:root {
    /* Primary Colors */
    --color-primary: #2563eb;
    --color-primary-dark: #1e40af;
    --color-primary-light: #3b82f6;

    /* Secondary Colors */
    --color-secondary: #10b981;
    --color-secondary-dark: #059669;
    --color-secondary-light: #34d399;

    /* Accent Colors */
    --color-accent: #f59e0b;
    --color-accent-dark: #d97706;
    --color-accent-light: #fbbf24;

    /* Neutral Colors */
    --color-dark: #1f2937;
    --color-gray: #6b7280;
    --color-light: #f9fafb;
    --color-white: #ffffff;

    /* Status Colors */
    --color-success: #10b981;
    --color-warning: #f59e0b;
    --color-danger: #ef4444;
    --color-info: #3b82f6;

    /* Text Colors */
    --text-primary: #1f2937;
    --text-secondary: #6b7280;
    --text-light: #9ca3af;

    /* Background Colors */
    --bg-primary: #ffffff;
    --bg-secondary: #f9fafb;
    --bg-dark: #1f2937;

    /* Border Colors */
    --border-light: #e5e7eb;
    --border-medium: #d1d5db;
    --border-dark: #9ca3af;

    /* Shadow */
    --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);

    /* Spacing */
    --container-max-width: 1280px;
    --header-height: 70px;

    /* Border Radius */
    --radius-sm: 0.25rem;
    --radius-md: 0.5rem;
    --radius-lg: 0.75rem;
    --radius-xl: 1rem;

    /* Transitions */
    --transition-fast: 150ms ease;
    --transition-base: 300ms ease;
    --transition-slow: 500ms ease;
}

/* Reset & Base Styles */
* {
    margin: 0;
    padding: 0;
    box-sizing: border-box;
}

body {
    font-family: -apple-system, BlinkMacSystemFont, 'Segoe UI', Roboto, 'Helvetica Neue', Arial, sans-serif;
    color: var(--text-primary);
    background-color: var(--bg-secondary);
    line-height: 1.6;
    -webkit-font-smoothing: antialiased;
    -moz-osx-font-smoothing: grayscale;
}

a {
    color: var(--color-primary);
    text-decoration: none;
    transition: color var(--transition-fast);
}

a:hover {
    color: var(--color-primary-dark);
}

img {
    max-width: 100%;
    height: auto;
}

/* Container */
.container {
    width: 100%;
    max-width: var(--container-max-width);
    margin: 0 auto;
    padding: 0 1rem;
}

@media (min-width: 640px) {
    .container {
        padding: 0 1.5rem;
    }
}

@media (min-width: 1024px) {
    .container {
        padding: 0 2rem;
    }
}

/* Utility Classes */
.text-primary { color: var(--color-primary); }
.text-secondary { color: var(--color-secondary); }
.text-accent { color: var(--color-accent); }
.text-danger { color: var(--color-danger); }
.text-success { color: var(--color-success); }

.bg-primary { background-color: var(--color-primary); }
.bg-secondary { background-color: var(--color-secondary); }
.bg-light { background-color: var(--bg-secondary); }
.bg-white { background-color: var(--bg-primary); }

.btn {
    display: inline-flex;
    align-items: center;
    justify-content: center;
    padding: 0.625rem 1.25rem;
    font-size: 0.875rem;
    font-weight: 500;
    border-radius: var(--radius-md);
    border: none;
    cursor: pointer;
    transition: all var(--transition-fast);
    text-decoration: none;
}

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

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

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

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

.btn-outline {
    background-color: transparent;
    color: var(--color-primary);
    border: 2px solid var(--color-primary);
}

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

.card {
    background-color: var(--bg-primary);
    border-radius: var(--radius-lg);
    box-shadow: var(--shadow-md);
    padding: 1.5rem;
}

/* Loading Spinner */
.spinner {
    border: 3px solid var(--border-light);
    border-top: 3px solid var(--color-primary);
    border-radius: 50%;
    width: 40px;
    height: 40px;
    animation: spin 1s linear infinite;
}

@keyframes spin {
    0% { transform: rotate(0deg); }
    100% { transform: rotate(360deg); }
}

/* Responsive Typography */
h1 { font-size: 2rem; line-height: 1.2; font-weight: 700; }
h2 { font-size: 1.75rem; line-height: 1.3; font-weight: 600; }
h3 { font-size: 1.5rem; line-height: 1.4; font-weight: 600; }
h4 { font-size: 1.25rem; line-height: 1.4; font-weight: 500; }
h5 { font-size: 1.125rem; line-height: 1.5; font-weight: 500; }
h6 { font-size: 1rem; line-height: 1.5; font-weight: 500; }

@media (min-width: 768px) {
    h1 { font-size: 2.5rem; }
    h2 { font-size: 2rem; }
    h3 { font-size: 1.75rem; }
}

@media (min-width: 1024px) {
    h1 { font-size: 3rem; }
    h2 { font-size: 2.25rem; }
}