:root {
    --bg-color: #030305;
    --card-bg: rgba(255, 255, 255, 0.03);
    --border-color: rgba(255, 255, 255, 0.08);
    --text-primary: #ffffff;
    --text-secondary: #c0c0c8;
    --accent-purple: #a855f7;
    --accent-blue: #3b82f6;
    --accent-gold: #eab308;
    --accent-red: #ef4444;
    --font-main: 'Inter', sans-serif;
    --font-mono: 'Fira Code', monospace;
    --transition: all 0.3s cubic-bezier(0.4, 0, 0.2, 1);
}

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

html {
    scroll-behavior: smooth;
}

body {
    background-color: var(--bg-color);
    color: var(--text-primary);
    font-family: var(--font-main);
    line-height: 1.6;
    overflow-x: hidden;
}

/* Background Stars */
.stars-container {
    position: fixed;
    top: 0;
    left: 0;
    width: 100%;
    height: 100%;
    z-index: -1;
    pointer-events: none;
    background: radial-gradient(circle at 50% 50%, #0d0d15 0%, #030305 100%);
}

.star {
    position: absolute;
    background: white;
    border-radius: 50%;
}

@keyframes twinkle {

    0%,
    100% {
        opacity: 0.2;
        transform: scale(1);
    }

    50% {
        opacity: 0.8;
        transform: scale(1.3);
    }
}

/* Typography */
h1,
h2,
h3 {
    font-weight: 700;
    letter-spacing: -0.02em;
}

h2 {
    font-size: 2.2rem;
    margin-bottom: 1.5rem;
    background: linear-gradient(to right, #fff, #9ca3af);
    -webkit-background-clip: text;
    background-clip: text;
    -webkit-text-fill-color: transparent;
}

p {
    margin-bottom: 1rem;
    color: var(--text-secondary);
    font-size: 1.1rem;
}

strong {
    color: var(--text-primary);
    font-weight: 600;
}

code {
    font-family: var(--font-mono);
    background: rgba(255, 255, 255, 0.1);
    padding: 0.2rem 0.4rem;
    border-radius: 4px;
    font-size: 0.9em;
    color: var(--accent-blue);
}

/* Header & Navbar */
header {
    width: 100%;
    padding: 1.5rem;
    position: fixed;
    top: 0;
    z-index: 1000;
}

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

.logo-at {
    font-size: 1.5rem;
    font-weight: 800;
    letter-spacing: -1px;
    color: var(--accent-blue);
    filter: drop-shadow(0 0 8px rgba(59, 130, 246, 0.5));
    transition: var(--transition);
    cursor: pointer;
    text-decoration: none;
}

.nav-links {
    display: flex;
    list-style: none;
    background: rgba(15, 15, 20, 0.6);
    backdrop-filter: blur(12px);
    padding: 0.4rem;
    border-radius: 50px;
    border: 1px solid var(--border-color);
    box-shadow: 0 8px 32px rgba(0, 0, 0, 0.4);
}

.nav-links li a {
    text-decoration: none;
    color: var(--text-secondary);
    padding: 0.6rem 1.2rem;
    transition: var(--transition);
    font-size: 0.85rem;
    font-weight: 500;
}

.nav-links li a:hover {
    color: var(--text-primary);
    transform: translateY(-1px);
}

.nav-connect {
    background: rgba(255, 255, 255, 0.08);
    border-radius: 20px;
    color: var(--text-primary) !important;
}

/* Main Layout */
.main-container {
    max-width: 900px;
    margin: 0 auto;
    padding: 0 2rem;
}

/* Hero Section */
.hero {
    height: 90vh;
    display: flex;
    justify-content: center;
    align-items: center;
    text-align: center;
    position: relative;
    padding-top: 4rem;
}

.badge {
    display: inline-block;
    padding: 0.5rem 1.2rem;
    background: rgba(168, 85, 247, 0.1);
    border: 1px solid rgba(168, 85, 247, 0.2);
    color: var(--accent-purple);
    border-radius: 50px;
    font-size: 0.85rem;
    font-weight: 600;
    margin-bottom: 2rem;
    text-transform: uppercase;
    letter-spacing: 0.1em;
}

.hero-title {
    font-size: 4.5rem;
    line-height: 1;
    margin-bottom: 1.5rem;
}

.accent-text {
    display: block;
    margin-top: 0.5rem;
    color: var(--accent-blue);
    font-weight: 800;
}

.hero-subtitle {
    font-size: 1.8rem;
    color: var(--text-secondary);
    font-weight: 300;
    max-width: 700px;
    margin: 0 auto;
}

/* Content Sections */
.content-section {
    padding: 4rem 0;
}

.glass-card {
    background: var(--card-bg);
    border: 1px solid var(--border-color);
    padding: 3rem;
    border-radius: 24px;
    backdrop-filter: blur(8px);
    box-shadow: 0 20px 50px rgba(0, 0, 0, 0.3);
}

/* Info Box */
.info-box {
    background: rgba(255, 255, 255, 0.02);
    border: 1px solid var(--border-color);
    padding: 1.5rem;
    border-radius: 16px;
    transition: var(--transition);
    margin: 1.5rem 0;
}

.info-box:hover {
    background: rgba(255, 255, 255, 0.04);
    border-color: rgba(255, 255, 255, 0.15);
}

.info-box h3 {
    display: flex;
    align-items: center;
    gap: 0.75rem;
    margin-bottom: 1rem;
    font-size: 1.2rem;
    color: var(--text-primary);
}

.info-box h3 i {
    color: var(--accent-blue);
}

/* Callout */
.info-callout {
    margin: 2rem 0;
    padding: 2rem;
    background: rgba(59, 130, 246, 0.05);
    border-radius: 20px;
    border: 1px solid rgba(59, 130, 246, 0.1);
    display: flex;
    gap: 1.5rem;
    align-items: flex-start;
}

.callout-icon {
    font-size: 2rem;
    flex-shrink: 0;
}

.callout-content h4 {
    color: var(--text-primary);
    margin-bottom: 0.5rem;
    font-size: 1.25rem;
}

/* Theory Grid */
.theory-grid {
    display: grid;
    grid-template-columns: repeat(auto-fit, minmax(280px, 1fr));
    gap: 1.5rem;
    margin: 2.5rem 0;
}

.theory-card {
    background: rgba(255, 255, 255, 0.02);
    border: 1px solid var(--border-color);
    padding: 2rem;
    border-radius: 20px;
    transition: var(--transition);
}

.theory-card:hover {
    transform: translateY(-5px);
    background: rgba(255, 255, 255, 0.04);
    border-color: var(--accent-purple);
}

.theory-card i {
    font-size: 2rem;
    color: var(--accent-purple);
    margin-bottom: 1.5rem;
}

/* Tools Section */
.tools-grid {
    display: grid;
    grid-template-columns: repeat(auto-fit, minmax(220px, 1fr));
    gap: 1rem;
    margin-top: 2rem;
}

.tool-item {
    display: flex;
    gap: 1rem;
    align-items: center;
    padding: 1rem;
    background: rgba(255, 255, 255, 0.02);
    border-radius: 12px;
    border: 1px solid var(--border-color);
    transition: var(--transition);
}

.tool-item:hover {
    background: rgba(255, 255, 255, 0.05);
    border-color: var(--accent-blue);
    transform: translateY(-2px);
}

.tool-link {
    margin-left: auto;
    opacity: 0.5;
    transition: var(--transition);
    color: var(--text-primary);
}

.tool-link:hover {
    opacity: 1;
    transform: scale(1.2);
}

/* Summary Box */
.summary-box {
    margin-top: 5rem;
    padding: 3rem;
    background: linear-gradient(135deg, rgba(168, 85, 247, 0.1), rgba(59, 130, 246, 0.1));
    border-radius: 32px;
    border: 1px solid var(--border-color);
    text-align: center;
}

.summary-items {
    display: grid;
    grid-template-columns: repeat(auto-fit, minmax(150px, 1fr));
    gap: 2rem;
    margin-top: 2.5rem;
}

.summary-item {
    display: flex;
    flex-direction: column;
    gap: 0.5rem;
}

.summary-label {
    font-weight: 700;
    color: var(--accent-purple);
    font-size: 0.9rem;
    text-transform: uppercase;
}

/* Animations */
.scroll-indicator {
    position: absolute;
    bottom: 2rem;
    animation: bounce 2s infinite;
    color: var(--text-secondary);
}

@keyframes bounce {

    0%,
    20%,
    50%,
    80%,
    100% {
        transform: translateY(0);
    }

    40% {
        transform: translateY(-10px);
    }

    60% {
        transform: translateY(-5px);
    }
}

/* Responsive */
@media (max-width: 768px) {
    .hero-title {
        font-size: 3rem;
    }

    .hero-subtitle {
        font-size: 1.4rem;
    }

    .glass-card {
        padding: 2rem;
    }

    .nav-links {
        display: none;
    }
}

/* Image Container */
.theory-image-container {
    margin: 2.5rem 0;
    border-radius: 20px;
    overflow: hidden;
    border: 1px solid var(--border-color);
}

.theory-image {
    width: 100%;
    height: auto;
    display: block;
}

.image-caption {
    padding: 1rem;
    background: rgba(0, 0, 0, 0.5);
    font-size: 0.9rem;
    text-align: center;
    color: var(--text-secondary);
}

/* Clickable Image Placeholders */
.image-placeholder {
    margin: 2.5rem 0;
    border-radius: 20px;
    overflow: hidden;
    border: 1px solid var(--border-color);
    background: rgba(0, 0, 0, 0.2);
    transition: var(--transition);
}

.image-placeholder:hover {
    border-color: var(--accent-blue);
    transform: translateY(-2px);
    box-shadow: 0 10px 30px rgba(59, 130, 246, 0.1);
}

.img-link-wrapper {
    text-decoration: none;
    display: block;
    color: inherit;
}

.img-placeholder-inner {
    position: relative;
    padding: 2rem;
    display: flex;
    flex-direction: column;
    align-items: center;
    gap: 1.5rem;
    background: linear-gradient(to bottom, transparent, rgba(59, 130, 246, 0.05));
}

.theory-img {
    max-width: 100%;
    height: auto;
    border-radius: 12px;
    box-shadow: 0 10px 40px rgba(0, 0, 0, 0.5);
}

.img-placeholder-label {
    display: flex;
    flex-direction: column;
    align-items: center;
    text-align: center;
    gap: 0.5rem;
    color: var(--text-secondary);
}

.img-placeholder-label span {
    font-weight: 600;
    color: var(--text-primary);
    font-size: 1.1rem;
}

.img-placeholder-label small {
    font-family: var(--font-mono);
    font-size: 0.75rem;
    opacity: 0.6;
}

.img-link-bar {
    padding: 1rem;
    background: rgba(59, 130, 246, 0.1);
    display: flex;
    align-items: center;
    justify-content: center;
    gap: 0.75rem;
    border-top: 1px solid rgba(59, 130, 246, 0.2);
    transition: var(--transition);
}

.image-placeholder:hover .img-link-bar {
    background: rgba(59, 130, 246, 0.2);
    color: var(--text-primary);
}

.img-link-bar span {
    font-weight: 600;
    font-size: 0.9rem;
}

.img-missing {
    padding: 4rem;
    background: rgba(255, 0, 0, 0.05);
    border: 2px dashed rgba(255, 0, 0, 0.2) !important;
}

.img-missing .theory-img {
    display: none;
}