/*
 * GA4 Analytics Dashboard - Design System
 * Version: 1.0.0
 *
 * This file contains the core design language for the GA4 Analytics Dashboard.
 * All pages should import this CSS file to maintain design consistency.
 */

/* ===================================
   COLOR PALETTE
   =================================== */

:root {
    /* Primary Colors - Purple Gradient */
    --color-primary-start: #667eea;
    --color-primary-end: #764ba2;
    --color-primary: #667eea;
    --color-primary-dark: #5568d3;
    --color-primary-light: #8b9af7;

    /* Secondary Colors - Indigo */
    --color-secondary: #6366f1;
    --color-secondary-dark: #4f46e5;
    --color-secondary-light: #818cf8;

    /* Accent Colors */
    --color-accent-pink: #f093fb;
    --color-accent-purple: #9333ea;
    --color-accent-blue: #3b82f6;

    /* Success, Warning, Error */
    --color-success: #10b981;
    --color-warning: #f59e0b;
    --color-error: #ef4444;

    /* Neutral Colors - Light Mode */
    --color-gray-50: #f9fafb;
    --color-gray-100: #f3f4f6;
    --color-gray-200: #e5e7eb;
    --color-gray-300: #d1d5db;
    --color-gray-400: #9ca3af;
    --color-gray-500: #6b7280;
    --color-gray-600: #4b5563;
    --color-gray-700: #374151;
    --color-gray-800: #1f2937;
    --color-gray-900: #111827;

    /* Glass Effect */
    --glass-bg: rgba(255, 255, 255, 0.1);
    --glass-border: rgba(255, 255, 255, 0.18);
    --glass-shadow: rgba(31, 38, 135, 0.37);

    /* Spacing Scale */
    --spacing-xs: 0.25rem;   /* 4px */
    --spacing-sm: 0.5rem;    /* 8px */
    --spacing-md: 1rem;      /* 16px */
    --spacing-lg: 1.5rem;    /* 24px */
    --spacing-xl: 2rem;      /* 32px */
    --spacing-2xl: 3rem;     /* 48px */
    --spacing-3xl: 4rem;     /* 64px */

    /* Border Radius */
    --radius-sm: 0.375rem;   /* 6px */
    --radius-md: 0.5rem;     /* 8px */
    --radius-lg: 0.75rem;    /* 12px */
    --radius-xl: 1rem;       /* 16px */
    --radius-2xl: 1.5rem;    /* 24px */
    --radius-full: 9999px;

    /* Shadows */
    --shadow-sm: 0 1px 2px 0 rgba(0, 0, 0, 0.05);
    --shadow-md: 0 4px 6px -1px rgba(0, 0, 0, 0.1);
    --shadow-lg: 0 10px 15px -3px rgba(0, 0, 0, 0.1);
    --shadow-xl: 0 20px 25px -5px rgba(0, 0, 0, 0.1);
    --shadow-2xl: 0 25px 50px -12px rgba(0, 0, 0, 0.25);
    --shadow-glass: 0 8px 32px 0 rgba(31, 38, 135, 0.37);

    /* Transitions */
    --transition-fast: 150ms cubic-bezier(0.4, 0, 0.2, 1);
    --transition-base: 300ms cubic-bezier(0.4, 0, 0.2, 1);
    --transition-slow: 500ms cubic-bezier(0.4, 0, 0.2, 1);

    /* Typography */
    --font-sans: -apple-system, BlinkMacSystemFont, 'Segoe UI', 'Roboto', 'Oxygen', 'Ubuntu', 'Cantarell', sans-serif;
    --font-mono: 'Courier New', Courier, monospace;

    /* Font Sizes */
    --text-xs: 0.75rem;      /* 12px */
    --text-sm: 0.875rem;     /* 14px */
    --text-base: 1rem;       /* 16px */
    --text-lg: 1.125rem;     /* 18px */
    --text-xl: 1.25rem;      /* 20px */
    --text-2xl: 1.5rem;      /* 24px */
    --text-3xl: 1.875rem;    /* 30px */
    --text-4xl: 2.25rem;     /* 36px */
    --text-5xl: 3rem;        /* 48px */

    /* Font Weights */
    --font-normal: 400;
    --font-medium: 500;
    --font-semibold: 600;
    --font-bold: 700;
}

/* Dark Mode Variables */
html.dark {
    --glass-bg: rgba(31, 41, 55, 0.8);
    --glass-border: rgba(75, 85, 99, 0.3);
    --glass-shadow: rgba(0, 0, 0, 0.5);
}

/* ===================================
   GRADIENTS
   =================================== */

.gradient-primary {
    background: linear-gradient(135deg, var(--color-primary-start) 0%, var(--color-primary-end) 100%);
}

.gradient-primary-hover {
    background: linear-gradient(135deg, var(--color-primary-dark) 0%, #6a3f8f 100%);
}

.gradient-secondary {
    background: linear-gradient(135deg, var(--color-secondary) 0%, var(--color-secondary-dark) 100%);
}

.gradient-text {
    background: linear-gradient(135deg, var(--color-primary-start) 0%, var(--color-primary-end) 100%);
    -webkit-background-clip: text;
    -webkit-text-fill-color: transparent;
    background-clip: text;
}

/* ===================================
   GLASS MORPHISM CARDS
   =================================== */

.glass-card {
    position: relative;
    overflow: hidden;
    backdrop-filter: blur(10px);
    -webkit-backdrop-filter: blur(10px);
    background: var(--glass-bg);
    border: 1px solid var(--glass-border);
    box-shadow: var(--shadow-glass);
    border-radius: var(--radius-lg);
    transition: all var(--transition-base);
}

.glass-card::before {
    content: '';
    position: absolute;
    top: 0;
    left: 0;
    right: 0;
    bottom: 0;
    background: linear-gradient(135deg, rgba(255, 255, 255, 0.1) 0%, rgba(255, 255, 255, 0.05) 100%);
    pointer-events: none;
    z-index: 0;
}

.glass-card::after {
    content: '';
    position: absolute;
    top: -50%;
    left: -50%;
    width: 200%;
    height: 200%;
    background: radial-gradient(circle, rgba(255, 255, 255, 0.1) 0%, transparent 70%);
    opacity: 0;
    transition: opacity var(--transition-base);
    pointer-events: none;
}

.glass-card:hover {
    transform: translateY(-4px);
    box-shadow: 0 12px 40px 0 rgba(31, 38, 135, 0.45);
    border-color: rgba(255, 255, 255, 0.28);
}

.glass-card:hover::after {
    opacity: 1;
}

/* Dark mode glass card */
html.dark .glass-card {
    background: var(--glass-bg);
    border-color: var(--glass-border);
}

html.dark .glass-card:hover {
    box-shadow: 0 12px 40px 0 rgba(0, 0, 0, 0.6);
}

/* ===================================
   BUTTONS
   =================================== */

.btn {
    display: inline-flex;
    align-items: center;
    justify-content: center;
    gap: var(--spacing-sm);
    padding: var(--spacing-sm) var(--spacing-lg);
    font-size: var(--text-base);
    font-weight: var(--font-semibold);
    border-radius: var(--radius-lg);
    transition: all var(--transition-fast);
    cursor: pointer;
    border: none;
    outline: none;
    text-decoration: none;
}

.btn:focus {
    outline: 2px solid var(--color-primary);
    outline-offset: 2px;
}

/* Primary Button */
.btn-primary {
    background: linear-gradient(135deg, var(--color-primary-start) 0%, var(--color-primary-end) 100%);
    color: white;
}

.btn-primary:hover {
    background: linear-gradient(135deg, var(--color-primary-dark) 0%, #6a3f8f 100%);
    transform: translateY(-2px);
    box-shadow: var(--shadow-lg);
}

.btn-primary:active {
    transform: translateY(0);
}

/* Secondary Button */
.btn-secondary {
    background: white;
    color: var(--color-primary);
    border: 2px solid var(--color-primary);
}

.btn-secondary:hover {
    background: var(--color-primary);
    color: white;
}

html.dark .btn-secondary {
    background: var(--color-gray-800);
    color: var(--color-primary-light);
    border-color: var(--color-primary-light);
}

html.dark .btn-secondary:hover {
    background: var(--color-primary);
    color: white;
}

/* Outline Button */
.btn-outline {
    background: transparent;
    color: var(--color-gray-700);
    border: 2px solid var(--color-gray-300);
}

.btn-outline:hover {
    background: var(--color-gray-100);
    border-color: var(--color-gray-400);
}

html.dark .btn-outline {
    color: var(--color-gray-200);
    border-color: var(--color-gray-600);
}

html.dark .btn-outline:hover {
    background: var(--color-gray-700);
    border-color: var(--color-gray-500);
}

/* Ghost Button */
.btn-ghost {
    background: transparent;
    color: var(--color-gray-700);
}

.btn-ghost:hover {
    background: var(--color-gray-100);
}

html.dark .btn-ghost {
    color: var(--color-gray-200);
}

html.dark .btn-ghost:hover {
    background: var(--color-gray-700);
}

/* Button Sizes */
.btn-sm {
    padding: var(--spacing-xs) var(--spacing-md);
    font-size: var(--text-sm);
}

.btn-lg {
    padding: var(--spacing-md) var(--spacing-2xl);
    font-size: var(--text-lg);
}

.btn-xl {
    padding: var(--spacing-lg) var(--spacing-3xl);
    font-size: var(--text-xl);
}

/* ===================================
   CARDS
   =================================== */

.card {
    background: white;
    border-radius: var(--radius-xl);
    box-shadow: var(--shadow-lg);
    padding: var(--spacing-xl);
    transition: all var(--transition-base);
}

.card:hover {
    transform: translateY(-4px);
    box-shadow: var(--shadow-2xl);
}

html.dark .card {
    background: var(--color-gray-800);
}

.card-interactive {
    cursor: pointer;
}

.card-bordered {
    border: 2px solid var(--color-gray-200);
}

html.dark .card-bordered {
    border-color: var(--color-gray-700);
}

/* ===================================
   TYPOGRAPHY
   =================================== */

.heading-1 {
    font-size: var(--text-4xl);
    font-weight: var(--font-bold);
    line-height: 1.2;
    color: var(--color-gray-900);
}

.heading-2 {
    font-size: var(--text-3xl);
    font-weight: var(--font-bold);
    line-height: 1.3;
    color: var(--color-gray-900);
}

.heading-3 {
    font-size: var(--text-2xl);
    font-weight: var(--font-semibold);
    line-height: 1.4;
    color: var(--color-gray-900);
}

.heading-4 {
    font-size: var(--text-xl);
    font-weight: var(--font-semibold);
    line-height: 1.5;
    color: var(--color-gray-900);
}

html.dark .heading-1,
html.dark .heading-2,
html.dark .heading-3,
html.dark .heading-4 {
    color: var(--color-gray-100);
}

.text-body {
    font-size: var(--text-base);
    line-height: 1.6;
    color: var(--color-gray-700);
}

html.dark .text-body {
    color: var(--color-gray-300);
}

.text-muted {
    color: var(--color-gray-500);
}

html.dark .text-muted {
    color: var(--color-gray-400);
}

/* ===================================
   LOADING SPINNER
   =================================== */

.spinner {
    display: inline-block;
    width: 20px;
    height: 20px;
    border: 3px solid rgba(255, 255, 255, 0.3);
    border-radius: 50%;
    border-top-color: currentColor;
    animation: spin 1s ease-in-out infinite;
}

.spinner-lg {
    width: 48px;
    height: 48px;
    border-width: 4px;
}

@keyframes spin {
    to { transform: rotate(360deg); }
}

/* ===================================
   ANIMATIONS
   =================================== */

.fade-in {
    animation: fadeIn var(--transition-base) ease-in;
}

@keyframes fadeIn {
    from { opacity: 0; }
    to { opacity: 1; }
}

.slide-up {
    animation: slideUp var(--transition-base) ease-out;
}

@keyframes slideUp {
    from {
        opacity: 0;
        transform: translateY(20px);
    }
    to {
        opacity: 1;
        transform: translateY(0);
    }
}

.scale-in {
    animation: scaleIn var(--transition-base) ease-out;
}

@keyframes scaleIn {
    from {
        opacity: 0;
        transform: scale(0.95);
    }
    to {
        opacity: 1;
        transform: scale(1);
    }
}

/* ===================================
   UTILITIES
   =================================== */

.bg-gradient-primary {
    background: linear-gradient(135deg, var(--color-primary-start) 0%, var(--color-primary-end) 100%);
}

.text-gradient {
    background: linear-gradient(135deg, var(--color-primary-start) 0%, var(--color-primary-end) 100%);
    -webkit-background-clip: text;
    -webkit-text-fill-color: transparent;
    background-clip: text;
}

/* Hover Effects */
.hover-lift {
    transition: transform var(--transition-base);
}

.hover-lift:hover {
    transform: translateY(-4px);
}

.hover-scale {
    transition: transform var(--transition-base);
}

.hover-scale:hover {
    transform: scale(1.05);
}

/* Focus Styles */
.focus-ring:focus {
    outline: 2px solid var(--color-primary);
    outline-offset: 2px;
}

/* Responsive Utilities */
@media (max-width: 768px) {
    :root {
        --text-4xl: 2rem;
        --text-3xl: 1.5rem;
        --text-2xl: 1.25rem;
    }
}