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

:root {
    --text-primary: #ffffff;
    --text-secondary: #94a3b8;
    --card-bg: rgba(15, 23, 42, 0.7);
    --code-bg: #0a0e1a;
    --code-text: #10b981;
    --error-bg: rgba(239, 68, 68, 0.1);
    --warning-bg: rgba(251, 191, 36, 0.1);
}

body {
    font-family: 'Inter', sans-serif;
    color: var(--text-primary);
    line-height: 1.6;
    overflow-x: hidden;
    min-height: 100vh;
}

/* ANIMATED RAINBOW DARK BACKGROUND */
.bg-animation {
    position: fixed;
    top: 0;
    left: 0;
    width: 100%;
    height: 100%;
    z-index: -1;
    background: linear-gradient(135deg, 
        #000000 0%, 
        #8b5cf6 16%, 
        #3b82f6 33%, 
        #10b981 50%, 
        #fbbf24 66%, 
        #ef4444 83%, 
        #000000 100%);
    background-size: 400% 400%;
    animation: rainbowShift 20s ease infinite;
}

.bg-animation::before {
    content: '';
    position: absolute;
    width: 100%;
    height: 100%;
    background: 
        radial-gradient(circle at 20% 50%, rgba(139, 92, 246, 0.15) 0%, transparent 50%),
        radial-gradient(circle at 80% 80%, rgba(59, 130, 246, 0.15) 0%, transparent 50%),
        radial-gradient(circle at 40% 20%, rgba(16, 185, 129, 0.15) 0%, transparent 50%);
}

@keyframes rainbowShift {
    0% { background-position: 0% 50%; }
    25% { background-position: 50% 100%; }
    50% { background-position: 100% 50%; }
    75% { background-position: 50% 0%; }
    100% { background-position: 0% 50%; }
}

.container {
    max-width: 1100px;
    margin: 0 auto;
    padding: 40px 20px;
    position: relative;
    z-index: 1;
}

/* HEADER / LOGO */
.header {
    text-align: center;
    padding: 80px 0 60px;
}

.logo {
    font-family: 'Orbitron', sans-serif;
    font-size: 72px;
    font-weight: 900;
    background: linear-gradient(135deg, #8b5cf6, #3b82f6, #10b981, #fbbf24, #ef4444);
    background-size: 200% 200%;
    -webkit-background-clip: text;
    -webkit-text-fill-color: transparent;
    background-clip: text;
    margin-bottom: 15px;
    letter-spacing: 3px;
    animation: logoGlow 3s ease-in-out infinite, rainbowText 8s ease infinite;
    text-shadow: 0 0 30px rgba(139, 92, 246, 0.3);
}

@keyframes logoGlow {
    0%, 100% { filter: brightness(1); }
    50% { filter: brightness(1.3); }
}

@keyframes rainbowText {
    0% { background-position: 0% 50%; }
    50% { background-position: 100% 50%; }
    100% { background-position: 0% 50%; }
}

.tagline {
    font-family: 'Orbitron', sans-serif;
    font-size: 18px;
    color: var(--text-secondary);
    text-transform: uppercase;
    letter-spacing: 4px;
}

/* SOCIAL LINKS - PENTAGON LAYOUT */
.social-section {
    text-align: center;
    margin: 60px 0;
}

.social-section h2 {
    font-family: 'Orbitron', sans-serif;
    font-size: 28px;
    color: var(--text-primary);
    margin-bottom: 40px;
}

.social-pentagon {
    display: flex;
    flex-wrap: wrap;
    justify-content: center;
    gap: 30px;
    max-width: 500px;
    margin: 0 auto;
}

.social-btn {
    width: 80px;
    height: 80px;
    border-radius: 50%;
    display: flex;
    align-items: center;
    justify-content: center;
    text-decoration: none;
    font-size: 32px;
    color: white;
    transition: all 0.3s ease;
    border: 3px solid rgba(255, 255, 255, 0.2);
    position: relative;
    overflow: hidden;
}

.social-btn::before {
    content: '';
    position: absolute;
    top: 0;
    left: 0;
    width: 100%;
    height: 100%;
    background: rgba(255, 255, 255, 0.1);
    opacity: 0;
    transition: opacity 0.3s ease;
}

.social-btn:hover {
    transform: scale(1.15) translateY(-5px);
    box-shadow: 0 15px 40px rgba(0, 0, 0, 0.4);
    border-color: rgba(255, 255, 255, 0.5);
}

.social-btn:hover::before {
    opacity: 1;
}

.social-btn.zalo {
    background: linear-gradient(135deg, #0068ff, #0099ff);
}

.social-btn.telegram {
    background: linear-gradient(135deg, #0088cc, #00aaff);
}

.social-btn.youtube {
    background: linear-gradient(135deg, #ff0000, #cc0000);
}

.social-btn.tiktok {
    background: linear-gradient(135deg, #000000, #333333);
    border-color: rgba(255, 255, 255, 0.4);
}

.social-btn.group-zalo {
    background: linear-gradient(135deg, #0068ff, #4da6ff);
}

.social-label {
    display: block;
    margin-top: 10px;
    font-size: 12px;
    color: var(--text-secondary);
    font-weight: 600;
}

/* CARDS */
.card {
    background: var(--card-bg);
    backdrop-filter: blur(20px);
    -webkit-backdrop-filter: blur(20px);
    border-radius: 20px;
    padding: 40px;
    margin-bottom: 30px;
    border: 1px solid rgba(255, 255, 255, 0.1);
    transition: all 0.3s ease;
}

.card:hover {
    border-color: rgba(139, 92, 246, 0.5);
    box-shadow: 0 20px 60px rgba(139, 92, 246, 0.2);
}

.card-title {
    font-family: 'Orbitron', sans-serif;
    font-size: 28px;
    color: var(--text-primary);
    margin-bottom: 30px;
    display: flex;
    align-items: center;
    gap: 15px;
}

/* STEPS */
.step {
    margin-bottom: 40px;
}

.step-title {
    font-family: 'Orbitron', sans-serif;
    font-size: 20px;
    color: var(--text-primary);
    margin-bottom: 15px;
    display: flex;
    align-items: center;
    gap: 15px;
}

.step-number {
    background: linear-gradient(135deg, #8b5cf6, #3b82f6);
    color: white;
    width: 40px;
    height: 40px;
    border-radius: 50%;
    display: flex;
    align-items: center;
    justify-content: center;
    font-weight: 900;
    font-size: 18px;
    flex-shrink: 0;
}

.step-text {
    color: var(--text-secondary);
    font-size: 16px;
    line-height: 1.8;
    margin-bottom: 15px;
}

.step-text a {
    color: #3b82f6;
    font-weight: 600;
    text-decoration: none;
}

.step-text a:hover {
    text-decoration: underline;
}

/* CODE BLOCKS */
.code-block {
    background: var(--code-bg);
    border-radius: 12px;
    padding: 20px;
    margin: 15px 0;
    position: relative;
    border: 1px solid rgba(16, 185, 129, 0.3);
    overflow-x: auto;
}

.code-block pre {
    color: var(--code-text);
    font-family: 'Courier New', monospace;
    font-size: 14px;
    white-space: pre-wrap;
    word-wrap: break-word;
    margin: 0;
}

.copy-btn {
    position: absolute;
    top: 10px;
    right: 10px;
    background: var(--code-text);
    color: #000;
    border: none;
    padding: 8px 18px;
    border-radius: 8px;
    cursor: pointer;
    font-weight: 700;
    font-size: 13px;
    transition: all 0.3s ease;
    font-family: 'Orbitron', sans-serif;
}

.copy-btn:hover {
    background: #34d399;
    transform: scale(1.05);
}

/* ERROR BOXES */
.error-section {
    margin-top: 40px;
}

.error-section h3 {
    font-family: 'Orbitron', sans-serif;
    font-size: 22px;
    color: #ef4444;
    margin-bottom: 25px;
    display: flex;
    align-items: center;
    gap: 10px;
}

.error-box {
    background: var(--error-bg);
    border-left: 5px solid #ef4444;
    padding: 20px;
    border-radius: 12px;
    margin-bottom: 20px;
    border: 1px solid rgba(239, 68, 68, 0.3);
}

.error-title {
    color: #ef4444;
    font-weight: 700;
    font-size: 16px;
    margin-bottom: 10px;
    font-family: 'Orbitron', sans-serif;
}

.error-text {
    color: var(--text-secondary);
    margin-bottom: 15px;
    line-height: 1.8;
}

/* FOOTER */
.footer {
    text-align: center;
    margin-top: 60px;
    padding: 40px 0;
    border-top: 1px solid rgba(255, 255, 255, 0.1);
    color: var(--text-secondary);
    font-size: 14px;
}

/* RESPONSIVE */
@media (max-width: 768px) {
    .logo {
        font-size: 48px;
    }
    
    .tagline {
        font-size: 14px;
        letter-spacing: 2px;
    }
    
    .header {
        padding: 60px 0 40px;
    }
    
    .card {
        padding: 25px;
    }
    
    .card-title {
        font-size: 22px;
    }
    
    .social-pentagon {
        gap: 20px;
    }
    
    .social-btn {
        width: 65px;
        height: 65px;
        font-size: 26px;
    }
    
    .step-title {
        font-size: 18px;
    }
    
    .code-block {
        padding: 15px;
    }
    
    .code-block pre {
        font-size: 12px;
    }
    
    .copy-btn {
        padding: 6px 12px;
        font-size: 11px;
    }
}

@media (max-width: 480px) {
    .logo {
        font-size: 36px;
    }
    
    .container {
        padding: 20px 15px;
    }
    
    .social-btn {
        width: 55px;
        height: 55px;
        font-size: 22px;
    }
}