr); gap: 24px; }
.advantage-item {
    display: flex; gap: 24px; padding: 32px; border-radius: var(--radius);
    background: rgba(255,255,255,0.03); border: 1px solid rgba(255,255,255,0.08);
    transition: var(--transition);
}
.advantage-item:hover { background: rgba(255,255,255,0.06); border-color: rgba(6,182,212,0.3); transform: translateX(4px); }
.advantage-num {
    font-size: 2rem; font-weight: 900; color: var(--accent); opacity: 0.5;
    flex-shrink: 0; line-height: 1;
}
.advantage-content h3 { font-size: 1.1rem; font-weight: 700; color: var(--white); margin-bottom: 8px; }
.advantage-content p { font-size: 0.9rem; color: rgba(255,255,255,0.6); line-height: 1.8; }

/* ====== Cases ====== */
.cases { background: var(--gray-100); }
.cases-grid { display: grid; grid-template-columns: repeat(2, 1fr); gap: 24px; }
.case-card {
    border-radius: var(--radius); overflow: hidden; background: var(--white);
    box-shadow: var(--shadow); transition: var(--transition);
}
.case-card:hover { transform: translateY(-6px); box-shadow: var(--shadow-lg); }
.case-img {
    height: 200px; display: flex; align-items: center; justify-content: center;
}
.case-icon { font-size: 4rem; filter: drop-shadow(0 4px 8px rgba(0,0,0,0.2)); }
.case-body { padding: 28px; }
.case-tag {
    display: inline-block; padding: 4px 12px; border-radius: 50px; font-size: 0.75rem;
    font-weight: 600; background: rgba(37,99,235,0.1); color: var(--primary); margin-bottom: 12px;
}
.case-body h3 { font-size: 1.1rem; font-weight: 700; color: var(--dark); margin-bottom: 10px; }
.case-body p { font-size: 0.9rem; color: var(--gray-500); line-height: 1.8; }

/* ====== Contact ====== */
.contact-grid { display: grid; grid-template-columns: 1fr 1fr; gap: 60px; }
.contact-info { display: flex; flex-direction: column; gap: 28px; }
.contact-item { display: flex; gap: 16px; align-items: flex-start; }
.contact-icon {
    width: 48px; height: 48px; border-radius: 12px; flex-shrink: 0;
    background: rgba(37,99,235,0.1); color: var(--primary);
    display: flex; align-items: center; justify-content: center;
}
.contact-icon svg { width: 22px; height: 22px; }
.contact-item strong { display: block; color: var(--dark); font-size: 0.95rem; margin-bottom: 2px; }
.contact-item p { font-size: 0.9rem; color: var(--gray-500); margin: 0; }

.contact-form { background: var(--gray-100); padding: 40px; border-radius: var(--radius); }
.form-row { display: grid; grid-template-columns: 1fr 1fr; gap: 16px; }
.form-group { margin-bottom: 16px; }
.form-group label { display: block; font-size: 0.85rem; font-weight: 600; color: var(--dark); margin-bottom: 6px; }
.form-group input, .form-group textarea {
    width: 100%; padding: 12px 16px; border: 1px solid var(--gray-300); border-radius: 8px;
    font-size: 0.9rem; font-family: inherit; transition: var(--transition); background: var(--white);
}
.form-group input:focus, .form-group textarea:focus {
    outline: none; border-color: var(--primary); box-shadow: 0 0 0 3px rgba(37,99,235,0.1);
}
.form-group textarea { resize: vertical; }

/* ====== Footer ====== */
.footer { background: var(--dark); padding: 60px 0 0; }
.footer-grid { display: grid; grid-template-columns: 2fr 1fr 1fr 1fr; gap: 40px; padding-bottom: 40px; border-bottom: 1px solid rgba(255,255,255,0.08); }
.footer-brand .logo { margin-bottom: 16px; }
.footer-brand .logo-text { color: var(--white); }
.footer-brand p { color: rgba(255,255,255,0.5); font-size: 0.9rem; line-height: 1.8; }
.footer-links h4 { color: var(--white); font-size: 0.95rem; margin-bottom: 16px; }
.footer-links a { display: block; color: rgba(255,255,255,0.5); font-size: 0.85rem; padding: 4px 0; transition: var(--transition); }
.footer-links a:hover { color: var(--accent); }
.footer-bottom { padding: 24px 0; text-align: center; }
.footer-bottom p { color: rgba(255,255,255,0.3); font-size: 0.8rem; }

/* ====== Back to Top ====== */
.back-to-top {
    position: fixed; bottom: 32px; right: 32px; width: 48px; height: 48px;
    border-radius: 50%; background: var(--primary); color: var(--white); border: none;
    display: flex; align-items: center; justify-content: center; cursor: pointer;
    opacity: 0; transform: translateY(20px); transition: var(--transition); z-index: 999;
    box-shadow: 0 4px 20px rgba(37,99,235,0.4);
}
.back-to-top.show { opacity: 1; transform: translateY(0); }
.back-to-top:hover { background: var(--primary-dark); transform: translateY(-2px); }
.back-to-top svg { width: 20px; height: 20px; }

/* ====== Fade In Animation ====== */
.fade-in { opacity: 0; transform: translateY(30px); transition: opacity 0.6s, transform 0.6s; }
.fade-in.visible { opacity: 1; transform: translateY(0); }

/* ====== Responsive ====== */
@media (max-width: 1024px) {
    .services-grid { grid-template-columns: repeat(2, 1fr); }
    .hero-stats { grid-template-columns: repeat(2, 1fr); gap: 24px; }
    .footer-grid { grid-template-columns: 1fr 1fr; }
}
@media (max-width: 768px) {
    .nav-menu {
        position: fixed; top: 0; right: -100%; width: 75%; height: 100vh;
        background: var(--white); flex-direction: column; padding: 80px 32px;
        transition: var(--transition); box-shadow: var(--shadow-lg);
    }
    .nav-menu.open { right: 0; }
    .nav-menu .nav-link { color: var(--gray-700); font-size: 1.1rem; padding: 12px 0; }
    .nav-toggle { display: flex; }
    .about-grid, .contact-grid { grid-template-columns: 1fr; gap: 40px; }
    .services-grid, .cases-grid, .advantages-grid { grid-template-columns: 1fr; }
    .hero-stats { grid-template-columns: repeat(2, 1fr); }
    .footer-grid { grid-template-columns: 1fr; gap: 32px; }
    .section { padding: 80px 0; }
    .form-row { grid-template-columns: 1fr; }
}