/* ================================================
   CalculatorMax - Main Stylesheet
   Design System & Core Styles
   ================================================ */

/* Root Variables */
:root {
    /* Colors */
    --primary: #3b82f6;
    --primary-dark: #2563eb;
    --primary-light: #eff6ff;
    --secondary: #8b5cf6;
    --success: #10b981;
    --warning: #f59e0b;
    --danger: #ef4444;
    --gray-50: #f9fafb;
    --gray-100: #f3f4f6;
    --gray-200: #e5e7eb;
    --gray-300: #d1d5db;
    --gray-400: #9ca3af;
    --gray-500: #6b7280;
    --gray-600: #4b5563;
    --gray-700: #374151;
    --gray-800: #1f2937;
    --gray-900: #111827;
    
    /* Typography */
    --font-sans: -apple-system, BlinkMacSystemFont, 'Segoe UI', 'Roboto', 'Oxygen', 'Ubuntu', 'Cantarell', sans-serif;
    --font-mono: 'Monaco', 'Courier New', monospace;
    --base-font-size: 16px;
    
    /* Spacing */
    --spacing-xs: 0.25rem;
    --spacing-sm: 0.5rem;
    --spacing-md: 1rem;
    --spacing-lg: 1.5rem;
    --spacing-xl: 2rem;
    --spacing-2xl: 3rem;
    
    /* Border Radius */
    --radius-sm: 0.375rem;
    --radius-md: 0.5rem;
    --radius-lg: 0.75rem;
    --radius-full: 9999px;
    
    /* Transitions */
    --transition-fast: 0.15s ease;
    --transition-base: 0.2s ease;
    --transition-slow: 0.3s ease;
    
    /* 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);
}

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

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

body {
    font-family: var(--font-sans);
    color: var(--gray-700);
    background: white;
    line-height: 1.6;
    min-height: 100vh;
    display: flex;
    flex-direction: column;
}

main {
    flex: 1;
}

/* Typography */
h1, h2, h3, h4, h5, h6 {
    font-weight: 700;
    line-height: 1.25;
    color: var(--gray-900);
    margin: 1.5rem 0 0.75rem 0;
}

h1 {
    font-size: 2.25rem;
    margin-top: 0;
}

h2 {
    font-size: 1.875rem;
}

h3 {
    font-size: 1.5rem;
}

h4 {
    font-size: 1.25rem;
}

h5 {
    font-size: 1.125rem;
}

h6 {
    font-size: 1rem;
}

p {
    margin: 0 0 1rem 0;
    line-height: 1.7;
}

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

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

ul, ol {
    margin: 0 0 1rem 0;
    padding-left: 1.75rem;
}

li {
    margin: 0.5rem 0;
}

code {
    font-family: var(--font-mono);
    background: var(--gray-100);
    padding: 0.25rem 0.5rem;
    border-radius: var(--radius-sm);
    font-size: 0.875em;
    color: var(--danger);
}

pre {
    background: var(--gray-900);
    color: #e5e7eb;
    padding: 1rem;
    border-radius: var(--radius-md);
    overflow-x: auto;
    font-size: 0.875rem;
    line-height: 1.5;
    margin: 0 0 1rem 0;
}

pre code {
    background: none;
    padding: 0;
    color: inherit;
}

/* Container */
.container {
    width: 100%;
    max-width: 1200px;
    margin: 0 auto;
    padding: 0 1.5rem;
}

@media (max-width: 768px) {
    .container {
        padding: 0 1rem;
    }
}

/* Buttons */
button, .button {
    display: inline-flex;
    align-items: center;
    justify-content: center;
    padding: 0.75rem 1.5rem;
    background: var(--primary);
    color: white;
    border: 2px solid var(--primary);
    border-radius: var(--radius-md);
    font-weight: 600;
    font-size: 1rem;
    cursor: pointer;
    transition: all var(--transition-base);
    font-family: inherit;
    text-decoration: none;
    user-select: none;
}

button:hover, .button:hover {
    background: var(--primary-dark);
    border-color: var(--primary-dark);
}

button:active, .button:active {
    transform: scale(0.98);
}

button:disabled, .button:disabled {
    opacity: 0.5;
    cursor: not-allowed;
}

.button-secondary {
    background: var(--gray-200);
    border-color: var(--gray-300);
    color: var(--gray-900);
}

.button-secondary:hover {
    background: var(--gray-300);
    border-color: var(--gray-400);
}

.button-ghost {
    background: transparent;
    border-color: var(--primary);
    color: var(--primary);
}

.button-ghost:hover {
    background: var(--primary-light);
    border-color: var(--primary-dark);
    color: var(--primary-dark);
}

.button-small {
    padding: 0.5rem 1rem;
    font-size: 0.875rem;
}

.button-large {
    padding: 1rem 2rem;
    font-size: 1.125rem;
}

.button-full {
    width: 100%;
}

/* Form Elements */
input, textarea, select {
    display: block;
    width: 100%;
    padding: 0.75rem 1rem;
    border: 1px solid var(--gray-300);
    border-radius: var(--radius-md);
    font-family: inherit;
    font-size: 1rem;
    transition: all var(--transition-base);
    background: white;
}

input:focus, textarea:focus, select:focus {
    outline: none;
    border-color: var(--primary);
    box-shadow: 0 0 0 3px rgba(59, 130, 246, 0.1);
}

input[type="checkbox"], input[type="radio"] {
    width: auto;
    display: inline-block;
    margin-right: 0.5rem;
}

label {
    display: block;
    margin-bottom: 0.5rem;
    font-weight: 600;
    color: var(--gray-900);
}

.form-group {
    margin-bottom: 1.5rem;
}

.form-error {
    color: var(--danger);
    font-size: 0.875rem;
    margin-top: 0.25rem;
}

input.error, textarea.error, select.error {
    border-color: var(--danger);
}

/* Cards */
.card {
    background: white;
    border: 1px solid var(--gray-200);
    border-radius: var(--radius-lg);
    padding: 1.5rem;
    transition: all var(--transition-base);
}

.card:hover {
    border-color: var(--primary);
    box-shadow: var(--shadow-lg);
}

/* Alerts */
.alert {
    padding: 1rem 1.5rem;
    border-radius: var(--radius-md);
    margin: 1rem 0;
    border-left: 4px solid;
}

.alert-info {
    background: #dbeafe;
    border-color: var(--primary);
    color: #1e40af;
}

.alert-success {
    background: #dcfce7;
    border-color: var(--success);
    color: #166534;
}

.alert-warning {
    background: #fef3c7;
    border-color: var(--warning);
    color: #78350f;
}

.alert-error {
    background: #fee2e2;
    border-color: var(--danger);
    color: #7f1d1d;
}

/* Utilities */
.text-center {
    text-align: center;
}

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

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

.text-small {
    font-size: 0.875rem;
}

.text-large {
    font-size: 1.125rem;
}

.font-bold {
    font-weight: 700;
}

.font-semibold {
    font-weight: 600;
}

.mt-1 { margin-top: var(--spacing-md); }
.mt-2 { margin-top: var(--spacing-lg); }
.mt-3 { margin-top: var(--spacing-xl); }

.mb-1 { margin-bottom: var(--spacing-md); }
.mb-2 { margin-bottom: var(--spacing-lg); }
.mb-3 { margin-bottom: var(--spacing-xl); }

.p-1 { padding: var(--spacing-md); }
.p-2 { padding: var(--spacing-lg); }
.p-3 { padding: var(--spacing-xl); }

.hidden {
    display: none !important;
}

.visible {
    display: block !important;
}

/* Skip to content link */
.skip-to-content {
    position: absolute;
    top: -40px;
    left: 0;
    background: var(--primary);
    color: white;
    padding: 0.75rem 1.5rem;
    text-decoration: none;
    z-index: 100;
}

.skip-to-content:focus {
    top: 0;
}

/* Responsive Images */
img {
    max-width: 100%;
    height: auto;
    display: block;
}

/* Responsive Video */
.video-container {
    position: relative;
    width: 100%;
    padding-bottom: 56.25%;
    height: 0;
    overflow: hidden;
}

.video-container iframe {
    position: absolute;
    top: 0;
    left: 0;
    width: 100%;
    height: 100%;
    border: none;
}

/* Accessibility */
:focus-visible {
    outline: 2px solid var(--primary);
    outline-offset: 2px;
}

/* Print Styles */
@media print {
    body {
        background: white;
    }
    
    .no-print {
        display: none !important;
    }
    
    a {
        text-decoration: underline;
    }
    
    h1, h2, h3 {
        page-break-after: avoid;
    }
    
    p {
        widows: 3;
        orphans: 3;
    }
}

/* Dark mode support (optional) */
@media (prefers-color-scheme: dark) {
    body {
        background: var(--gray-900);
        color: var(--gray-100);
    }
    
    h1, h2, h3, h4, h5, h6 {
        color: white;
    }
    
    .card {
        background: var(--gray-800);
        border-color: var(--gray-700);
    }
    
    input, textarea, select {
        background: var(--gray-800);
        border-color: var(--gray-700);
        color: white;
    }
}