@import url('https://fonts.googleapis.com/css2?family=Outfit:wght@300;400;600;800&display=swap');

:root {
    --bg-color: #050510;
    --card-bg: rgba(30, 30, 45, 0.6);
    --primary: #6366f1;
    --secondary: #a855f7;
    --accent: #22d3ee;
    --text-main: #f8fafc;
    --text-muted: #94a3b8;
    --glass-border: rgba(255, 255, 255, 0.1);
    --color-group-1: #4ade80;
    --color-group-2: #60a5fa;
    --color-group-3: #facc15;
}

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

body {
    font-family: 'Outfit', sans-serif;
    background-color: var(--bg-color);
    color: var(--text-main);
    overflow-x: hidden;
    min-height: 100vh;
    background-image:
        radial-gradient(circle at 15% 50%, rgba(99, 102, 241, 0.15) 0%, transparent 25%),
        radial-gradient(circle at 85% 30%, rgba(168, 85, 247, 0.15) 0%, transparent 25%);
}

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

header {
    text-align: center;
    margin-bottom: 4rem;
    animation: fadeInDown 0.8s ease-out;
}

h1 {
    font-size: 3rem;
    font-weight: 800;
    background: linear-gradient(135deg, var(--text-main) 0%, var(--primary) 100%);
    background-clip: text;
    -webkit-background-clip: text;
    -webkit-text-fill-color: transparent;
    margin-bottom: 1rem;
}

.subtitle {
    font-size: 1.25rem;
    color: var(--text-muted);
}

.concepts-grid {
    column-count: 3;
    column-gap: 1.5rem;
}

.concept-card {
    background: var(--card-bg);
    border: 1px solid var(--glass-border);
    border-radius: 16px;
    padding: 1.5rem;
    text-decoration: none;
    color: var(--text-main);
    transition: all 0.3s cubic-bezier(0.4, 0, 0.2, 1);
    backdrop-filter: blur(10px);
    display: flex;
    flex-direction: column;
    justify-content: center;
    height: 180px;
    break-inside: avoid;
    margin-bottom: 1.5rem;
}

.concept-card:hover {
    transform: translateY(-5px);
    border-color: var(--primary);
    box-shadow: 0 10px 40px -10px rgba(99, 102, 241, 0.3);
}

.card-number {
    font-size: 0.9rem;
    color: var(--primary);
    font-weight: 600;
    margin-bottom: 0.5rem;
    opacity: 0.8;
}

.card-title {
    font-size: 1.5rem;
    font-weight: 600;
    line-height: 1.2;
}

.nav-back {
    display: inline-flex;
    align-items: center;
    color: var(--text-muted);
    text-decoration: none;
    margin-bottom: 2rem;
    font-weight: 600;
    transition: color 0.2s;
}

.nav-back:hover {
    color: var(--text-main);
}

.nav-back svg {
    margin-right: 0.5rem;
}

/* Concept Detail Page Layout */
.concept-layout {
    display: grid;
    grid-template-columns: 1fr 1fr;
    gap: 4rem;
    align-items: center;
    min-height: 60vh;
}

.concept-info h1 {
    font-size: 3.5rem;
}

.concept-desc {
    font-size: 1.1rem;
    line-height: 1.7;
    color: var(--text-muted);
    margin-top: 2rem;
}

.visualization-container {
    background: #0f172a;
    border-radius: 20px;
    border: 1px solid var(--glass-border);
    height: 400px;
    width: 100%;
    position: relative;
    overflow: hidden;
    box-shadow: 0 20px 50px -20px #000;
    display: flex;
    align-items: center;
    justify-content: center;
}

@media (max-width: 768px) {
    .concept-layout {
        grid-template-columns: 1fr;
    }

    .concepts-grid {
        column-count: 1;
    }
}

.group-1 .card-number {
    color: var(--color-group-1);
}

.group-1:hover {
    border-color: var(--color-group-1);
}

.group-1:hover {
    box-shadow: 0 10px 40px -10px rgba(74, 222, 128, 0.3);
}

.group-2 .card-number {
    color: var(--color-group-2);
}

.group-2:hover {
    border-color: var(--color-group-2);
}

.group-2:hover {
    box-shadow: 0 10px 40px -10px rgba(96, 165, 250, 0.3);
}

.group-3 .card-number {
    color: var(--color-group-3);
}

.group-3:hover {
    border-color: var(--color-group-3);
}

.group-3:hover {
    box-shadow: 0 10px 40px -10px rgba(250, 204, 21, 0.3);
}

@keyframes fadeInDown {
    from {
        opacity: 0;
        transform: translateY(-20px);
    }

    to {
        opacity: 1;
        transform: translateY(0);
    }
}
/* Navigation Controls */
.concept-navigation {
    display: flex;
    justify-content: space-between;
    margin-top: 4rem;
    padding-top: 2rem;
    border-top: 1px solid var(--glass-border);
}

.nav-btn {
    display: inline-flex;
    align-items: center;
    padding: 0.75rem 1.5rem;
    background: rgba(255, 255, 255, 0.05);
    border: 1px solid var(--glass-border);
    border-radius: 8px;
    color: var(--text-main);
    text-decoration: none;
    transition: all 0.3s ease;
    font-weight: 500;
}

.nav-btn:hover {
    background: rgba(255, 255, 255, 0.1);
    transform: translateY(-2px);
    border-color: var(--primary);
}

.nav-btn.disabled {
    opacity: 0.5;
    pointer-events: none;
    visibility: hidden;
}

.nav-btn svg {
    width: 20px;
    height: 20px;
}

.nav-prev svg {
    margin-right: 0.5rem;
}

.nav-next svg {
    margin-left: 0.5rem;
}

/* Language Selector */
.lang-selector {
    position: fixed;
    top: 20px;
    right: 20px;
    display: flex;
    gap: 10px;
    z-index: 1000;
    backdrop-filter: blur(10px);
    background: rgba(30, 30, 45, 0.8);
    padding: 10px;
    border-radius: 20px;
    border: 1px solid var(--glass-border);
}

.lang-selector button {
    background: transparent;
    border: none;
    color: var(--text-muted);
    font-weight: 600;
    cursor: pointer;
    font-family: inherit;
    padding: 5px 10px;
    border-radius: 10px;
    transition: all 0.2s;
}

.lang-selector button:hover {
    color: var(--text-main);
}

.lang-selector button.active {
    background: var(--primary);
    color: white;
}