:root {
    --primary-bg: #0a0e1b;
    --secondary-bg: #141b2d;
    --accent-gold: #c9a227;
    --accent-cyan: #4cc9f0;
    --text-primary: #e0e6ed;
    --text-secondary: #94a3b8;
    --gradient-hero: linear-gradient(135deg, #0a0e1b 0%, #161a29 100%);
    --gradient-gold: linear-gradient(135deg, #f1c40f 0%, #c9a227 100%);
    --shadow-soft: 0 10px 30px rgba(0,0,0,0.5);
    --glass-bg: rgba(255, 255, 255, 0.05);
    --glass-border: rgba(255, 255, 255, 0.1);
}

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

body {
    background-color: var(--primary-bg);
    color: var(--text-primary);
    font-family: 'Outfit', sans-serif;
    line-height: 1.6;
    overflow-x: hidden;
    scroll-behavior: smooth;
    -webkit-font-smoothing: antialiased;
}

h1, h2, h3 {
    font-weight: 800;
    line-height: 1.2;
    margin-bottom: 1.5rem;
}

a {
    text-decoration: none;
    color: inherit;
    transition: all 0.3s ease;
}

ul {
    list-style: none;
}

/* Container */
.container {
    max-width: 1200px;
    margin: 0 auto;
    padding: 0 2rem;
}

.text-center { text-align: center; }
.max-600 { max-width: 600px; margin-left: auto; margin-right: auto; }

/* Navigation */
#main-nav {
    position: fixed;
    top: 0;
    width: 100%;
    z-index: 1000;
    display: flex;
    justify-content: space-between;
    align-items: center;
    padding: 1.5rem 4rem;
    background: rgba(10, 14, 27, 0.8);
    backdrop-filter: blur(10px);
    border-bottom: 1px solid var(--glass-border);
    transition: all 0.4s ease;
}

#main-nav.scrolled {
    padding: 1rem 4rem;
    box-shadow: var(--shadow-soft);
}

.logo {
    font-size: 1.8rem;
    font-weight: 800;
    letter-spacing: -1px;
}

.logo span {
    color: var(--accent-gold);
}

.nav-links {
    display: flex;
    gap: 2.5rem;
}

.nav-links a {
    font-weight: 500;
    font-size: 0.95rem;
    text-transform: uppercase;
    letter-spacing: 1px;
    color: var(--text-secondary);
}

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

/* Hero Section */
#hero {
    height: 100vh;
    display: flex;
    align-items: center;
    justify-content: center;
    position: relative;
    background-image: url('assets/hero.png');
    background-size: cover;
    background-position: center;
    background-attachment: fixed;
}

.hero-overlay {
    position: absolute;
    inset: 0;
    background: radial-gradient(circle at center, rgba(10, 14, 27, 0.4) 0%, rgba(10, 14, 27, 0.9) 100%);
}

.hero-content {
    position: relative;
    z-index: 2;
    text-align: center;
    max-width: 900px;
    padding: 0 2rem;
}

#hero h1 {
    font-size: clamp(3rem, 10vw, 5.5rem);
    margin-bottom: 1rem;
    text-shadow: 0 5px 25px rgba(0,0,0,0.5);
}

#hero h1 span {
    background: var(--gradient-gold);
    -webkit-background-clip: text;
    -webkit-text-fill-color: transparent;
}

.subtitle {
    font-size: clamp(1.1rem, 3vw, 1.5rem);
    color: var(--text-secondary);
    max-width: 700px;
    margin: 0 auto;
    font-weight: 300;
}

/* Animations */
.fade-in {
    opacity: 0;
    transform: translateY(30px);
    animation: fadeInUp 1s forwards;
}

.fade-in-delayed {
    opacity: 0;
    transform: translateY(30px);
    animation: fadeInUp 1s 0.3s forwards;
}

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

/* Content Sections */
.content-section {
    padding: 8rem 0;
    position: relative;
}

.alt-bg {
    background-color: var(--secondary-bg);
}

.section-tag {
    display: inline-block;
    padding: 0.4rem 1rem;
    background: rgba(201, 162, 39, 0.15);
    color: var(--accent-gold);
    border-radius: 30px;
    font-size: 0.8rem;
    font-weight: 600;
    text-transform: uppercase;
    letter-spacing: 2px;
    margin-bottom: 1.5rem;
}

.grid {
    display: grid;
    grid-template-columns: 1fr 1fr;
    gap: 4rem;
    align-items: center;
}

.box-visual {
    background: var(--glass-bg);
    backdrop-filter: blur(5px);
    border: 1px solid var(--glass-border);
    border-radius: 20px;
    padding: 3rem;
    height: 400px;
    display: flex;
    flex-direction: column;
    justify-content: center;
    align-items: center;
    box-shadow: var(--shadow-soft);
}

.hilbert-quote {
    margin-top: 2rem;
    padding-left: 1.5rem;
    border-left: 4px solid var(--accent-gold);
    font-family: 'Roboto Mono', monospace;
    font-size: 1.1rem;
    color: var(--text-primary);
}

.hilbert-quote span {
    display: block;
    font-size: 0.9rem;
    color: var(--text-secondary);
    margin-top: 0.5rem;
}

/* Gödel Numbering Demo */
.godel-numbering-demo {
    margin-top: 3rem;
    background: var(--primary-bg);
    border-radius: 20px;
    padding: 3rem;
    border: 1px solid var(--glass-border);
}

.mapping-container {
    display: flex;
    justify-content: center;
    gap: 2rem;
    flex-wrap: wrap;
    margin-bottom: 2rem;
}

.mapping-item {
    background: rgba(255,255,255,0.03);
    padding: 1.5rem;
    border-radius: 12px;
    min-width: 120px;
    text-align: center;
    border: 1px solid transparent;
    transition: all 0.3s;
}

.mapping-item:hover {
    border-color: var(--accent-cyan);
    transform: translateY(-5px);
}

.mapping-item .sym {
    display: block;
    font-size: 2rem;
    color: var(--accent-cyan);
    font-family: 'Roboto Mono', monospace;
}

.mapping-item .arrow {
    display: block;
    margin: 0.5rem 0;
    color: var(--text-secondary);
}

.mapping-item .num {
    display: block;
    font-size: 1.5rem;
    font-weight: 800;
    color: var(--accent-gold);
}

/* Theorem Cards */
.theorems-grid {
    display: grid;
    grid-template-columns: 1fr 1fr;
    gap: 3rem;
}

.theorem-card {
    background: var(--glass-bg);
    border: 1px solid var(--glass-border);
    border-radius: 24px;
    padding: 4rem 3rem;
    position: relative;
    overflow: hidden;
    transition: all 0.5s cubic-bezier(0.175, 0.885, 0.32, 1.275);
}

.theorem-card:hover {
    transform: translateY(-10px);
    background: rgba(255,255,255,0.08);
    border-color: var(--accent-gold);
}

.card-num {
    position: absolute;
    top: -20px;
    right: -20px;
    font-size: 10rem;
    font-weight: 900;
    color: rgba(255,255,255,0.03);
    pointer-events: none;
}

.theorem-card h3 {
    color: var(--accent-gold);
    font-size: 1.8rem;
    margin-bottom: 1.5rem;
}

.definition {
    font-size: 1.1rem;
    margin-bottom: 2rem;
}

.lesson {
    background: rgba(0,0,0,0.2);
    padding: 1.2rem;
    border-radius: 12px;
    border-left: 3px solid var(--accent-cyan);
    font-size: 0.95rem;
}

/* Interactive Paradox */
.paradox-interactive {
    margin-top: 4rem;
    max-width: 800px;
    margin-left: auto;
    margin-right: auto;
}

#paradox-box {
    background: var(--gradient-hero);
    border-radius: 24px;
    padding: 4rem;
    text-align: center;
    border: 1px solid var(--accent-cyan);
    box-shadow: 0 0 30px rgba(76, 201, 240, 0.1);
    margin-bottom: 3rem;
}

#paradox-text {
    font-size: 1.8rem;
    font-weight: 600;
    margin-bottom: 2rem;
    font-family: 'Roboto Mono', monospace;
}

.choices {
    display: flex;
    justify-content: center;
    gap: 1.5rem;
}

.choices button {
    padding: 1rem 2.5rem;
    border-radius: 12px;
    border: none;
    background: var(--accent-cyan);
    color: #000;
    font-weight: 800;
    cursor: pointer;
    transition: all 0.3s;
}

.choices button:hover {
    transform: scale(1.05);
    box-shadow: 0 0 20px var(--accent-cyan);
}

.feedback {
    margin-top: 2rem;
    min-height: 1.5rem;
    font-weight: 600;
    color: var(--accent-gold);
}

.analogy {
    padding: 2.5rem;
    background: rgba(255,255,255,0.02);
    border-radius: 16px;
}

.analogy h4 {
    margin-bottom: 1rem;
    color: var(--accent-cyan);
}

/* Footer */
footer {
    padding: 4rem 0 2rem;
    border-top: 1px solid var(--glass-border);
}

.footer-content {
    display: flex;
    justify-content: space-between;
    align-items: center;
    margin-bottom: 3rem;
}

.copyright {
    text-align: center;
    font-size: 0.8rem;
    color: var(--text-secondary);
}

/* Animation triggers */
[data-aos] {
    opacity: 0;
    transition: all 0.8s ease;
}

[data-aos="fade-right"] { transform: translateX(-50px); }
[data-aos="fade-left"] { transform: translateX(50px); }
[data-aos="flip-left"] { transform: perspective(1000px) rotateY(-30deg); }
[data-aos="flip-right"] { transform: perspective(1000px) rotateY(30deg); }

.animate {
    opacity: 1 !important;
    transform: translate(0) rotateY(0) !important;
}

/* Responsive */
@media (max-width: 768px) {
    #main-nav { padding: 1rem 2rem; }
    .nav-links { display: none; }
    .grid { grid-template-columns: 1fr; gap: 2rem; }
    .theorems-grid { grid-template-columns: 1fr; }
    #hero h1 { font-size: 3.5rem; }
    .theorem-card { padding: 3rem 2rem; }
}

/* Custom Cogs Animation */
.logic-machine {
    position: relative;
    width: 200px;
    height: 150px;
}

.cog {
    width: 60px;
    height: 60px;
    border: 5px solid var(--accent-gold);
    border-radius: 50%;
    position: absolute;
    animation: rotate 4s linear infinite;
}

.cog::after {
    content: '';
    position: absolute;
    top: -10px; left: 22px; width: 6px; height: 10px; background: var(--accent-gold);
    box-shadow: 0 70px var(--accent-gold), -25px 35px var(--accent-gold), 25px 35px var(--accent-gold);
}

.cog:nth-child(2) { top: 40px; left: 55px; animation-direction: reverse; width: 80px; height: 80px;}
.cog:nth-child(3) { top: 10px; left: 110px; }

@keyframes rotate { from { transform: rotate(0deg); } to { transform: rotate(360deg); } }