:root {
    --bg-dark: #0f172a;
    --bg-card: #1e293b;
    --text-primary: #f8fafc;
    --text-secondary: #94a3b8;
    --accent: #3b82f6;
    --accent-hover: #2563eb;
    --accent-glow: rgba(59, 130, 246, 0.5);
}

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

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

/* Typography & Ergonomics */
h1, h2, h3 {
    font-weight: 800;
    letter-spacing: -0.02em;
    margin-bottom: 1rem;
}

h1 { font-size: 3.5rem; line-height: 1.2; }
h2 { font-size: 2.5rem; }
h3 { font-size: 1.5rem; }
p { font-size: 1.125rem; color: var(--text-secondary); margin-bottom: 1.5rem; }

/* Navbar */
.navbar {
    display: flex;
    justify-content: space-between;
    align-items: center;
    padding: 1.5rem 5%;
    background: rgba(15, 23, 42, 0.9);
    backdrop-filter: blur(10px);
    position: fixed;
    top: 0;
    width: 100%;
    z-index: 1000;
    transition: transform 0.3s ease;
}

.logo {
    font-size: 1.5rem;
    font-weight: 800;
    color: var(--text-primary);
}

nav ul {
    list-style: none;
    display: flex;
    gap: 2rem;
    align-items: center;
}

nav a {
    color: var(--text-primary);
    text-decoration: none;
    font-weight: 600;
    transition: color 0.2s ease;
}

nav a:hover {
    color: var(--accent);
}

/* Buttons */
.btn-primary {
    background-color: var(--accent);
    color: white;
    border: none;
    padding: 0.75rem 1.5rem;
    border-radius: 0.5rem;
    font-weight: 600;
    font-size: 1rem;
    cursor: pointer;
    transition: all 0.3s cubic-bezier(0.4, 0, 0.2, 1);
    box-shadow: 0 4px 6px -1px var(--accent-glow);
}

.btn-primary:hover {
    background-color: var(--accent-hover);
    transform: translateY(-2px);
    box-shadow: 0 10px 15px -3px var(--accent-glow);
}

.btn-primary.large {
    padding: 1rem 2rem;
    font-size: 1.25rem;
}

/* Sections */
main {
    margin-top: 5rem;
}

section {
    padding: 6rem 5%;
    max-width: 1200px;
    margin: 0 auto;
}

.hero {
    text-align: center;
    padding-top: 10rem;
    padding-bottom: 8rem;
}

.hero p {
    max-width: 800px;
    margin: 0 auto 3rem auto;
}

/* Grid & Cards */
.grid {
    display: grid;
    grid-template-columns: repeat(auto-fit, minmax(280px, 1fr));
    gap: 2rem;
    margin-top: 3rem;
}

.card {
    background: var(--bg-card);
    padding: 2rem;
    border-radius: 1rem;
    border: 1px solid rgba(255,255,255,0.05);
    transition: transform 0.3s ease, box-shadow 0.3s ease, border-color 0.3s ease;
}

.card:hover {
    transform: translateY(-5px);
    box-shadow: 0 20px 25px -5px rgba(0,0,0,0.5);
    border-color: rgba(255,255,255,0.1);
}

.card h3 {
    color: var(--accent);
}

/* AI Visualizer */
.ai-section {
    text-align: center;
}

.ai-visual {
    position: relative;
    width: 200px;
    height: 200px;
    margin: 4rem auto;
    display: flex;
    justify-content: center;
    align-items: center;
}

.core-node {
    width: 80px;
    height: 80px;
    background: var(--accent);
    border-radius: 50%;
    display: flex;
    justify-content: center;
    align-items: center;
    font-weight: 800;
    font-size: 1.5rem;
    z-index: 10;
    box-shadow: 0 0 30px var(--accent-glow);
}

.pulse-ring {
    position: absolute;
    width: 100%;
    height: 100%;
    border: 2px solid var(--accent);
    border-radius: 50%;
    animation: pulse 3s cubic-bezier(0.215, 0.61, 0.355, 1) infinite;
    opacity: 0;
}

.pulse-ring.delay {
    animation-delay: 1.5s;
}

@keyframes pulse {
    0% { transform: scale(0.5); opacity: 0; }
    50% { opacity: 0.5; }
    100% { transform: scale(1.5); opacity: 0; }
}

/* Footer */
footer {
    text-align: center;
    padding: 3rem;
    border-top: 1px solid rgba(255,255,255,0.05);
    color: var(--text-secondary);
}

/* Micro-animations Classes */
.fade-in {
    opacity: 0;
    transform: scale(0.95);
    transition: opacity 0.8s ease-out, transform 0.8s ease-out;
}

.fade-in.visible {
    opacity: 1;
    transform: scale(1);
}

.slide-up {
    opacity: 0;
    transform: translateY(30px);
    transition: opacity 0.8s ease-out, transform 0.8s ease-out;
}

.slide-up.visible {
    opacity: 1;
    transform: translateY(0);
}

.delay-1 { transition-delay: 0.1s; }
.delay-2 { transition-delay: 0.2s; }
.delay-3 { transition-delay: 0.3s; }
.delay-4 { transition-delay: 0.4s; }