/* CSS Custom Properties - Easy to customize */
:root {
    /* Colors */
    --color-primary: #000000;
    --color-secondary: #ffffff;
    --color-accent: #cccccc;
    --color-text: #333333;
    --color-text-light: #666666;
    --color-background: #ffffff;
    --color-background-alt: #f5f5f5;
    --color-border: #e0e0e0;
    
    /* Typography */
    --font-primary: -apple-system, BlinkMacSystemFont, 'Segoe UI', Roboto, Oxygen, Ubuntu, Cantarell, sans-serif;
    --font-heading: var(--font-primary);
    
    --font-size-base: 16px;
    --font-size-small: 14px;
    --font-size-large: 18px;
    --font-size-h1: 3rem;
    --font-size-h2: 2.5rem;
    --font-size-h3: 2rem;
    --font-size-h4: 1.5rem;
    
    --line-height-base: 1.6;
    --line-height-heading: 1.2;
    
    /* Spacing */
    --spacing-xs: 0.5rem;
    --spacing-sm: 1rem;
    --spacing-md: 2rem;
    --spacing-lg: 3rem;
    --spacing-xl: 4rem;
    
    /* Layout */
    --container-max-width: 1200px;
    --container-padding: 1rem;
    
    /* Transitions */
    --transition-base: 0.3s ease;
    --transition-fast: 0.15s ease;
    
    /* Border Radius */
    --radius-sm: 4px;
    --radius-md: 8px;
    --radius-lg: 12px;
}

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

html {
    font-size: var(--font-size-base);
    scroll-behavior: smooth;
}

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

/* Typography */
h1, h2, h3, h4, h5, h6 {
    font-family: var(--font-heading);
    font-weight: 700;
    line-height: var(--line-height-heading);
    margin-bottom: var(--spacing-sm);
    color: var(--color-primary);
}

h1 {
    font-size: var(--font-size-h1);
}

h2 {
    font-size: var(--font-size-h2);
}

h3 {
    font-size: var(--font-size-h3);
}

h4 {
    font-size: var(--font-size-h4);
}

p {
    margin-bottom: var(--spacing-sm);
}

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

a:hover {
    color: var(--color-text-light);
}

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

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

ul, ol {
    list-style: none;
}

/* Utility Classes */
.visually-hidden {
    position: absolute;
    width: 1px;
    height: 1px;
    padding: 0;
    margin: -1px;
    overflow: hidden;
    clip: rect(0, 0, 0, 0);
    white-space: nowrap;
    border-width: 0;
}

.text-center {
    text-align: center;
}

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