/* ==========================================================================
   AI-4-Contractors.com — Global Design System
   Based on GeothermalInsider.com pattern
   ========================================================================== */

/* --- CSS Variables --- */
:root {
    --primary: #2563EB;
    --primary-hover: #1D4ED8;
    --primary-light: #DBEAFE;
    --accent: #F59E0B;
    --accent-hover: #D97706;
    --dark: #0F172A;
    --dark-card: #1E293B;
    --dark-text: #334155;
    --muted: #64748B;
    --cream: #F8FAFC;
    --cream-deep: #F1F5F9;
    --white: #FFFFFF;
    --border: #E2E8F0;
    --success: #10B981;
    --radius-card: 14px;
    --radius-btn: 8px;
    --max-width: 1200px;
    --content-width: 800px;
    --header-height: 72px;
    --transition: 0.25s ease;
}

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

html {
    scroll-behavior: smooth;
    -webkit-text-size-adjust: 100%;
}

body {
    font-family: 'Inter', -apple-system, BlinkMacSystemFont, 'Segoe UI', sans-serif;
    font-size: 16px;
    line-height: 1.7;
    color: var(--dark-text);
    background: var(--white);
    -webkit-font-smoothing: antialiased;
    -moz-osx-font-smoothing: grayscale;
}

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

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

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

ul, ol {
    list-style: none;
}

/* --- Typography --- */
h1, h2, h3, h4, h5, h6 {
    color: var(--dark);
    line-height: 1.2;
    margin-bottom: 0.5em;
}

h1 {
    font-size: 3.25rem;
    font-weight: 800;
    letter-spacing: -0.02em;
}

h2 {
    font-size: 2.5rem;
    font-weight: 800;
    letter-spacing: -0.02em;
}

h3 {
    font-size: 1.5rem;
    font-weight: 700;
}

h4 {
    font-size: 1.25rem;
    font-weight: 700;
}

p {
    margin-bottom: 1rem;
}

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

.section {
    padding: 80px 0;
}

.section--cream {
    background: var(--cream);
}

.section--dark {
    background: var(--dark);
    color: var(--white);
}

.section--dark h2,
.section--dark h3 {
    color: var(--white);
}

.section-header {
    text-align: center;
    margin-bottom: 48px;
}

.section-header p {
    font-size: 1.125rem;
    color: var(--muted);
    max-width: 600px;
    margin: 0.5rem auto 0;
}

/* --- Buttons --- */
.btn {
    display: inline-flex;
    align-items: center;
    gap: 8px;
    padding: 14px 28px;
    border-radius: var(--radius-btn);
    font-weight: 600;
    font-size: 1rem;
    cursor: pointer;
    border: none;
    transition: all var(--transition);
    text-decoration: none;
}

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

.btn--primary:hover {
    background: var(--primary-hover);
    color: var(--white);
    transform: translateY(-1px);
    box-shadow: 0 4px 12px rgba(37, 99, 235, 0.3);
}

.btn--accent {
    background: var(--accent);
    color: var(--dark);
}

.btn--accent:hover {
    background: var(--accent-hover);
    color: var(--dark);
    transform: translateY(-1px);
    box-shadow: 0 4px 12px rgba(245, 158, 11, 0.3);
}

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

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

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

.btn--white:hover {
    background: var(--cream);
    color: var(--primary-hover);
    transform: translateY(-1px);
}

/* --- Header --- */
.site-header {
    background: var(--dark);
    position: sticky;
    top: 0;
    z-index: 1000;
    border-bottom: 1px solid rgba(255, 255, 255, 0.1);
}

.site-header .container {
    display: flex;
    align-items: center;
    justify-content: space-between;
    height: var(--header-height);
}

.site-logo img {
    height: 36px;
    width: auto;
}

.site-nav {
    display: flex;
    align-items: center;
    gap: 4px;
}

.site-nav a {
    color: rgba(255, 255, 255, 0.75);
    font-size: 0.9rem;
    font-weight: 500;
    padding: 8px 14px;
    border-radius: 6px;
    transition: all var(--transition);
    white-space: nowrap;
}

.site-nav a:hover,
.site-nav a.active {
    color: var(--white);
    background: rgba(255, 255, 255, 0.1);
}

.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: var(--white);
    border-radius: 2px;
    transition: all var(--transition);
}

/* --- Hero --- */
.hero {
    background: linear-gradient(135deg, var(--dark) 0%, #1a2744 100%);
    color: var(--white);
    padding: 100px 0 80px;
    text-align: center;
    position: relative;
    overflow: hidden;
}

.hero::before {
    content: '';
    position: absolute;
    top: -50%;
    left: -50%;
    width: 200%;
    height: 200%;
    background: radial-gradient(circle at 30% 50%, rgba(37, 99, 235, 0.15) 0%, transparent 50%),
                radial-gradient(circle at 70% 80%, rgba(245, 158, 11, 0.08) 0%, transparent 40%);
    pointer-events: none;
}

.hero .container {
    position: relative;
    z-index: 1;
}

.hero h1 {
    color: var(--white);
    max-width: 800px;
    margin: 0 auto 20px;
}

.hero .subtitle {
    font-size: 1.25rem;
    color: rgba(255, 255, 255, 0.8);
    max-width: 600px;
    margin: 0 auto 32px;
    line-height: 1.6;
}

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

.hero-badge {
    display: inline-flex;
    align-items: center;
    gap: 8px;
    background: rgba(245, 158, 11, 0.15);
    border: 1px solid rgba(245, 158, 11, 0.3);
    color: var(--accent);
    padding: 8px 16px;
    border-radius: 100px;
    font-size: 0.875rem;
    font-weight: 600;
    margin-bottom: 24px;
}

/* --- Stats Bar --- */
.stats-bar {
    background: var(--white);
    border-bottom: 1px solid var(--border);
    padding: 24px 0;
}

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

.stat-item {
    padding: 8px;
}

.stat-number {
    font-size: 2rem;
    font-weight: 800;
    color: var(--primary);
    line-height: 1;
}

.stat-label {
    font-size: 0.875rem;
    color: var(--muted);
    margin-top: 4px;
}

/* --- Silo Cards --- */
.silo-grid {
    display: grid;
    grid-template-columns: repeat(auto-fit, minmax(280px, 1fr));
    gap: 24px;
}

.silo-card {
    background: var(--white);
    border: 1px solid var(--border);
    border-radius: var(--radius-card);
    padding: 32px 24px;
    text-align: center;
    transition: all var(--transition);
    text-decoration: none;
    display: block;
}

.silo-card:hover {
    transform: translateY(-4px);
    box-shadow: 0 12px 40px rgba(0, 0, 0, 0.1);
    border-color: var(--primary);
}

.silo-card .icon {
    width: 56px;
    height: 56px;
    background: var(--primary-light);
    border-radius: 12px;
    display: flex;
    align-items: center;
    justify-content: center;
    margin: 0 auto 16px;
    font-size: 1.5rem;
}

.silo-card h3 {
    font-size: 1.125rem;
    margin-bottom: 8px;
}

.silo-card p {
    font-size: 0.9rem;
    color: var(--muted);
    margin-bottom: 12px;
}

.silo-card .card-link {
    font-size: 0.875rem;
    font-weight: 600;
    color: var(--primary);
    display: inline-flex;
    align-items: center;
    gap: 4px;
}

.silo-card:hover .card-link {
    gap: 8px;
}

/* --- Article Cards --- */
.article-grid {
    display: grid;
    grid-template-columns: repeat(auto-fill, minmax(340px, 1fr));
    gap: 24px;
}

.article-card {
    background: var(--white);
    border: 1px solid var(--border);
    border-radius: var(--radius-card);
    overflow: hidden;
    transition: all var(--transition);
    display: flex;
    flex-direction: column;
}

.article-card:hover {
    transform: translateY(-4px);
    box-shadow: 0 12px 40px rgba(0, 0, 0, 0.1);
}

.article-card__image {
    width: 100%;
    height: 200px;
    object-fit: cover;
    background: var(--cream-deep);
}

.article-card__body {
    padding: 24px;
    flex: 1;
    display: flex;
    flex-direction: column;
}

.article-card__meta {
    display: flex;
    align-items: center;
    gap: 12px;
    font-size: 0.8rem;
    color: var(--muted);
    margin-bottom: 12px;
}

.article-card__category {
    background: var(--primary-light);
    color: var(--primary);
    padding: 2px 10px;
    border-radius: 100px;
    font-weight: 600;
    font-size: 0.75rem;
    text-transform: uppercase;
    letter-spacing: 0.03em;
}

.article-card__title {
    font-size: 1.125rem;
    font-weight: 700;
    margin-bottom: 8px;
    line-height: 1.3;
}

.article-card__title a {
    color: var(--dark);
}

.article-card__title a:hover {
    color: var(--primary);
}

.article-card__excerpt {
    font-size: 0.9rem;
    color: var(--muted);
    margin-bottom: 16px;
    flex: 1;
}

.article-card__read-more {
    font-size: 0.875rem;
    font-weight: 600;
    color: var(--primary);
    display: inline-flex;
    align-items: center;
    gap: 4px;
}

/* --- About / Value Prop Section --- */
.value-grid {
    display: grid;
    grid-template-columns: repeat(auto-fit, minmax(250px, 1fr));
    gap: 32px;
}

.value-item {
    text-align: center;
    padding: 24px;
}

.value-item .icon {
    width: 48px;
    height: 48px;
    background: var(--primary-light);
    border-radius: 10px;
    display: flex;
    align-items: center;
    justify-content: center;
    margin: 0 auto 16px;
    font-size: 1.25rem;
}

.value-item h3 {
    font-size: 1.125rem;
    margin-bottom: 8px;
}

.value-item p {
    font-size: 0.9rem;
    color: var(--muted);
}

/* --- About Teaser --- */
.about-teaser {
    display: grid;
    grid-template-columns: auto 1fr;
    gap: 40px;
    align-items: center;
}

.about-teaser__avatar {
    width: 120px;
    height: 120px;
    border-radius: 50%;
    background: var(--primary-light);
    display: flex;
    align-items: center;
    justify-content: center;
    font-size: 2.5rem;
}

.about-teaser__content h3 {
    margin-bottom: 12px;
}

.about-teaser__content p {
    color: var(--muted);
    margin-bottom: 8px;
}

.about-teaser__badges {
    display: flex;
    gap: 8px;
    flex-wrap: wrap;
    margin-top: 16px;
}

.badge {
    display: inline-flex;
    align-items: center;
    gap: 4px;
    padding: 4px 12px;
    border-radius: 100px;
    font-size: 0.8rem;
    font-weight: 600;
    background: var(--primary-light);
    color: var(--primary);
}

/* --- CTA Section --- */
.cta-section {
    background: linear-gradient(135deg, var(--primary) 0%, var(--primary-hover) 100%);
    color: var(--white);
    text-align: center;
    padding: 80px 0;
}

.cta-section h2 {
    color: var(--white);
    margin-bottom: 16px;
}

.cta-section p {
    font-size: 1.125rem;
    opacity: 0.9;
    max-width: 500px;
    margin: 0 auto 32px;
}

/* --- Footer --- */
.site-footer {
    background: var(--dark);
    color: rgba(255, 255, 255, 0.7);
    padding: 64px 0 32px;
}

.footer-grid {
    display: grid;
    grid-template-columns: 2fr 1fr 1fr 1fr;
    gap: 40px;
    margin-bottom: 48px;
}

.footer-brand p {
    font-size: 0.9rem;
    margin-top: 16px;
    line-height: 1.6;
}

.footer-col h4 {
    color: var(--white);
    font-size: 0.9rem;
    text-transform: uppercase;
    letter-spacing: 0.05em;
    margin-bottom: 16px;
}

.footer-col ul {
    display: flex;
    flex-direction: column;
    gap: 10px;
}

.footer-col a {
    color: rgba(255, 255, 255, 0.6);
    font-size: 0.875rem;
    transition: color var(--transition);
}

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

.footer-bottom {
    border-top: 1px solid rgba(255, 255, 255, 0.1);
    padding-top: 24px;
    display: flex;
    justify-content: space-between;
    align-items: center;
    font-size: 0.8rem;
}

.footer-bottom a {
    color: rgba(255, 255, 255, 0.5);
}

/* --- Breadcrumb --- */
.breadcrumb {
    padding: 16px 0;
    font-size: 0.875rem;
}

.breadcrumb ol {
    display: flex;
    align-items: center;
    gap: 8px;
    flex-wrap: wrap;
}

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

.breadcrumb li + li::before {
    content: '›';
    color: var(--muted);
}

.breadcrumb a {
    color: var(--muted);
}

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

.breadcrumb .current {
    color: var(--dark-text);
    font-weight: 500;
}

/* --- Silo Hero (for index pages) --- */
.silo-hero {
    background: linear-gradient(135deg, var(--dark) 0%, #1a2744 100%);
    color: var(--white);
    padding: 60px 0 48px;
}

.silo-hero h1 {
    color: var(--white);
    font-size: 2.5rem;
    margin-bottom: 12px;
}

.silo-hero p {
    font-size: 1.125rem;
    color: rgba(255, 255, 255, 0.8);
    max-width: 600px;
}

/* --- Article Page Styles --- */
.article-hero {
    background: var(--cream);
    padding: 40px 0;
    border-bottom: 1px solid var(--border);
}

.article-hero h1 {
    font-size: 2.5rem;
    max-width: var(--content-width);
}

.article-meta {
    display: flex;
    align-items: center;
    gap: 16px;
    margin-top: 16px;
    font-size: 0.875rem;
    color: var(--muted);
}

.article-meta span {
    display: inline-flex;
    align-items: center;
    gap: 4px;
}

/* --- Responsive --- */
@media (max-width: 1024px) {
    .footer-grid {
        grid-template-columns: 1fr 1fr;
    }
}

@media (max-width: 768px) {
    h1 { font-size: 2.25rem; }
    h2 { font-size: 1.75rem; }

    .section { padding: 56px 0; }

    .hero { padding: 64px 0 56px; }
    .hero .subtitle { font-size: 1.1rem; }

    /* Mobile nav */
    .nav-toggle {
        display: flex;
    }

    .site-nav {
        position: fixed;
        top: var(--header-height);
        left: 0;
        right: 0;
        background: var(--dark);
        flex-direction: column;
        padding: 16px 24px;
        gap: 4px;
        transform: translateY(-100%);
        opacity: 0;
        pointer-events: none;
        transition: all 0.3s ease;
        border-bottom: 1px solid rgba(255, 255, 255, 0.1);
    }

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

    .site-nav a {
        padding: 12px 16px;
        width: 100%;
    }

    /* Grids */
    .stats-grid {
        grid-template-columns: repeat(2, 1fr);
    }

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

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

    .footer-grid {
        grid-template-columns: 1fr;
        gap: 32px;
    }

    .footer-bottom {
        flex-direction: column;
        gap: 8px;
        text-align: center;
    }

    .about-teaser {
        grid-template-columns: 1fr;
        text-align: center;
    }

    .about-teaser__avatar {
        margin: 0 auto;
    }

    .about-teaser__badges {
        justify-content: center;
    }

    .silo-hero h1 {
        font-size: 2rem;
    }

    .article-hero h1 {
        font-size: 2rem;
    }
}

@media (max-width: 480px) {
    h1 { font-size: 1.75rem; }
    h2 { font-size: 1.5rem; }

    .container { padding: 0 16px; }

    .hero { padding: 48px 0 40px; }

    .btn { padding: 12px 24px; font-size: 0.9rem; }

    .stats-grid { gap: 16px; }
    .stat-number { font-size: 1.5rem; }
}