/*
Theme Name: KuaiLian SEO Theme
Theme URI: https://kuailianng.com.cn
Description: A high-performance, SEO/GEO-optimized WordPress theme using semantic HTML5 and vanilla CSS.
Version: 1.0.0
Author: Antigravity
Author URI: https://google.deepmind.com
Text Domain: kuailian-seo
*/

/* ==========================================================================
   1. Design System (CSS Variables)
   ========================================================================== */
:root {
    /* Brand Colors - Premium Blue Palette */
    --color-primary: #2563EB;
    /* Vivid Blue */
    --color-primary-dark: #1E40AF;
    /* Deep Blue for Hover */
    --color-secondary: #0F172A;
    /* Dark Slate (Headings) */
    --color-accent: #10B981;
    /* Success/Safe Green */
    --color-surface: #FFFFFF;
    /* Pure White */
    --color-background: #F8FAFC;
    /* Light Grayish Blue Background */
    --color-text-body: #475569;
    /* Slate Grey for readability */
    --color-text-light: #94A3B8;
    /* Muted text */

    /* Typography */
    --font-sans: 'Inter', system-ui, -apple-system, BlinkMacSystemFont, "Segoe UI", Roboto, "Helvetica Neue", Arial, sans-serif;
    --line-height-base: 1.6;
    --line-height-heading: 1.2;

    /* Spacing & Layout */
    --container-width: 1200px;
    --spacing-xs: 0.5rem;
    /* 8px */
    --spacing-sm: 1rem;
    /* 16px */
    --spacing-md: 2rem;
    /* 32px */
    --spacing-lg: 4rem;
    /* 64px */
    --spacing-xl: 8rem;
    /* 128px */

    /* Effects */
    --shadow-sm: 0 1px 2px 0 rgb(0 0 0 / 0.05);
    --shadow-md: 0 4px 6px -1px rgb(0 0 0 / 0.1), 0 2px 4px -2px rgb(0 0 0 / 0.1);
    --shadow-lg: 0 10px 15px -3px rgb(0 0 0 / 0.1), 0 4px 6px -4px rgb(0 0 0 / 0.1);
    --shadow-glow: 0 0 20px rgba(37, 99, 235, 0.2);
    --radius-md: 0.5rem;
    --radius-lg: 1rem;
    --radius-full: 9999px;
}

/* ==========================================================================
   2. Reset & Base (Core Web Vitals Optimized)
   ========================================================================== */
*,
*::before,
*::after {
    box-sizing: border-box;
    margin: 0;
    padding: 0;
}

html {
    scroll-behavior: smooth;
    font-size: 100%;
}

body {
    font-family: var(--font-sans);
    color: var(--color-text-body);
    background-color: var(--color-background);
    line-height: var(--line-height-base);
    -webkit-font-smoothing: antialiased;
    text-rendering: optimizeLegibility;
}

/* Typography Hierarchy (SEO Friendly) */
h1,
h2,
h3,
h4,
h5,
h6 {
    color: var(--color-secondary);
    line-height: var(--line-height-heading);
    font-weight: 700;
    margin-bottom: var(--spacing-sm);
}

h1 {
    font-size: clamp(2.5rem, 5vw, 3.75rem);
    letter-spacing: -0.02em;
}

h2 {
    font-size: clamp(2rem, 4vw, 2.5rem);
    letter-spacing: -0.01em;
}

h3 {
    font-size: 1.5rem;
}

p {
    margin-bottom: var(--spacing-sm);
}

a {
    color: var(--color-primary);
    text-decoration: none;
    transition: color 0.2s ease;
}

a:hover {
    color: var(--color-primary-dark);
}

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

/* ==========================================================================
   3. Layout Components
   ========================================================================== */
.container {
    width: 100%;
    max-width: var(--container-width);
    margin: 0 auto;
    padding: 0 var(--spacing-sm);
}

.btn {
    display: inline-flex;
    align-items: center;
    justify-content: center;
    padding: 0.75rem 1.5rem;
    font-weight: 600;
    border-radius: var(--radius-full);
    transition: all 0.3s cubic-bezier(0.4, 0, 0.2, 1);
    cursor: pointer;
    font-size: 1rem;
}

.btn-primary {
    background-color: var(--color-primary);
    color: white;
    box-shadow: var(--shadow-glow);
}

.btn-primary:hover {
    background-color: var(--color-primary-dark);
    transform: translateY(-2px);
    box-shadow: var(--shadow-lg);
}

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

.btn-outline:hover {
    background-color: var(--color-secondary);
    color: white;
}

/* ==========================================================================
   4. Header & Navigation
   ========================================================================== */
.site-header {
    background: rgba(255, 255, 255, 0.9);
    backdrop-filter: blur(10px);
    position: sticky;
    top: 0;
    z-index: 1000;
    border-bottom: 1px solid rgba(0, 0, 0, 0.05);
    padding: var(--spacing-sm) 0;
}

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

.site-logo {
    font-weight: 800;
    font-size: 1.5rem;
    color: var(--color-secondary);
    display: flex;
    align-items: center;
    gap: 0.5rem;
}

.main-navigation ul {
    display: flex;
    gap: var(--spacing-md);
    list-style: none;
}

.main-navigation a {
    color: var(--color-secondary);
    font-weight: 500;
}

/* ==========================================================================
   5. Hero Section
   ========================================================================== */
.hero-section {
    padding: var(--spacing-xl) 0 var(--spacing-lg);
    background: linear-gradient(135deg, #EFF6FF 0%, #FFFFFF 100%);
    overflow: hidden;
    position: relative;
}

.hero-grid {
    display: grid;
    grid-template-columns: 1fr 1fr;
    gap: var(--spacing-md);
    align-items: center;
}

.hero-content h1 {
    margin-bottom: var(--spacing-md);
}

.hero-content .lead {
    font-size: 1.25rem;
    color: var(--color-text-body);
    margin-bottom: var(--spacing-md);
    max-width: 540px;
}

.hero-badges {
    display: flex;
    gap: var(--spacing-md);
    margin-top: var(--spacing-md);
    color: var(--color-text-body);
    font-size: 0.875rem;
}

/* ==========================================================================
   6. Features Grid
   ========================================================================== */
.features-section {
    padding: var(--spacing-lg) 0;
}

.section-header {
    text-align: center;
    max-width: 700px;
    margin: 0 auto var(--spacing-lg);
}

.features-grid {
    display: grid;
    grid-template-columns: repeat(auto-fit, minmax(300px, 1fr));
    gap: var(--spacing-md);
}

.feature-card {
    background: var(--color-surface);
    padding: var(--spacing-md);
    border-radius: var(--radius-lg);
    box-shadow: var(--shadow-sm);
    transition: transform 0.3s ease, box-shadow 0.3s ease;
    border: 1px solid rgba(0, 0, 0, 0.03);
}

.feature-card:hover {
    transform: translateY(-5px);
    box-shadow: var(--shadow-md);
}

.feature-icon {
    width: 48px;
    height: 48px;
    background: #EFF6FF;
    color: var(--color-primary);
    border-radius: 12px;
    display: flex;
    align-items: center;
    justify-content: center;
    margin-bottom: var(--spacing-sm);
}

/* ==========================================================================
   7. Device Support
   ========================================================================== */
.devices-section {
    background-color: #F1F5F9;
    padding: var(--spacing-lg) 0;
    text-align: center;
}

.device-grid {
    display: flex;
    justify-content: center;
    gap: var(--spacing-md);
    flex-wrap: wrap;
    margin-top: var(--spacing-md);
}

.device-item {
    background: white;
    padding: var(--spacing-md);
    border-radius: var(--radius-md);
    min-width: 140px;
    box-shadow: var(--shadow-sm);
}

/* ==========================================================================
   8. Footer
   ========================================================================== */
.site-footer {
    background: var(--color-secondary);
    color: rgba(255, 255, 255, 0.8);
    padding: var(--spacing-lg) 0 var(--spacing-md);
    font-size: 0.875rem;
}

.footer-grid {
    display: grid;
    grid-template-columns: 2fr 1fr 1fr 1fr;
    gap: var(--spacing-lg);
    margin-bottom: var(--spacing-lg);
}

.footer-col h4 {
    color: white;
    margin-bottom: var(--spacing-sm);
}

.footer-col ul {
    list-style: none;
}

.footer-col li {
    margin-bottom: 0.5rem;
}

.footer-col a {
    color: rgba(255, 255, 255, 0.6);
}

.footer-col a:hover {
    color: white;
}

/* Mobile Responsive */
@media (max-width: 768px) {
    .hero-grid {
        grid-template-columns: 1fr;
        text-align: center;
    }

    .hero-content .lead {
        margin: 0 auto var(--spacing-md);
    }

    .hero-buttons {
        justify-content: center;
    }

    .nav-wrapper {
        flex-direction: column;
        gap: var(--spacing-sm);
    }

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

/* ==========================================================================
   9. New Modules & Enhancements
   ========================================================================== */
.card {
    background: var(--color-surface);
    border-radius: var(--radius-lg);
    border: 1px solid rgba(0, 0, 0, 0.05);
    padding: var(--spacing-md);
    transition: all 0.3s ease;
}



.device-item.card:hover {
    transform: translateY(-8px);
    box-shadow: var(--shadow-lg);
}

.btn-text {
    display: inline-block;
    margin-top: 1rem;
    font-weight: 600;
    color: var(--color-primary);
}

  /* How It Works */
        .how-it-works {
            padding: 7rem 0;
            background: var(--light);
        }

        .process-steps {
            display: grid;
            grid-template-columns: repeat(auto-fit, minmax(250px, 1fr));
            gap: 2rem;
            margin-top: 3rem;
        }

        .process-step {
            text-align: center;
            position: relative;
        }

        .step-icon {
            width: 100px;
            height: 100px;
            background: linear-gradient(135deg, var(--primary), var(--secondary));
            border-radius: 50%;
            display: flex;
            align-items: center;
            justify-content: center;
            margin: 0 auto 2rem;
            font-size: 2.5rem;
            color: white;
            box-shadow: 0 15px 30px rgba(108, 92, 231, 0.3);
        }

        .step-number {
            position: absolute;
            top: 0;
            left: 50%;
            transform: translateX(-50%);
            width: 40px;
            height: 40px;
            background: white;
            border: 3px solid var(--primary);
            border-radius: 50%;
            display: flex;
            align-items: center;
            justify-content: center;
            font-weight: bold;
            color: var(--primary);
        }

        .process-step h3 {
            margin-bottom: 1rem;
            color: var(--dark);
        }

        .process-step p {
            color: var(--gray);
        }


/* FAQ Styles */
.faq-item summary::-webkit-details-marker {
    display: none;
}

.faq-item[open] summary .icon {
    transform: rotate(180deg);
}

.faq-item:hover summary {
    color: var(--color-primary);
}

/* Footer Corrections */
.footer-title {
    color: white;
    font-size: 1rem;
    margin-bottom: 1.5rem;
}

.footer-links ul {
    list-style: none;
    padding: 0;
}

.footer-links li {
    margin-bottom: 0.75rem;
}

.footer-links a {
    color: var(--color-text-light);
    transition: color 0.2s;
}

.footer-links a:hover {
    color: white;
}


            
/* Animations */
@keyframes fadeInUp {
    from {
        opacity: 0;
        transform: translateY(20px);
    }

    to {
        opacity: 1;
        transform: translateY(0);
    }
}

.animate-fade-in-up {
    animation: fadeInUp 0.8s ease forwards;
}