/* ==========================================================================
   1. RESET & BASE LAYOUT CONFIGURATION
   ========================================================================== */
*, *::before, *::after {
    margin: 0;
    padding: 0;
    box-sizing: border-box;
}

:root {
    /* Color Tokens (Dark Theme - Default) */
    --bg-primary: #09090b;
    --bg-secondary: #18181b;
    --bg-tertiary: #27272a;
    --bg-card: rgba(24, 24, 27, 0.8);
    --bg-glass: rgba(255, 255, 255, 0.03);
    --border-color: rgba(255, 255, 255, 0.08);
    --border-hover: rgba(255, 255, 255, 0.15);
    --text-primary: #fafafa;
    --text-secondary: #a1a1aa;
    --text-muted: #71717a;
    
    /* Accents & Gradients */
    --accent-primary: #6366f1;
    --accent-secondary: #8b5cf6;
    --accent-tertiary: #a78bfa;
    --accent-gradient: linear-gradient(135deg, #6366f1, #8b5cf6, #a78bfa);
    --accent-glow: rgba(99, 102, 241, 0.3);
    
    /* System Feedback Metrics */
    --success: #22c55e;
    --warning: #f59e0b;
    --error: #ef4444;
    
    /* Border Radius Specs */
    --radius-sm: 8px;
    --radius-md: 12px;
    --radius-lg: 16px;
    --radius-xl: 24px;
    --radius-full: 9999px;
    
    /* Elevation Elevation Depths */
    --shadow-sm: 0 1px 2px rgba(0,0,0,0.3);
    --shadow-md: 0 4px 12px rgba(0,0,0,0.4);
    --shadow-lg: 0 8px 32px rgba(0,0,0,0.5);
    --shadow-xl: 0 16px 64px rgba(0,0,0,0.6);
    --shadow-glow: 0 0 40px rgba(99, 102, 241, 0.15);
    
    /* Micro-interaction Rates */
    --transition-fast: 150ms cubic-bezier(0.4, 0, 0.2, 1);
    --transition-base: 250ms cubic-bezier(0.4, 0, 0.2, 1);
    --transition-slow: 400ms cubic-bezier(0.4, 0, 0.2, 1);
    
    /* Typography Typography Stacks */
    --font-sans: 'Inter', -apple-system, BlinkMacSystemFont, sans-serif;
    --font-mono: 'JetBrains Mono', monospace;
}

[data-theme="light"] {
    /* Color Tokens (Light Theme Alternative) */
    --bg-primary: #ffffff;
    --bg-secondary: #f4f4f5;
    --bg-tertiary: #e4e4e7;
    --bg-card: rgba(255, 255, 255, 0.9);
    --bg-glass: rgba(0, 0, 0, 0.02);
    --border-color: rgba(0, 0, 0, 0.08);
    --border-hover: rgba(0, 0, 0, 0.15);
    --text-primary: #09090b;
    --text-secondary: #52525b;
    --text-muted: #a1a1aa;
    
    /* Light Theme Elevation Override */
    --shadow-sm: 0 1px 2px rgba(0,0,0,0.05);
    --shadow-md: 0 4px 12px rgba(0,0,0,0.08);
    --shadow-lg: 0 8px 32px rgba(0,0,0,0.12);
    --shadow-xl: 0 16px 64px rgba(0,0,0,0.16);
}

html {
    scroll-behavior: smooth;
    font-size: 16px;
}

body {
    font-family: var(--font-sans);
    background: var(--bg-primary);
    color: var(--text-primary);
    line-height: 1.6;
    overflow-x: hidden;
    -webkit-font-smoothing: antialiased;
    -moz-osx-font-smoothing: grayscale;
}

/* ==========================================================================
   2. SCROLLBARS & ACCESSIBILITY SPECIFICATIONS
   ========================================================================== */
::-webkit-scrollbar {
    width: 6px;
}
::-webkit-scrollbar-track {
    background: var(--bg-primary);
}
::-webkit-scrollbar-thumb {
    background: var(--bg-tertiary);
    border-radius: 3px;
}
::-webkit-scrollbar-thumb:hover {
    background: var(--text-muted);
}

::selection {
    background: var(--accent-primary);
    color: white;
}

:focus-visible {
    outline: 2px solid var(--accent-primary);
    outline-offset: 2px;
}

.container {
    max-width: 1200px;
    margin: 0 auto;
    padding: 0 24px;
}

.sr-only {
    position: absolute;
    width: 1px;
    height: 1px;
    padding: 0;
    margin: -1px;
    overflow: hidden;
    clip: rect(0, 0, 0, 0);
    border: 0;
}

/* ==========================================================================
   3. UNIVERSAL APPLICATION FORM UX LAYOUTS
   ========================================================================== */
.form-group {
    margin-bottom: 20px;
}

.form-label {
    display: block;
    font-size: 0.8125rem;
    font-weight: 500;
    color: var(--text-secondary);
    margin-bottom: 8px;
}

.form-input {
    width: 100%;
    padding: 12px 16px;
    background: var(--bg-primary);
    border: 1px solid var(--border-color);
    border-radius: var(--radius-md);
    font-size: 0.9375rem;
    color: var(--text-primary);
    font-family: var(--font-sans);
    transition: var(--transition-base);
    outline: none;
}

.form-input:focus {
    border-color: var(--accent-primary);
    box-shadow: 0 0 0 3px rgba(99, 102, 241, 0.1);
}

.form-input::placeholder {
    color: var(--text-muted);
}

.form-select {
    appearance: none;
    background-image: url("data:image/svg+xml,%3Csvg xmlns='http://www.w3.org/2000/svg' width='12' height='12' viewBox='0 0 12 12'%3E%3Cpath fill='%2371717a' d='M6 8L1 3h10z'/%3E%3C/svg%3E");
    background-repeat: no-repeat;
    background-position: right 16px center;
    padding-right: 40px;
}

.form-row {
    display: grid;
    grid-template-columns: 1fr 1fr;
    gap: 16px;
}

/* ==========================================================================
   4. COMPONENT ELEMENT STANDARDS: BUTTON ENGINE
   ========================================================================== */
.btn {
    display: inline-flex;
    align-items: center;
    justify-content: center;
    gap: 8px;
    padding: 10px 20px;
    border-radius: var(--radius-full);
    font-size: 0.875rem;
    font-weight: 600;
    text-decoration: none;
    cursor: pointer;
    border: none;
    transition: var(--transition-base);
    font-family: var(--font-sans);
    white-space: nowrap;
}

.btn-primary {
    background: var(--accent-gradient);
    color: white;
    box-shadow: 0 2px 12px rgba(99, 102, 241, 0.3);
}

.btn-primary:hover {
    transform: translateY(-1px);
    box-shadow: 0 4px 20px rgba(99, 102, 241, 0.4);
}

.btn-secondary {
    background: var(--bg-glass);
    color: var(--text-primary);
    border: 1px solid var(--border-color);
}

.btn-secondary:hover {
    border-color: var(--border-hover);
    background: var(--bg-tertiary);
}

.btn-ghost {
    background: transparent;
    color: var(--text-secondary);
    padding: 8px 16px;
}

.btn-ghost:hover {
    color: var(--text-primary);
    background: var(--bg-glass);
}

.btn-lg {
    padding: 14px 28px;
    font-size: 1rem;
}

.btn-sm {
    padding: 6px 14px;
    font-size: 0.8125rem;
}

.btn-icon {
    width: 40px;
    height: 40px;
    padding: 0;
    border-radius: var(--radius-md);
}

/* ==========================================================================
   5. REDUCED MOTION PREFERENCES
   ========================================================================== */
@media (prefers-reduced-motion: reduce) {
    *, *::before, *::after {
        animation-duration: 0.01ms !important;
        transition-duration: 0.01ms !important;
    }
    html {
        scroll-behavior: auto;
    }
}