/* ── Variables ── */
:root {
    --primary: #6366f1;
    --primary-dark: #4f46e5;
    --primary-light: #818cf8;
    --accent: #22d3ee;
    --bg-dark: #0f0f1a;
    --bg-card: #1a1a2e;
    --bg-card-hover: #252542;
    --text-primary: #ffffff;
    --text-secondary: #a1a1aa;
    --text-muted: #71717a;
    --gradient-1: linear-gradient(135deg, #6366f1 0%, #8b5cf6 50%, #d946ef 100%);
    --gradient-2: linear-gradient(135deg, #22d3ee 0%, #6366f1 100%);
    --shadow-glow: 0 0 60px rgba(99, 102, 241, 0.3);
}

/* ── Reset ── */
* {
    margin: 0;
    padding: 0;
    box-sizing: border-box;
}

html {
    scroll-behavior: smooth;
}

body {
    font-family: 'Inter', -apple-system, BlinkMacSystemFont, sans-serif;
    background: var(--bg-dark);
    color: var(--text-primary);
    line-height: 1.6;
    overflow-x: hidden;
}

/* ── Background ── */
.bg-gradient {
    position: fixed;
    top: 0;
    left: 0;
    right: 0;
    bottom: 0;
    background:
        radial-gradient(ellipse 80% 50% at 50% -20%, rgba(99, 102, 241, 0.15) 0%, transparent 50%),
        radial-gradient(ellipse 60% 40% at 100% 50%, rgba(139, 92, 246, 0.1) 0%, transparent 50%),
        radial-gradient(ellipse 60% 40% at 0% 80%, rgba(34, 211, 238, 0.08) 0%, transparent 50%);
    pointer-events: none;
    z-index: -1;
}

/* ── Navigation ── */
nav {
    position: fixed;
    top: 0;
    left: 0;
    right: 0;
    z-index: 100;
    padding: 1.25rem 2rem;
    background: rgba(15, 15, 26, 0.8);
    backdrop-filter: blur(20px);
    border-bottom: 1px solid rgba(255, 255, 255, 0.05);
    transition: all 0.3s ease;
}

nav.scrolled {
    padding: 0.75rem 2rem;
    background: rgba(15, 15, 26, 0.95);
}

.nav-container {
    max-width: 1200px;
    margin: 0 auto;
    display: flex;
    justify-content: space-between;
    align-items: center;
}

.logo {
    font-size: 1.5rem;
    font-weight: 800;
    background: var(--gradient-1);
    -webkit-background-clip: text;
    -webkit-text-fill-color: transparent;
    background-clip: text;
    letter-spacing: -0.5px;
    text-decoration: none;
}

.nav-links {
    display: flex;
    gap: 2.5rem;
    list-style: none;
}

.nav-links a {
    color: var(--text-secondary);
    text-decoration: none;
    font-size: 0.9rem;
    font-weight: 500;
    transition: color 0.2s;
}

.nav-links a:hover,
.nav-links a.active {
    color: var(--text-primary);
}

.nav-cta {
    background: var(--gradient-1);
    color: white;
    padding: 0.6rem 1.5rem;
    border-radius: 8px;
    text-decoration: none;
    font-weight: 600;
    font-size: 0.9rem;
    transition: transform 0.2s, box-shadow 0.2s;
}

.nav-cta:hover {
    transform: translateY(-2px);
    box-shadow: 0 10px 30px rgba(99, 102, 241, 0.3);
}

/* ── Hamburger menu ── */
.hamburger {
    display: none;
    flex-direction: column;
    justify-content: center;
    gap: 5px;
    background: none;
    border: none;
    cursor: pointer;
    padding: 4px;
    z-index: 101;
}

.hamburger span {
    display: block;
    width: 22px;
    height: 2px;
    background: var(--text-secondary);
    border-radius: 2px;
    transition: all 0.3s ease;
}

.hamburger.open span:nth-child(1) {
    transform: rotate(45deg) translate(5px, 5px);
}

.hamburger.open span:nth-child(2) {
    opacity: 0;
}

.hamburger.open span:nth-child(3) {
    transform: rotate(-45deg) translate(5px, -5px);
}

.mobile-menu {
    display: none;
    position: fixed;
    top: 0;
    left: 0;
    right: 0;
    bottom: 0;
    background: rgba(15, 15, 26, 0.98);
    backdrop-filter: blur(20px);
    z-index: 99;
    flex-direction: column;
    align-items: center;
    justify-content: center;
    gap: 2rem;
}

.mobile-menu.open {
    display: flex;
}

.mobile-menu a {
    color: var(--text-primary);
    text-decoration: none;
    font-size: 1.25rem;
    font-weight: 500;
    transition: color 0.2s;
}

.mobile-menu a:hover {
    color: var(--primary-light);
}

.mobile-menu a.active {
    color: var(--primary-light);
}

/* ── Section common ── */
.section-header {
    text-align: center;
    max-width: 700px;
    margin: 0 auto 3rem;
}

.section-label {
    color: var(--primary-light);
    font-size: 0.85rem;
    font-weight: 600;
    text-transform: uppercase;
    letter-spacing: 2px;
    margin-bottom: 1rem;
}

.section-title {
    font-size: clamp(2rem, 4vw, 3rem);
    font-weight: 700;
    margin-bottom: 1rem;
    letter-spacing: -1px;
}

.section-subtitle {
    color: var(--text-secondary);
    font-size: 1.1rem;
}

/* ── Buttons ── */
.btn-primary {
    background: var(--gradient-1);
    color: white;
    padding: 1rem 2.5rem;
    border-radius: 12px;
    text-decoration: none;
    font-weight: 600;
    font-size: 1rem;
    display: inline-flex;
    align-items: center;
    gap: 0.5rem;
    transition: transform 0.2s, box-shadow 0.2s;
    border: none;
    cursor: pointer;
}

.btn-primary:hover {
    transform: translateY(-3px);
    box-shadow: var(--shadow-glow);
}

.btn-secondary {
    background: transparent;
    color: var(--text-primary);
    padding: 1rem 2.5rem;
    border-radius: 12px;
    text-decoration: none;
    font-weight: 600;
    font-size: 1rem;
    border: 1px solid rgba(255, 255, 255, 0.15);
    transition: all 0.2s;
    display: inline-flex;
    align-items: center;
    gap: 0.5rem;
}

.btn-secondary:hover {
    background: rgba(255, 255, 255, 0.05);
    border-color: rgba(255, 255, 255, 0.25);
}

/* ── Animations ── */
@keyframes fadeInUp {
    from {
        opacity: 0;
        transform: translateY(20px);
    }
    to {
        opacity: 1;
        transform: translateY(0);
    }
}

.animate-on-scroll {
    opacity: 0;
    transform: translateY(30px);
    transition: all 0.6s ease;
}

.animate-on-scroll.visible {
    opacity: 1;
    transform: translateY(0);
}

/* ── 4-column footer ── */
.site-footer {
    padding: 4rem 2rem 2rem;
    border-top: 1px solid rgba(255, 255, 255, 0.05);
}

.footer-inner {
    max-width: 1200px;
    margin: 0 auto;
}

.footer-grid {
    display: grid;
    grid-template-columns: 1.5fr 1fr 1fr 1fr;
    gap: 3rem;
    margin-bottom: 3rem;
}

.footer-col h4 {
    font-size: 0.85rem;
    font-weight: 600;
    text-transform: uppercase;
    letter-spacing: 1px;
    color: var(--text-primary);
    margin-bottom: 1rem;
}

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

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

.footer-col ul a {
    color: var(--text-secondary);
    text-decoration: none;
    font-size: 0.9rem;
    transition: color 0.2s;
}

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

.footer-brand-logo {
    font-size: 1.25rem;
    font-weight: 700;
    background: var(--gradient-1);
    -webkit-background-clip: text;
    -webkit-text-fill-color: transparent;
    background-clip: text;
    margin-bottom: 0.75rem;
}

.footer-brand-tagline {
    color: var(--text-secondary);
    font-size: 0.9rem;
    line-height: 1.6;
    margin-bottom: 1rem;
}

.footer-brand-copy {
    color: var(--text-muted);
    font-size: 0.85rem;
}

.footer-bottom {
    display: flex;
    justify-content: space-between;
    align-items: center;
    padding-top: 2rem;
    border-top: 1px solid rgba(255, 255, 255, 0.05);
    flex-wrap: wrap;
    gap: 1rem;
}

.footer-bottom-links {
    display: flex;
    gap: 1.5rem;
}

.footer-bottom-links a {
    color: var(--text-muted);
    text-decoration: none;
    font-size: 0.85rem;
    transition: color 0.2s;
}

.footer-bottom-links a:hover {
    color: var(--text-secondary);
}

.footer-bottom-message {
    color: var(--text-muted);
    font-size: 0.85rem;
    font-style: italic;
}

/* ── Responsive ── */
@media (max-width: 768px) {
    .nav-links {
        display: none;
    }

    .hamburger {
        display: flex;
    }

    .footer-grid {
        grid-template-columns: 1fr;
        gap: 2rem;
    }

    .btn-primary, .btn-secondary {
        width: 100%;
        max-width: 280px;
        justify-content: center;
    }
}