:root {
    --white: #ffffff;
    --off-white: #f8fafc;
    --blue-primary: #0066ff;
    --blue-dark: #0052cc;
    --blue-light: #e6f0ff;
    --green-primary: #00c853;
    --green-dark: #00a844;
    --green-light: #e6fff0;
    --navy: #0a1628;
    --gray-100: #f1f5f9;
    --gray-200: #e2e8f0;
    --gray-400: #94a3b8;
    --gray-600: #475569;
    --gray-800: #1e293b;
    --gradient-hero: linear-gradient(135deg, #0066ff 0%, #00c853 100%);
    --gradient-cta: linear-gradient(135deg, #00c853 0%, #00e676 100%);
    --gradient-blue: linear-gradient(135deg, #0066ff 0%, #0099ff 100%);
    --gradient-math: linear-gradient(135deg, #6366f1 0%, #8b5cf6 100%);
    --gradient-physics: linear-gradient(135deg, #f59e0b 0%, #fbbf24 100%);
    --gradient-chemistry: linear-gradient(135deg, #ef4444 0%, #f87171 100%);
    --shadow-soft: 0 4px 20px rgba(0, 102, 255, 0.1);
    --shadow-medium: 0 8px 30px rgba(0, 102, 255, 0.15);
    --shadow-strong: 0 15px 50px rgba(0, 102, 255, 0.2);
}

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

html {
    scroll-behavior: smooth;
}

body {
    font-family: 'Plus Jakarta Sans', sans-serif;
    background: var(--white);
    color: var(--gray-800);
    overflow-x: hidden;
    line-height: 1.6;
}

.footer {
    background: var(--navy);
    padding: 4rem 2rem 2rem;
    color: var(--white);
}

.footer-container {
    max-width: 1400px;
    margin: 0 auto;
}

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

.footer-brand .logo {
    margin-bottom: 1rem;
}

.footer-brand .logo-text {
    color: var(--white);
}

.footer-desc {
    color: var(--gray-400);
    font-size: 0.95rem;
    line-height: 1.7;
    margin-bottom: 1.5rem;
}

.social-links {
    display: flex;
    gap: 1rem;
}

.social-link {
    width: 45px;
    height: 45px;
    background: rgba(255, 255, 255, 0.1);
    border-radius: 12px;
    display: flex;
    align-items: center;
    justify-content: center;
    color: var(--white);
    font-size: 1.2rem;
    transition: all 0.3s ease;
}

.social-link:hover {
    background: var(--blue-primary);
    transform: translateY(-3px);
}

.footer-title {
    font-family: 'Syne', sans-serif;
    font-size: 1.1rem;
    font-weight: 700;
    margin-bottom: 1.5rem;
    color: var(--white);
}

.footer-links {
    list-style: none;
}

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

.footer-links a {
    color: var(--gray-400);
    text-decoration: none;
    font-size: 0.95rem;
    transition: color 0.3s ease;
}

.footer-links a:hover {
    color: var(--green-primary);
}

.footer-bottom {
    padding-top: 2rem;
    border-top: 1px solid rgba(255, 255, 255, 0.1);
    display: flex;
    justify-content: space-between;
    align-items: center;
    flex-wrap: wrap;
    gap: 1rem;
}

.footer-copyright {
    color: var(--gray-400);
    font-size: 0.9rem;
}

.footer-legal {
    display: flex;
    gap: 2rem;
}

.footer-legal a {
    color: var(--gray-400);
    text-decoration: none;
    font-size: 0.9rem;
    transition: color 0.3s ease;
}

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