/* ============================================
   CSS Variables (Design Tokens)
   ============================================ */
:root {
    /* Colors */
    --color-primary: #00C853;
    --color-primary-dark: #00A043;
    --color-primary-light: #4CAF50;
    --color-text: #212121;
    --color-text-light: #757575;
    --color-bg: #FFFFFF;
    --color-bg-light: #F5F5F5;
    --color-border: #E0E0E0;
    --color-shadow: rgba(0, 0, 0, 0.1);
    
    /* Spacing */
    --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 */
    
    /* Typography */
    --font-family: -apple-system, BlinkMacSystemFont, 'Segoe UI', Roboto, 'Helvetica Neue', Arial, sans-serif;
    --font-size-xs: 0.75rem;   /* 12px */
    --font-size-sm: 0.875rem;  /* 14px */
    --font-size-base: 1rem;    /* 16px */
    --font-size-lg: 1.125rem;  /* 18px */
    --font-size-xl: 1.25rem;   /* 20px */
    --font-size-2xl: 1.5rem;   /* 24px */
    --font-weight-normal: 400;
    --font-weight-medium: 500;
    --font-weight-semibold: 600;
    --font-weight-bold: 700;
    
    /* Transitions */
    --transition-fast: 150ms ease;
    --transition-base: 200ms ease;
    --transition-slow: 300ms ease;
    
    /* Layout */
    --header-height: 4rem;      /* 64px */
    --header-padding-x: 1.5rem; /* 24px */
    --border-radius: 0.5rem;    /* 8px */
    --border-radius-sm: 0.25rem; /* 4px */
    
    /* Z-index layers */
    --z-header: 1000;
    --z-dropdown: 1001;
}

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

html {
    scroll-behavior: smooth;
}

@media (prefers-reduced-motion: reduce) {
    html {
        scroll-behavior: auto;
    }
    
    *,
    *::before,
    *::after {
        animation-duration: 0.01ms !important;
        animation-iteration-count: 1 !important;
        transition-duration: 0.01ms !important;
    }
}

body {
    font-family: var(--font-family);
    font-size: var(--font-size-base);
    font-weight: var(--font-weight-normal);
    line-height: 1.5;
    color: var(--color-text);
    background-color: var(--color-bg);
    -webkit-font-smoothing: antialiased;
    -moz-osx-font-smoothing: grayscale;
}

/* ============================================
   Typography
   ============================================ */
h1, h2, h3, h4, h5, h6 {
    font-weight: var(--font-weight-bold);
    line-height: 1.2;
    color: var(--color-text);
}

a {
    color: inherit;
    text-decoration: none;
}

button {
    font-family: inherit;
    font-size: inherit;
    cursor: pointer;
    border: none;
    background: none;
}

ul, ol {
    list-style: none;
}

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

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