/* ============================================
   Base Styles & Reset
   ============================================ */

* {
    margin: 0;
    padding: 0;
    box-sizing: border-box;
}

:root {
    /* Typography */
    --font-heading: 'Inter', -apple-system, BlinkMacSystemFont, 'Segoe UI', sans-serif;
    --font-body: 'Inter', -apple-system, BlinkMacSystemFont, 'Segoe UI', sans-serif;
    --font-serif: 'Playfair Display', Georgia, serif;
    
    /* Spacing */
    --spacing-xs: 0.25rem;
    --spacing-sm: 0.5rem;
    --spacing-md: 1rem;
    --spacing-lg: 1.5rem;
    --spacing-xl: 2rem;
    --spacing-2xl: 3rem;
    
    /* Transitions */
    --transition-fast: 0.15s cubic-bezier(0.4, 0, 0.2, 1);
    --transition-base: 0.3s cubic-bezier(0.4, 0, 0.2, 1);
    --transition-slow: 0.5s cubic-bezier(0.4, 0, 0.2, 1);
    
    /* Border Radius */
    --radius-sm: 0.375rem;
    --radius-md: 0.5rem;
    --radius-lg: 0.75rem;
    --radius-xl: 1rem;
    --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), 0 2px 4px -1px rgba(0, 0, 0, 0.06);
    --shadow-lg: 0 10px 15px -3px rgba(0, 0, 0, 0.1), 0 4px 6px -2px rgba(0, 0, 0, 0.05);
    --shadow-xl: 0 20px 25px -5px rgba(0, 0, 0, 0.1), 0 10px 10px -5px rgba(0, 0, 0, 0.04);
}

html {
    font-size: 16px;
    scroll-behavior: smooth;
    -webkit-font-smoothing: antialiased;
    -moz-osx-font-smoothing: grayscale;
}

body {
    font-family: var(--font-body);
    line-height: 1.6;
    overflow-x: hidden;
    transition: background-color var(--transition-base), color var(--transition-base);
}

/* ============================================
   App Container & Layout
   ============================================ */

.app-container {
    display: grid;
    grid-template-columns: 1fr;
    grid-template-rows: auto 1fr;
    min-height: 100vh;
    position: relative;
    z-index: 1;
}

.background-canvas {
    position: fixed;
    top: 0;
    left: 0;
    width: 100%;
    height: 100%;
    z-index: 0;
    pointer-events: none;
    overflow: hidden;
}

#particlesCanvas {
    width: 100%;
    height: 100%;
    display: block;
}

/* ============================================
   Main Content Area
   ============================================ */

.main-content {
    position: relative;
    z-index: 1;
    padding: var(--spacing-xl);
    padding-top: calc(80px + var(--spacing-xl));
    padding-bottom: calc(var(--spacing-xl) + 20px);
    transition: padding var(--transition-base);
    min-height: calc(100vh - 80px);
}

.view-section {
    display: none;
    animation: fadeIn 0.4s ease-out;
}

.view-section.active {
    display: block;
}

@keyframes fadeIn {
    from {
        opacity: 0;
        transform: translateY(10px);
    }
    to {
        opacity: 1;
        transform: translateY(0);
    }
}

/* ============================================
   Typography
   ============================================ */

h1, h2, h3, h4, h5, h6 {
    font-family: var(--font-heading);
    font-weight: 600;
    line-height: 1.2;
}

h1 { font-size: 2.5rem; }
h2 { font-size: 2rem; }
h3 { font-size: 1.5rem; }
h4 { font-size: 1.25rem; }

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

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

/* ============================================
   Utility Classes
   ============================================ */

.container {
    max-width: 1400px;
    margin: 0 auto;
    padding: 0 var(--spacing-lg);
}

.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-width: 0;
}

/* ============================================
   Scrollbar Styling
   ============================================ */

::-webkit-scrollbar {
    width: 8px;
    height: 8px;
}

::-webkit-scrollbar-track {
    background: transparent;
}

::-webkit-scrollbar-thumb {
    background: var(--color-border);
    border-radius: var(--radius-full);
    transition: background var(--transition-fast);
}

::-webkit-scrollbar-thumb:hover {
    background: var(--color-text-muted);
}

/* ============================================
   Focus Styles (Accessibility)
   ============================================ */

*:focus-visible {
    outline: 2px solid var(--color-primary);
    outline-offset: 2px;
    border-radius: var(--radius-sm);
}

button:focus-visible,
input:focus-visible,
select:focus-visible,
textarea:focus-visible {
    outline: 2px solid var(--color-primary);
    outline-offset: 2px;
}

/* ============================================
   Responsive Base
   ============================================ */

@media (max-width: 768px) {
    html {
        font-size: 14px;
    }
    
    .main-content {
        padding: var(--spacing-md);
        padding-top: calc(70px + var(--spacing-md));
    }
    
    h1 { font-size: 2rem; }
    h2 { font-size: 1.75rem; }
    h3 { font-size: 1.25rem; }
}

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