:root {
    --bg: #020B18;
    --bg-secondary: #04162D;
    --cyan: #39D9FF;
    --blue: #3B82F6;
    --purple: #8B5CF6;
    --text: #F5FAFF;
    --text-secondary: #91A7BD;
    --card-bg: rgba(4, 22, 45, 0.6);
    --border-color: rgba(57, 217, 255, 0.15);
}

* {
    margin: 0;
    padding: 0;
    box-sizing: border-box;
    font-family: 'Segoe UI', Tahoma, Geneva, Verdana, sans-serif;
}

body {
    background-color: var(--bg);
    color: var(--text);
    background: linear-gradient(135deg, #020B18, #04162D, #031326);
    min-height: 100vh;
    display: flex;
    flex-direction: column;
    overflow-x: hidden;
}

main {
    flex: 1;
}

/* ---------------- Header ---------------- */
header {
    position: sticky;
    top: 0;
    left: 0;
    right: 0;
    height: 70px;
    display: flex;
    justify-content: space-between;
    align-items: center;
    padding: 0 5%;
    background: rgba(2, 11, 24, 0.85);
    backdrop-filter: blur(12px);
    border-bottom: 1px solid var(--border-color);
    z-index: 1000;
}

.logo a {
    font-size: 1.5rem;
    font-weight: 700;
    color: var(--text);
    text-decoration: none;
    letter-spacing: 2px;
    transition: all 0.3s;
}

.logo a:hover {
    color: var(--cyan);
    text-shadow: 0 0 10px rgba(57, 217, 255, 0.5);
}

.menu ul {
    list-style: none;
    display: flex;
    gap: 25px;
}

.menu a {
    color: var(--text);
    text-decoration: none;
    font-size: 0.95rem;
    font-weight: 500;
    transition: all 0.3s ease;
    padding: 8px 12px;
    border-radius: 6px;
}

.menu a:hover, .menu a.active {
    color: var(--cyan);
    background: rgba(57, 217, 255, 0.05);
    text-shadow: 0 0 8px rgba(57, 217, 255, 0.4);
}

.hamburger {
    display: none;
    background: none;
    border: none;
    color: var(--text);
    font-size: 1.8rem;
    cursor: pointer;
}

/* ---------------- SPA System ---------------- */
.page {
    display: none;
    opacity: 0;
    transition: opacity 0.5s ease-in-out;
}

.page.active-page {
    display: block;
    opacity: 1;
    animation: fadeIn 0.6s forwards;
}

@keyframes fadeIn {
    from { opacity: 0; transform: translateY(15px); }
    to { opacity: 1; transform: translateY(0); }
}

/* ---------------- Hero / Trang Chủ ---------------- */
#home {
    background-image: linear-gradient(rgba(2, 11, 24, 0.85), rgba(4, 22, 45, 0.95)), url('img/anh_nen.png');
    background-size: cover;
    background-position: center;
    background-repeat: no-repeat;
}

.hero-container {
    display: flex;
    padding: 60px 5%;
    min-height: calc(100vh - 70px);
    align-items: center;
    justify-content: space-between;
    gap: 40px;
}

.hero-left {
    flex: 0 0 45%;
}

.hero-left .badge {
    display: inline-block;
    padding: 6px 14px;
    background: rgba(57, 217, 255, 0.08);
    border: 1px solid rgba(57, 217, 255, 0.4);
    border-radius: 20px;
    font-size: 0.75rem;
    color: var(--cyan);
    margin-bottom: 25px;
    font-weight: 600;
    letter-spacing: 1.5px;
}

.hero-left h1 {
    font-size: 4.5rem;
    margin-bottom: 10px;
    background: linear-gradient(45deg, var(--cyan), var(--blue));
    -webkit-background-clip: text;
    -webkit-text-fill-color: transparent;
    font-weight: 800;
    letter-spacing: 1px;
}

.hero-left h2 {
    font-size: 1.6rem;
    margin-bottom: 25px;
    color: var(--text);
    font-weight: 400;
}

.hero-left p {
    color: var(--text-secondary);
    font-size: 1.1rem;
    line-height: 1.7;
    margin-bottom: 35px;
}

.btn-primary {
    padding: 14px 30px;
    background: linear-gradient(90deg, var(--blue), #2563EB);
    color: #fff;
    border: none;
    border-radius: 30px;
    font-size: 1rem;
    cursor: pointer;
    font-weight: 600;
    transition: all 0.3s ease;
    box-shadow: 0 0 15px rgba(59, 130, 246, 0.4);
}

.btn-primary:hover {
    background: linear-gradient(90deg, var(--cyan), var(--blue));
    box-shadow: 0 0 25px rgba(57, 217, 255, 0.5);
    transform: translateY(-3px);
}

/* ---------------- AI Neural Brain ---------------- */
.hero-right {
    flex: 0 0 55%;
    display: flex;
    justify-content: flex-start;
    align-items: flex-start;
    position: relative;
    padding-top: 20px;
    padding-left: 20px;
    min-height: 650px;
}

.ai-brain {
    position: relative;
    width: 650px;
    height: 600px;
}

.brain-connections {
    position: absolute;
    top: 0;
    left: 0;
    z-index: 1;
    pointer-events: none;
}

.brain-connections path {
    fill: none;
    stroke: var(--cyan);
    stroke-width: 1.2px;
    opacity: 0.3;
}

.node {
    position: absolute;
    width: 90px;
    height: 90px;
    border-radius: 50%;
    background: rgba(4, 22, 45, 0.9);
    border: 2px solid rgba(57, 217, 255, 0.4);
    display: flex;
    flex-direction: column;
    justify-content: center;
    align-items: center;
    font-size: 0.75rem;
    font-weight: 600;
    color: var(--text);
    box-shadow: 0 0 15px rgba(57, 217, 255, 0.1);
    z-index: 2;
    transition: all 0.4s cubic-bezier(0.175, 0.885, 0.32, 1.275);
    cursor: default;
    animation: floatNode 6s ease-in-out infinite;
    backdrop-filter: blur(5px);
    gap: 4px;
    overflow: hidden; /* Ngăn ảnh tràn ra ngoài nếu có lỗi kích thước */
}

.node img {
    width: 32px !important;
    height: 32px !important;
    max-width: 32px;
    border-radius: 6px;
    object-fit: contain;
    background: #fff; /* Đảm bảo logo có nền trắng rõ ràng */
}

.node-label {
    text-align: center;
    line-height: 1.1;
}

.node:hover {
    transform: scale(1.1) !important;
    box-shadow: 0 0 30px rgba(57, 217, 255, 0.6);
    border-color: var(--cyan);
    color: #fff;
    z-index: 3;
    animation-play-state: paused;
}

/* Tọa độ Node - Sắp xếp theo hình bộ não (nhìn ngang) (Đã scale tọa độ) */
.node.deepseek { top: 150px; left: 111px; animation-delay: 2.5s; } /* Thùy trán (trước, trên) */
.node.chatgpt { top: 59px; left: 280px; animation-delay: 0s; } /* Đỉnh đầu */
.node.gemini { top: 150px; left: 449px; animation-delay: 2.1s; } /* Thùy đỉnh (sau, trên) */
.node.grok { top: 319px; left: 501px; animation-delay: 1.8s; } /* Thùy chẩm (sau, nhô ra) */
.node.perplexity { top: 475px; left: 410px; animation-delay: 0.8s; } /* Tiểu não (dưới, sau) */
.node.midjourney { top: 449px; left: 280px; animation-delay: 1.5s; } /* Cuống não (dưới, giữa) */
.node.copilot { top: 319px; left: 150px; animation-delay: 0.5s; } /* Thùy thái dương (trước, dưới) */
.node.claude { top: 241px; left: 293px; animation-delay: 1.2s; } /* Lõi bộ não */

@keyframes floatNode {
    0%, 100% { transform: translateY(0); }
    50% { transform: translateY(-8px); }
}

.featured-news-home {
    margin-top: 40px;
    width: 100%;
    max-width: 400px;
    background: rgba(4, 22, 45, 0.6);
    border: 1px solid rgba(57, 217, 255, 0.3);
    padding: 20px;
    border-radius: 15px;
    backdrop-filter: blur(10px);
    box-shadow: 0 10px 30px rgba(0,0,0,0.4);
    transition: transform 0.3s ease, border-color 0.3s ease;
    z-index: 5;
}

.featured-news-home:hover {
    transform: translateY(-5px);
    border-color: var(--cyan);
}

.featured-news-home .news-tag {
    color: var(--cyan);
    font-size: 0.75rem;
    font-weight: bold;
    letter-spacing: 1px;
    text-transform: uppercase;
    display: block;
    margin-bottom: 8px;
}

.featured-news-home h3 {
    font-size: 1.05rem;
    color: #fff;
    margin-bottom: 8px;
    line-height: 1.4;
}

.featured-news-home p {
    font-size: 0.85rem;
    color: var(--text-secondary);
    margin-bottom: 15px;
    line-height: 1.5;
}

.featured-news-home .read-more {
    color: var(--cyan);
    text-decoration: none;
    font-size: 0.85rem;
    font-weight: 500;
}

.featured-news-home .read-more:hover {
    text-decoration: underline;
}

/* ---------------- Layout Chung Các Trang ---------------- */
.container {
    max-width: 1100px;
    margin: 0 auto;
    padding: 60px 20px;
}

.container h2 {
    font-size: 2.5rem;
    text-align: center;
    margin-bottom: 20px;
    color: var(--text);
    background: linear-gradient(90deg, #fff, var(--cyan));
    -webkit-background-clip: text;
    -webkit-text-fill-color: transparent;
}

.container p {
    text-align: center;
    color: var(--text-secondary);
    margin-bottom: 50px;
}

.text-center { text-align: center; }
.intro { max-width: 750px; margin: 0 auto 50px auto; font-size: 1.1rem; line-height: 1.7; }

/* ---------------- Timeline ---------------- */
.main-img {
    width: 100%;
    border-radius: 15px;
    border: 1px solid var(--border-color);
    box-shadow: 0 10px 30px rgba(0, 0, 0, 0.4), 0 0 20px rgba(57, 217, 255, 0.1);
    margin-bottom: 60px;
    object-fit: cover;
    transition: transform 0.3s;
}

.main-img:hover {
    transform: translateY(-5px);
}

.timeline {
    position: relative;
    max-width: 850px;
    margin: 0 auto;
    padding-top: 20px;
}

.timeline::after {
    content: '';
    position: absolute;
    width: 2px;
    background: linear-gradient(to bottom, var(--cyan), var(--purple));
    top: 0;
    bottom: 0;
    left: 50%;
    margin-left: -1px;
    opacity: 0.3;
}

.timeline-item {
    padding: 10px 40px;
    position: relative;
    width: 50%;
}

.timeline-item::after {
    content: '';
    position: absolute;
    width: 16px;
    height: 16px;
    right: -8px;
    background-color: var(--bg);
    border: 3px solid var(--cyan);
    top: 20px;
    border-radius: 50%;
    z-index: 1;
    box-shadow: 0 0 10px var(--cyan);
}

.left { left: 0; }
.right { left: 50%; }
.right::after { left: -8px; }

.timeline-content {
    padding: 25px;
    background: var(--card-bg);
    border-radius: 12px;
    border: 1px solid var(--border-color);
    position: relative;
    transition: all 0.3s ease;
    backdrop-filter: blur(10px);
}

.timeline-content:hover {
    transform: translateY(-5px);
    box-shadow: 0 8px 25px rgba(0, 0, 0, 0.3);
    border-color: rgba(57, 217, 255, 0.4);
}

.timeline-year {
    font-weight: 700;
    color: var(--cyan);
    font-size: 1.25rem;
    margin-bottom: 8px;
}

.timeline-title {
    font-size: 1.2rem;
    margin-bottom: 12px;
    color: #fff;
}

.timeline-desc {
    font-size: 0.95rem;
    color: var(--text-secondary);
    line-height: 1.6;
    text-align: left;
}

/* ---------------- Grids / Cards ---------------- */
.grid {
    display: grid;
    grid-template-columns: repeat(auto-fit, minmax(320px, 1fr));
    gap: 25px;
    margin-bottom: 40px;
}

.card {
    background: var(--card-bg);
    border: 1px solid var(--border-color);
    border-radius: 15px;
    padding: 30px;
    transition: all 0.3s ease;
    display: flex;
    flex-direction: column;
    backdrop-filter: blur(5px);
}

.card:hover {
    transform: translateY(-8px);
    box-shadow: 0 15px 30px rgba(0,0,0,0.4);
    border-color: rgba(57, 217, 255, 0.3);
}

.card-category {
    color: var(--cyan);
    font-size: 0.8rem;
    text-transform: uppercase;
    letter-spacing: 1.5px;
    margin-bottom: 15px;
    font-weight: 700;
}

.card-title {
    font-size: 1.35rem;
    margin-bottom: 15px;
    color: var(--text);
}

.card-desc {
    font-size: 1rem;
    color: var(--text-secondary);
    line-height: 1.6;
    margin-bottom: 25px;
    flex: 1;
}

.card-meta {
    display: flex;
    justify-content: space-between;
    align-items: center;
    margin-top: auto;
    border-top: 1px solid var(--border-color);
    padding-top: 15px;
}

.card-date {
    font-size: 0.85rem;
    color: var(--text-secondary);
}

.card-btn {
    background: transparent;
    border: 1px solid rgba(57, 217, 255, 0.5);
    color: var(--cyan);
    padding: 6px 18px;
    border-radius: 20px;
    font-size: 0.85rem;
    cursor: pointer;
    transition: all 0.3s ease;
    text-decoration: none;
    font-weight: 500;
}

.card-btn:hover {
    background: rgba(57, 217, 255, 0.1);
    box-shadow: 0 0 10px rgba(57, 217, 255, 0.2);
}

/* ---------------- Custom Components ---------------- */
.notice-box {
    background: rgba(139, 92, 246, 0.05);
    border-left: 4px solid var(--purple);
    padding: 25px 35px;
    border-radius: 0 12px 12px 0;
    margin-top: 50px;
}

.notice-box h3 {
    color: var(--purple);
    margin-bottom: 15px;
    font-size: 1.25rem;
}

.notice-box ul {
    padding-left: 20px;
    color: var(--text-secondary);
    line-height: 1.9;
}

.model-header {
    display: flex;
    align-items: center;
    gap: 15px;
    margin-bottom: 20px;
}

.model-logo {
    width: 50px !important;
    height: 50px !important;
    border-radius: 10px;
    object-fit: contain;
    background: #fff;
    border: 1px solid rgba(57, 217, 255, 0.3);
}

.model-card h3 {
    color: var(--cyan);
    margin-bottom: 3px;
    font-size: 1.25rem;
}

.model-dev {
    font-size: 0.85rem;
    color: var(--text-secondary);
    font-style: italic;
    opacity: 0.8;
}

.model-highlights {
    margin-top: 15px;
    padding-top: 15px;
    border-top: 1px dashed var(--border-color);
    font-size: 0.95rem;
    color: var(--text-secondary);
    line-height: 1.5;
}

/* ---------------- CTA Section ---------------- */
.cta {
    text-align: center;
    padding: 45px 30px;
    background: rgba(59, 130, 246, 0.05);
    border-radius: 20px;
    border: 1px solid rgba(59, 130, 246, 0.2);
    margin-top: 40px;
}

.cta h3 {
    margin-bottom: 25px;
    font-size: 1.6rem;
    color: var(--text);
}

/* ---------------- Footer ---------------- */
footer {
    background: var(--bg-secondary);
    border-top: 1px solid rgba(255,255,255,0.05);
    padding: 50px 5% 30px;
    text-align: center;
    margin-top: auto;
}

.footer-content h3 {
    font-size: 1.5rem;
    color: var(--text);
    margin-bottom: 15px;
    letter-spacing: 2px;
}

.footer-content p {
    color: var(--text-secondary);
    margin-bottom: 25px;
    font-size: 0.95rem;
}

.footer-links {
    display: flex;
    justify-content: center;
    flex-wrap: wrap;
    gap: 25px;
    margin-bottom: 35px;
}

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

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

.copyright {
    font-size: 0.85rem;
    color: rgba(255,255,255,0.3);
    padding-top: 25px;
    border-top: 1px solid rgba(255,255,255,0.05);
}

/* ---------------- Responsive & Mobile ---------------- */
@media (max-width: 1024px) {
    .hero-container {
        flex-direction: column;
        text-align: center;
        padding-top: 40px;
    }
    
    .hero-left, .hero-right {
        flex: 1 1 auto;
        width: 100%;
    }
    
    .hero-left { margin-bottom: 50px; }
    
    .ai-brain {
        transform: scale(0.9);
        transform-origin: center top;
        margin: 0 auto;
    }
    
    .featured-news-home {
        position: relative;
        bottom: auto;
        right: auto;
        margin: 20px auto 0;
        width: 90%;
        max-width: 400px;
    }
}

@media (max-width: 768px) {
    header { padding: 0 20px; }
    
    .hamburger { display: block; }
    
    .menu {
        display: none;
        position: absolute;
        top: 70px;
        left: 0;
        right: 0;
        background: rgba(2, 11, 24, 0.98);
        backdrop-filter: blur(15px);
        padding: 20px 0;
        border-bottom: 1px solid var(--border-color);
        box-shadow: 0 10px 20px rgba(0,0,0,0.5);
    }
    
    .menu.open { display: block; }
    
    .menu ul {
        flex-direction: column;
        gap: 10px;
        align-items: center;
    }
    
    .menu a {
        display: block;
        width: 100%;
        padding: 12px;
    }
    
    .hero-left h1 { font-size: 3.2rem; }
    .hero-left h2 { font-size: 1.3rem; }
    
    .hero-right { height: 380px; }
    .ai-brain { transform: scale(0.7); }
    
    /* Timeline Mobile */
    .timeline::after { left: 31px; }
    .timeline-item { width: 100%; padding-left: 70px; padding-right: 0; }
    .timeline-item::after { left: 23px; }
    .right { left: 0%; }
    
    .container { padding: 40px 15px; }
    .container h2 { font-size: 2rem; }
}

@media (max-width: 480px) {
    .hero-left h1 { font-size: 2.5rem; }
    .hero-right { height: 300px; }
    .ai-brain { transform: scale(0.55); }
    .card { padding: 20px; }
}

/* ---------------- Trang Giải Trí ---------------- */
.ent-header {
    text-align: center;
    margin-bottom: 50px;
}

.mini-game-badge {
    display: inline-block;
    background: rgba(139, 92, 246, 0.2);
    color: var(--purple);
    padding: 5px 15px;
    border-radius: 20px;
    font-size: 0.85rem;
    font-weight: bold;
    margin-top: 15px;
    border: 1px solid rgba(139, 92, 246, 0.4);
}

.game-container {
    max-width: 900px;
    margin: 0 auto;
    background: rgba(4, 22, 45, 0.8);
    border: 1px solid rgba(57,217,255,0.25);
    border-radius: 24px;
    padding: 40px;
    backdrop-filter: blur(10px);
    box-shadow: 0 10px 40px rgba(0,0,0,0.3);
    text-align: center;
}

.game-title {
    font-size: 48px;
    background: linear-gradient(90deg, #fff, var(--cyan));
    -webkit-background-clip: text;
    -webkit-text-fill-color: transparent;
    margin-bottom: 5px;
}

.game-subtitle {
    color: var(--text-secondary);
    font-size: 1.1rem;
    margin-bottom: 30px;
}

.game-progress-wrapper {
    margin-bottom: 40px;
}

.progress-text {
    font-weight: 600;
    margin-bottom: 10px;
    color: var(--cyan);
}

.progress-bar-bg {
    width: 100%;
    height: 8px;
    background: rgba(255,255,255,0.1);
    border-radius: 4px;
    overflow: hidden;
}

.progress-bar-fill {
    height: 100%;
    width: 0%;
    background: var(--cyan);
    transition: width 0.5s ease;
}

.game-step {
    display: none;
    animation: fadeInStep 0.5s forwards;
}

.game-step.active-step {
    display: block;
}

@keyframes fadeInStep {
    from { opacity: 0; transform: translateY(10px); }
    to { opacity: 1; transform: translateY(0); }
}

.prediction-card {
    display: inline-block;
    border: 1px solid rgba(57, 217, 255, 0.5);
    border-radius: 12px;
    padding: 20px 40px;
    background: rgba(4, 22, 45, 0.5);
    box-shadow: 0 0 20px rgba(57, 217, 255, 0.1);
    margin-bottom: 25px;
}

.prediction-header {
    font-size: 0.85rem;
    color: var(--text-secondary);
    margin-bottom: 15px;
    letter-spacing: 2px;
}

.prediction-content {
    font-size: 2rem;
    letter-spacing: 10px;
    color: var(--cyan);
    margin-bottom: 15px;
}

.prediction-footer {
    font-size: 0.8rem;
    color: var(--purple);
}

.ai-speech {
    font-size: 1.1rem;
    color: var(--text-secondary);
    margin-bottom: 30px;
    font-style: italic;
}

.highlight-text {
    color: var(--text);
    font-weight: 500;
}

.game-btn {
    font-size: 1.1rem;
    padding: 15px 40px;
}

.step-title {
    font-size: 1.8rem;
    color: var(--cyan);
    margin-bottom: 15px;
}

.step-inst {
    font-size: 1.2rem;
    margin-bottom: 20px;
}

.step-rules {
    text-align: left;
    display: inline-block;
    margin: 0 auto 20px;
    color: var(--text-secondary);
    padding-left: 20px;
}

.step-example {
    background: rgba(255,255,255,0.05);
    padding: 15px;
    border-radius: 8px;
    margin-bottom: 30px;
    display: inline-block;
    font-family: monospace;
    font-size: 1.2rem;
}

.animation-box {
    display: flex;
    flex-direction: column;
    align-items: center;
    margin-bottom: 30px;
    font-family: monospace;
    font-size: 2rem;
    font-weight: bold;
    color: #fff;
}

.anim-arrow {
    color: var(--cyan);
    margin: 10px 0;
}

.formula-box {
    font-size: 1.8rem;
    font-weight: bold;
    color: #fff;
    margin: 30px 0;
    padding: 20px;
    border: 2px dashed rgba(57, 217, 255, 0.3);
    border-radius: 12px;
}

.note-box {
    font-size: 0.9rem;
    color: var(--text-secondary);
    margin-bottom: 30px;
}

.math-box {
    display: inline-block;
    text-align: right;
    font-family: monospace;
    font-size: 1.5rem;
    margin-bottom: 30px;
    background: rgba(0,0,0,0.2);
    padding: 20px 40px;
    border-radius: 10px;
}

.math-row {
    padding: 5px 0;
}

.border-bottom {
    border-bottom: 2px solid var(--text-secondary);
    margin-bottom: 10px;
    padding-bottom: 10px;
}

.text-cyan {
    color: var(--cyan);
    font-weight: bold;
}

.dots {
    animation: blink 1.5s infinite;
}

@keyframes blink {
    0% { opacity: 0.2; }
    50% { opacity: 1; }
    100% { opacity: 0.2; }
}

.reveal-number {
    font-size: 100px;
    font-weight: 800;
    color: var(--cyan);
    text-shadow: 0 0 40px rgba(57, 217, 255, 0.6);
    margin: 20px 0 40px;
    animation: scaleIn 0.8s cubic-bezier(0.175, 0.885, 0.32, 1.275) forwards;
}

@keyframes scaleIn {
    from { transform: scale(0.5); opacity: 0; }
    to { transform: scale(1); opacity: 1; }
}

.btn-group {
    display: flex;
    gap: 20px;
    justify-content: center;
    margin-bottom: 30px;
}

.btn-outline {
    padding: 14px 30px;
    background: transparent;
    color: var(--text);
    border: 1px solid var(--border-color);
    border-radius: 30px;
    font-size: 1rem;
    cursor: pointer;
    font-weight: 600;
    transition: all 0.3s ease;
}

.btn-outline:hover {
    background: rgba(255,255,255,0.05);
    border-color: #fff;
}

.math-secret-box {
    text-align: left;
    background: rgba(0,0,0,0.3);
    padding: 25px;
    border-radius: 12px;
    border-left: 4px solid var(--purple);
    margin-top: 20px;
    animation: fadeInStep 0.4s forwards;
}

.math-secret-box h4 {
    color: var(--purple);
    margin-bottom: 15px;
}

.math-explanation {
    margin-top: 15px;
    color: var(--text-secondary);
    line-height: 1.8;
}

/* Quiz Styles */
.quiz-container {
    background: rgba(4, 22, 45, 0.5);
    border: 1px solid var(--border-color);
    border-radius: 15px;
    padding: 30px;
}

.quiz-options {
    display: flex;
    flex-direction: column;
    gap: 10px;
    margin-top: 20px;
}

.quiz-options button {
    background: rgba(255,255,255,0.05);
    border: 1px solid var(--border-color);
    padding: 15px 20px;
    border-radius: 8px;
    color: var(--text);
    text-align: left;
    font-size: 1rem;
    cursor: pointer;
    transition: all 0.2s;
}

.quiz-options button:hover {
    background: rgba(57, 217, 255, 0.1);
    border-color: var(--cyan);
}

.quiz-options button.correct {
    background: rgba(16, 185, 129, 0.2);
    border-color: #10B981;
    color: #10B981;
}

.quiz-options button.incorrect {
    background: rgba(239, 68, 68, 0.2);
    border-color: #EF4444;
    color: #EF4444;
}

.quiz-result-box {
    text-align: center;
    padding: 30px;
    background: rgba(0,0,0,0.2);
    border-radius: 12px;
    margin-top: 20px;
}

.quiz-result-box h3 {
    font-size: 1.5rem;
    color: var(--cyan);
    margin-bottom: 10px;
}

/* Mobile responsive for Game */
@media (max-width: 768px) {
    .game-container { padding: 25px 15px; }
    .game-title { font-size: 32px; }
    .step-title { font-size: 1.5rem; }
    .reveal-number { font-size: 64px; }
    .btn-group { flex-direction: column; }
    .game-btn { width: 100%; }
}