:root {
    /* Color Palette - Vibrant Dark Theme */
    --background: #0f172a;
    --surface: #1e293b;
    --surface-glass: rgba(30, 41, 59, 0.6);
    --surface-border: rgba(255, 255, 255, 0.08);
    
    --primary: #8b5cf6;
    --primary-hover: #7c3aed;
    --secondary: #ec4899;
    --secondary-hover: #db2777;
    --accent: #06b6d4;
    
    --text: #f8fafc;
    --text-muted: #94a3b8;
    
    --success: #10b981;
    --error: #ef4444;

    /* Semantic Game Colors */
    --vowel-bg: #ec4899;         /* Pink */
    --consonant-bg: #3b82f6;     /* Blue */
    --vowel-shadow: rgba(236, 72, 153, 0.4);
    --consonant-shadow: rgba(59, 130, 246, 0.4);

    /* Typographic Details */
    --font-ui: 'Inter', system-ui, -apple-system, sans-serif;
    --font-kr: 'Noto Sans KR', sans-serif;
    
    /* Layout */
    --radius-sm: 8px;
    --radius-md: 12px;
    --radius-lg: 24px;
    --radius-full: 9999px;
}

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

body {
    font-family: var(--font-ui);
    background-color: var(--background);
    color: var(--text);
    line-height: 1.5;
    -webkit-font-smoothing: antialiased;
    -moz-osx-font-smoothing: grayscale;
}

/* Typography styles */
.kr-text {
    font-family: var(--font-kr);
    font-weight: 700;
}

/* Reusable Buttons */
.btn {
    display: inline-flex;
    align-items: center;
    justify-content: center;
    appearance: none;
    background: var(--surface);
    border: 1px solid var(--surface-border);
    color: var(--text);
    padding: 0.75rem 1.5rem;
    font-size: 1rem;
    font-weight: 600;
    border-radius: var(--radius-md);
    cursor: pointer;
    transition: all 0.2s cubic-bezier(0.175, 0.885, 0.32, 1.275);
    font-family: var(--font-ui);
    user-select: none;
    -webkit-tap-highlight-color: transparent;
}

.btn:hover {
    transform: scale(1.05);
    box-shadow: 0 4px 12px rgba(0,0,0,0.2);
}

.btn:active {
    transform: scale(0.95);
}

.btn-primary {
    background: var(--primary);
    border: none;
    box-shadow: 0 4px 15px rgba(139, 92, 246, 0.3);
}

.btn-primary:hover {
    background: var(--primary-hover);
    box-shadow: 0 6px 20px rgba(139, 92, 246, 0.5);
}

/* Glassmorphism panel utility */
.glass-panel {
    background: var(--surface-glass);
    backdrop-filter: blur(16px);
    -webkit-backdrop-filter: blur(16px);
    border: 1px solid var(--surface-border);
    border-radius: var(--radius-lg);
    box-shadow: 0 8px 32px rgba(0, 0, 0, 0.2);
}

/* Useful Animations */
@keyframes popIn {
    0% { transform: scale(0.8); opacity: 0; }
    70% { transform: scale(1.05); }
    100% { transform: scale(1); opacity: 1; }
}

@keyframes shake {
    0%, 100% { transform: translateX(0); }
    20% { transform: translateX(-6px); }
    40% { transform: translateX(6px); }
    60% { transform: translateX(-6px); }
    80% { transform: translateX(6px); }
}

@keyframes pulse {
    0% { transform: scale(1); box-shadow: 0 0 0 0 rgba(16, 185, 129, 0.7); }
    70% { transform: scale(1.05); box-shadow: 0 0 0 10px rgba(16, 185, 129, 0); }
    100% { transform: scale(1); box-shadow: 0 0 0 0 rgba(16, 185, 129, 0); }
}

.animate-pop-in {
    animation: popIn 0.4s cubic-bezier(0.175, 0.885, 0.32, 1.275) forwards;
}

.animate-shake {
    animation: shake 0.4s ease-in-out;
}

.animate-success-pulse {
    animation: pulse 1s infinite;
}