/* ========================================
   气体检测 - 首页样式
   ======================================== */

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

html {
    scroll-behavior: smooth;
}

body {
    font-family: -apple-system, BlinkMacSystemFont, "Segoe UI", "PingFang SC",
        "Microsoft YaHei", "Helvetica Neue", Arial, sans-serif;
    font-weight: 400;
    font-size: 16px;
    line-height: 1.6;
    color: #1e293b;
    -webkit-font-smoothing: antialiased;
    -moz-osx-font-smoothing: grayscale;
}

a {
    text-decoration: none;
    transition: all 0.3s ease;
}

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

.container {
    max-width: 1100px;
    margin: 0 auto;
    padding: 0 24px;
}

/* --- Hero Section --- */
.hero {
    position: relative;
    min-height: 100vh;
    display: flex;
    align-items: center;
    justify-content: center;
    overflow: hidden;
    background: linear-gradient(135deg, #0f172a 0%, #1e3a5f 40%, #1e40af 100%);
}

.hero-bg {
    position: absolute;
    inset: 0;
    background:
        radial-gradient(ellipse at 20% 50%, rgba(37, 99, 235, 0.15) 0%, transparent 50%),
        radial-gradient(ellipse at 80% 20%, rgba(56, 189, 248, 0.1) 0%, transparent 50%),
        radial-gradient(ellipse at 50% 80%, rgba(59, 130, 246, 0.08) 0%, transparent 50%);
}

.hero-content {
    position: relative;
    z-index: 1;
    text-align: center;
    padding: 40px 24px 100px;
    max-width: 800px;
    animation: fadeInUp 0.8s ease-out;
}

.hero-badge {
    display: inline-block;
    padding: 6px 20px;
    border-radius: 20px;
    font-size: 14px;
    font-weight: 500;
    color: #93c5fd;
    background: rgba(59, 130, 246, 0.15);
    border: 1px solid rgba(59, 130, 246, 0.3);
    margin-bottom: 24px;
    letter-spacing: 1px;
}

.hero-title {
    font-size: clamp(36px, 7vw, 64px);
    font-weight: 800;
    color: #ffffff;
    letter-spacing: 2px;
    margin-bottom: 20px;
    text-shadow: 0 2px 20px rgba(0, 0, 0, 0.2);
}

.hero-subtitle {
    font-size: clamp(15px, 2vw, 19px);
    color: rgba(255, 255, 255, 0.75);
    line-height: 1.8;
    margin-bottom: 36px;
}

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

.btn {
    display: inline-block;
    padding: 14px 36px;
    border-radius: 8px;
    font-size: 16px;
    font-weight: 600;
    cursor: pointer;
    transition: all 0.3s ease;
    border: none;
}

.btn-primary {
    background: #2563eb;
    color: #ffffff;
    box-shadow: 0 4px 14px rgba(37, 99, 235, 0.4);
}

.btn-primary:hover {
    background: #1d4ed8;
    box-shadow: 0 6px 20px rgba(37, 99, 235, 0.5);
    transform: translateY(-1px);
    color: #ffffff;
}

.btn-outline {
    background: transparent;
    color: #ffffff;
    border: 2px solid rgba(255, 255, 255, 0.3);
}

.btn-outline:hover {
    border-color: #ffffff;
    background: rgba(255, 255, 255, 0.1);
    color: #ffffff;
}

/* --- Hero Wave --- */
.hero-wave {
    position: absolute;
    bottom: -1px;
    left: 0;
    width: 100%;
    line-height: 0;
    z-index: 2;
}

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

/* --- Features Section --- */
.features {
    padding: 80px 0 100px;
    background: #ffffff;
}

.section-header {
    text-align: center;
    margin-bottom: 60px;
}

.section-header h2 {
    font-size: 32px;
    font-weight: 700;
    color: #0f172a;
    margin-bottom: 12px;
}

.section-header h2::after {
    content: '';
    display: block;
    width: 50px;
    height: 3px;
    background: #2563eb;
    border-radius: 2px;
    margin: 16px auto 0;
}

.section-header p {
    font-size: 16px;
    color: #64748b;
    margin-top: 16px;
}

.features-grid {
    display: grid;
    grid-template-columns: repeat(3, 1fr);
    gap: 30px;
}

.feature-card {
    background: #f8fafc;
    border: 1px solid #e2e8f0;
    border-radius: 12px;
    padding: 40px 28px;
    text-align: center;
    transition: all 0.35s ease;
}

.feature-card:hover {
    transform: translateY(-6px);
    box-shadow: 0 12px 30px rgba(37, 99, 235, 0.1);
    border-color: #bfdbfe;
}

.feature-icon {
    margin-bottom: 20px;
    display: inline-block;
}

.feature-card h3 {
    font-size: 20px;
    font-weight: 600;
    color: #0f172a;
    margin-bottom: 12px;
}

.feature-card p {
    font-size: 15px;
    color: #64748b;
    line-height: 1.7;
}

/* --- Footer --- */
.footer {
    background: #0f172a;
    padding: 32px 0;
    text-align: center;
}

.footer p {
    font-size: 14px;
    color: rgba(255, 255, 255, 0.4);
    margin-bottom: 4px;
}

.footer a {
    color: rgba(255, 255, 255, 0.4);
}

.footer a:hover {
    color: #93c5fd;
}

/* --- Animations --- */
@keyframes fadeInUp {
    from {
        opacity: 0;
        transform: translateY(30px);
    }
    to {
        opacity: 1;
        transform: translateY(0);
    }
}

/* --- Responsive: Tablet --- */
@media (max-width: 768px) {
    .hero {
        min-height: 90vh;
    }

    .hero-content {
        padding: 40px 20px 80px;
    }

    .hero-wave svg {
        height: 50px;
    }

    .features {
        padding: 60px 0 70px;
    }

    .section-header h2 {
        font-size: 28px;
    }

    .features-grid {
        grid-template-columns: repeat(2, 1fr);
        gap: 20px;
    }

    .feature-card {
        padding: 30px 20px;
    }
}

/* --- Responsive: Mobile --- */
@media (max-width: 480px) {
    .hero {
        min-height: 85vh;
    }

    .hero-content {
        padding: 30px 16px 70px;
    }

    .hero-badge {
        font-size: 12px;
        padding: 4px 16px;
    }

    .hero-wave svg {
        height: 36px;
    }

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

    .btn {
        width: 100%;
        max-width: 260px;
        text-align: center;
    }

    .features {
        padding: 50px 0 60px;
    }

    .features-grid {
        grid-template-columns: 1fr;
        gap: 18px;
    }

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

    .section-header h2 {
        font-size: 24px;
    }
}