/* CalcuTools - Classic & Elegant Design */

:root {
    --color-primary: #1a365d;
    --color-primary-light: #2c5282;
    --color-primary-dark: #153e75;
    --color-secondary: #718096;
    --color-accent: #e53e3e;
    --color-success: #38a169;
    --color-warning: #d69e2e;
    
    --color-text-primary: #2d3748;
    --color-text-secondary: #4a5568;
    --color-text-muted: #718096;
    --color-text-light: #a0aec0;
    
    --color-background: #ffffff;
    --color-surface: #f7fafc;
    --color-surface-raised: #ffffff;
    --color-border: #e2e8f0;
    --color-border-light: #f1f5f9;
    --color-border-focus: #3182ce;
    
    --shadow-sm: 0 1px 2px 0 rgba(0, 0, 0, 0.05);
    --shadow: 0 1px 3px 0 rgba(0, 0, 0, 0.1), 0 1px 2px 0 rgba(0, 0, 0, 0.06);
    --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);
    
    --radius-sm: 4px;
    --radius: 6px;
    --radius-md: 8px;
    --radius-lg: 12px;
    
    --font-family-serif: "Charter", "Georgia", "Times New Roman", serif;
    --font-family-sans: "Inter", -apple-system, BlinkMacSystemFont, "Segoe UI", Roboto, sans-serif;
    --font-family-mono: "SF Mono", "Monaco", "Inconsolata", "Roboto Mono", monospace;
    
    --spacing-xs: 4px;
    --spacing-sm: 8px;
    --spacing: 16px;
    --spacing-md: 24px;
    --spacing-lg: 32px;
    --spacing-xl: 48px;
    --spacing-2xl: 64px;
    
    --transition: all 0.2s cubic-bezier(0.4, 0, 0.2, 1);
    --transition-slow: all 0.3s cubic-bezier(0.4, 0, 0.2, 1);
}

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

html {
    font-size: 16px;
    line-height: 1.6;
    scroll-behavior: smooth;
    -webkit-font-smoothing: antialiased;
    -moz-osx-font-smoothing: grayscale;
}

body {
    font-family: var(--font-family-sans);
    color: var(--color-text-primary);
    background: var(--color-background);
    min-height: 100vh;
    display: flex;
    flex-direction: column;
}

/* Typography */
.font-serif { font-family: var(--font-family-serif); }
.font-sans { font-family: var(--font-family-sans); }
.font-mono { font-family: var(--font-family-mono); }

h1, h2, h3, h4, h5, h6 {
    font-weight: 600;
    line-height: 1.3;
    letter-spacing: -0.025em;
    color: var(--color-text-primary);
    margin-bottom: var(--spacing);
}

h1 { font-size: 2.5rem; font-weight: 700; }
h2 { font-size: 2rem; }
h3 { font-size: 1.5rem; }
h4 { font-size: 1.25rem; }
h5 { font-size: 1.125rem; }
h6 { font-size: 1rem; }

p {
    margin-bottom: var(--spacing);
    color: var(--color-text-secondary);
}

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

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

/* Layout Components */
.container {
    max-width: 1200px;
    margin: 0 auto;
    padding: 0 var(--spacing-md);
}

.container-narrow {
    max-width: 768px;
    margin: 0 auto;
    padding: 0 var(--spacing-md);
}

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

/* Header */
.site-header {
    background: var(--color-surface-raised);
    border-bottom: 1px solid var(--color-border);
    position: sticky;
    top: 0;
    z-index: 100;
    box-shadow: var(--shadow-sm);
}

.header-content {
    display: flex;
    align-items: center;
    justify-content: space-between;
    height: 64px;
}

.site-logo {
    font-size: 1.375rem;
    font-weight: 700;
    color: var(--color-primary);
    letter-spacing: -0.025em;
    transition: var(--transition);
}

.site-logo:hover {
    color: var(--color-primary-dark);
    text-decoration: none;
}

.main-nav {
    display: flex;
    align-items: center;
    gap: var(--spacing-lg);
}

.nav-link {
    font-weight: 500;
    color: var(--color-text-secondary);
    transition: var(--transition);
    position: relative;
    padding: var(--spacing-sm) 0;
}

.nav-link:hover {
    color: var(--color-primary);
    text-decoration: none;
}

.nav-link.active {
    color: var(--color-primary);
}

.nav-link.active::after {
    content: '';
    position: absolute;
    bottom: -1px;
    left: 0;
    right: 0;
    height: 2px;
    background: var(--color-primary);
}

/* Main Content */
.site-main {
    flex: 1;
    padding: var(--spacing-2xl) 0;
}

/* Hero Section */
.hero {
    text-align: center;
    padding: var(--spacing-2xl) var(--spacing-md);
    margin-bottom: var(--spacing-2xl);
    background: linear-gradient(135deg, var(--color-surface) 0%, var(--color-background) 100%);
    border-radius: var(--radius-lg);
    border: 1px solid var(--color-border-light);
}

.hero-title {
    font-size: 3rem;
    font-weight: 800;
    margin-bottom: var(--spacing);
    background: linear-gradient(135deg, var(--color-primary) 0%, var(--color-primary-light) 100%);
    -webkit-background-clip: text;
    -webkit-text-fill-color: transparent;
    background-clip: text;
}

.hero-subtitle {
    font-size: 1.25rem;
    color: var(--color-text-secondary);
    max-width: 600px;
    margin: 0 auto var(--spacing-lg);
    line-height: 1.6;
}

/* Cards */
.card {
    background: var(--color-surface-raised);
    border: 1px solid var(--color-border);
    border-radius: var(--radius-md);
    box-shadow: var(--shadow);
    overflow: hidden;
    transition: var(--transition);
    margin-bottom: var(--spacing-lg);
}

.card:hover {
    box-shadow: var(--shadow-md);
    border-color: var(--color-border-focus);
}

.card-header {
    padding: var(--spacing-lg) var(--spacing-md) var(--spacing-md);
    border-bottom: 1px solid var(--color-border-light);
    background: var(--color-surface);
}

.card-body {
    padding: var(--spacing-lg) var(--spacing-lg) var(--spacing-xl);
}

.card-title {
    font-size: 1.5rem;
    font-weight: 600;
    margin-bottom: var(--spacing-sm);
    color: var(--color-text-primary);
    line-height: 1.3;
}

.card-description {
    color: var(--color-text-secondary);
    margin-bottom: 0;
    line-height: 1.5;
}

.card-compact .card-header {
    padding: var(--spacing-md) var(--spacing) var(--spacing-sm);
}

.card-compact .card-body {
    padding: var(--spacing-sm) var(--spacing) var(--spacing-md);
}

/* Better spacing for lists inside cards */
.card-body ul {
    margin-bottom: var(--spacing-md);
    padding-left: var(--spacing-lg);
    padding-right: var(--spacing-sm);
}

.card-body ul li {
    margin-bottom: var(--spacing-sm);
    line-height: 1.6;
    padding-right: var(--spacing-sm);
}

.card-body ul li a {
    display: block;
    padding: var(--spacing-xs) 0;
    transition: var(--transition);
}

.card-body ul li a:hover {
    padding-left: var(--spacing-sm);
}

.card-body ol {
    margin-bottom: var(--spacing-md);
    padding-left: var(--spacing-lg);
    padding-right: var(--spacing-sm);
}

.card-body ol li {
    margin-bottom: var(--spacing-sm);
    line-height: 1.6;
    padding-left: var(--spacing-sm);
    padding-right: var(--spacing-sm);
}

.card-body h4 {
    margin-top: var(--spacing-md);
    margin-bottom: var(--spacing-sm);
    font-size: 1.125rem;
    font-weight: 600;
    color: var(--color-text-primary);
}

.card-body h4:first-child {
    margin-top: 0;
}

.card-body p {
    margin-bottom: var(--spacing);
    line-height: 1.6;
}

.card-body p:last-child {
    margin-bottom: 0;
}

/* Forms */
.form-group {
    margin-bottom: var(--spacing-lg);
}

.form-group:last-child {
    margin-bottom: 0;
}

.form-label {
    display: block;
    font-weight: 500;
    margin-bottom: var(--spacing-sm);
    color: var(--color-text-primary);
    font-size: 0.875rem;
    text-transform: uppercase;
    letter-spacing: 0.05em;
}

.form-input {
    width: 100%;
    padding: var(--spacing) var(--spacing);
    border: 1px solid var(--color-border);
    border-radius: var(--radius);
    font-size: 1rem;
    font-family: var(--font-family-mono);
    background: var(--color-background);
    transition: var(--transition);
    appearance: none;
}

.form-input:focus {
    outline: none;
    border-color: var(--color-border-focus);
    box-shadow: 0 0 0 3px rgba(49, 130, 206, 0.1);
}

.form-input::placeholder {
    color: var(--color-text-light);
}

.form-input-lg {
    padding: var(--spacing-md) var(--spacing);
    font-size: 1.125rem;
}

/* Buttons */
.btn {
    display: inline-flex;
    align-items: center;
    justify-content: center;
    padding: var(--spacing) var(--spacing-md);
    border: 1px solid transparent;
    border-radius: var(--radius);
    font-size: 0.875rem;
    font-weight: 500;
    text-transform: uppercase;
    letter-spacing: 0.05em;
    cursor: pointer;
    transition: var(--transition);
    text-decoration: none;
    min-height: 44px;
    gap: var(--spacing-sm);
}

.btn:focus {
    outline: none;
    box-shadow: 0 0 0 3px rgba(49, 130, 206, 0.1);
}

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

.btn-primary:hover {
    background: var(--color-primary-dark);
    border-color: var(--color-primary-dark);
    color: white;
    text-decoration: none;
    transform: translateY(-1px);
    box-shadow: var(--shadow-md);
}

.btn-secondary {
    background: var(--color-background);
    color: var(--color-text-primary);
    border-color: var(--color-border);
}

.btn-secondary:hover {
    background: var(--color-surface);
    border-color: var(--color-border);
    color: var(--color-text-primary);
    text-decoration: none;
}

.btn:disabled {
    opacity: 0.6;
    cursor: not-allowed;
    pointer-events: none;
}

.btn-lg {
    padding: var(--spacing-md) var(--spacing-lg);
    font-size: 1rem;
    min-height: 52px;
}

.btn-block {
    width: 100%;
}

.btn + .btn {
    margin-left: 0;
}

/* Button groups within forms */
.form-group + .grid {
    margin-top: var(--spacing-lg);
}

/* Calculator Specific */
.calculators-section {
    margin-bottom: var(--spacing-2xl);
}

.calculators-section .card {
    max-width: none;
}
.calculator-tabs {
    display: flex;
    border-bottom: 1px solid var(--color-border);
    margin-bottom: var(--spacing-lg);
    overflow-x: auto;
    scrollbar-width: none;
    -ms-overflow-style: none;
}

.calculator-tabs::-webkit-scrollbar {
    display: none;
}

.tab-button {
    padding: var(--spacing) var(--spacing-md);
    border: none;
    background: none;
    color: var(--color-text-secondary);
    font-size: 0.875rem;
    font-weight: 500;
    text-transform: uppercase;
    letter-spacing: 0.05em;
    cursor: pointer;
    border-bottom: 2px solid transparent;
    transition: var(--transition);
    white-space: nowrap;
    min-height: 44px;
}

.tab-button:hover {
    color: var(--color-primary);
    background: var(--color-surface);
}

.tab-button.active {
    color: var(--color-primary);
    border-bottom-color: var(--color-primary);
}

.tab-content {
    display: none;
}

.tab-content.active {
    display: block;
}

/* Results Display */
.result-display {
    background: linear-gradient(135deg, var(--color-success) 0%, #48bb78 100%);
    color: white;
    text-align: center;
    padding: var(--spacing-lg);
    border-radius: var(--radius-md);
    margin-top: var(--spacing-md);
    box-shadow: var(--shadow-md);
}

.result-value {
    font-size: 2.5rem;
    font-weight: 800;
    font-family: var(--font-family-mono);
    margin-bottom: var(--spacing-sm);
    text-shadow: 0 2px 4px rgba(0, 0, 0, 0.1);
}

.result-description {
    font-size: 1.125rem;
    opacity: 0.95;
    font-weight: 500;
}

/* Grid System */
.grid {
    display: grid;
    gap: var(--spacing-md);
}

.grid-1 { grid-template-columns: 1fr; }
.grid-2 { grid-template-columns: repeat(2, 1fr); }
.grid-3 { grid-template-columns: repeat(3, 1fr); }
.grid-4 { grid-template-columns: repeat(4, 1fr); }

.grid-auto {
    grid-template-columns: repeat(auto-fit, minmax(280px, 1fr));
}

/* Content Sections */
.section {
    margin-bottom: var(--spacing-2xl);
}

.section:first-child {
    margin-top: 0;
}

.section:last-child {
    margin-bottom: var(--spacing-xl);
}

.section-header {
    text-align: center;
    margin-bottom: var(--spacing-xl);
}

.section-title {
    font-size: 2rem;
    font-weight: 700;
    margin-bottom: var(--spacing-md);
    line-height: 1.2;
}

.section-description {
    font-size: 1.125rem;
    color: var(--color-text-secondary);
    max-width: 600px;
    margin: 0 auto;
    line-height: 1.6;
}

/* Breadcrumbs */
.breadcrumb {
    display: flex;
    align-items: center;
    gap: var(--spacing-sm);
    margin-bottom: var(--spacing-xl);
    font-size: 0.875rem;
    color: var(--color-text-muted);
    padding-bottom: var(--spacing-sm);
}

.breadcrumb-separator {
    color: var(--color-text-light);
}

.breadcrumb a {
    color: var(--color-primary);
    font-weight: 500;
}

/* Footer */
.site-footer {
    background: var(--color-surface);
    border-top: 1px solid var(--color-border);
    padding: var(--spacing-2xl) 0 var(--spacing-xl);
    margin-top: auto;
}

.footer-content {
    text-align: center;
    color: var(--color-text-muted);
}

.footer-nav {
    display: flex;
    justify-content: center;
    gap: var(--spacing-xl);
    margin-bottom: var(--spacing-lg);
    flex-wrap: wrap;
}

.footer-nav a {
    color: var(--color-text-secondary);
    font-weight: 500;
    font-size: 0.9rem;
    transition: var(--transition);
}

.footer-nav a:hover {
    color: var(--color-primary);
    text-decoration: none;
}

.footer-copyright {
    font-size: 0.875rem;
    color: var(--color-text-light);
    line-height: 1.5;
}

.footer-copyright p {
    margin: 0;
}

/* Utility Classes */
.text-center { text-align: center; }
.text-left { text-align: left; }
.text-right { text-align: right; }

.text-primary { color: var(--color-primary); }
.text-secondary { color: var(--color-text-secondary); }
.text-muted { color: var(--color-text-muted); }

.bg-surface { background: var(--color-surface); }
.bg-primary { background: var(--color-primary); }

.border-top { border-top: 1px solid var(--color-border); }
.border-bottom { border-bottom: 1px solid var(--color-border); }

.mt-0 { margin-top: 0; }
.mt-1 { margin-top: var(--spacing-sm); }
.mt-2 { margin-top: var(--spacing); }
.mt-3 { margin-top: var(--spacing-md); }
.mt-4 { margin-top: var(--spacing-lg); }
.mt-5 { margin-top: var(--spacing-xl); }

.mb-0 { margin-bottom: 0; }
.mb-1 { margin-bottom: var(--spacing-sm); }
.mb-2 { margin-bottom: var(--spacing); }
.mb-3 { margin-bottom: var(--spacing-md); }
.mb-4 { margin-bottom: var(--spacing-lg); }
.mb-5 { margin-bottom: var(--spacing-xl); }

.my-0 { margin-top: 0; margin-bottom: 0; }
.my-1 { margin-top: var(--spacing-sm); margin-bottom: var(--spacing-sm); }
.my-2 { margin-top: var(--spacing); margin-bottom: var(--spacing); }
.my-3 { margin-top: var(--spacing-md); margin-bottom: var(--spacing-md); }
.my-4 { margin-top: var(--spacing-lg); margin-bottom: var(--spacing-lg); }
.my-5 { margin-top: var(--spacing-xl); margin-bottom: var(--spacing-xl); }

.p-0 { padding: 0; }
.p-1 { padding: var(--spacing-sm); }
.p-2 { padding: var(--spacing); }
.p-3 { padding: var(--spacing-md); }
.p-4 { padding: var(--spacing-lg); }

/* Responsive Design */
@media (max-width: 1024px) {
    .grid-3 {
        grid-template-columns: repeat(2, 1fr);
    }
}

@media (max-width: 768px) {
    :root {
        --spacing-2xl: 48px;
        --spacing-xl: 32px;
    }
    
    .container,
    .container-narrow,
    .container-wide {
        padding: 0 var(--spacing);
    }
    
    .hero {
        padding: var(--spacing-xl) var(--spacing);
        margin-bottom: var(--spacing-xl);
    }
    
    .hero-title {
        font-size: 2.5rem;
    }
    
    .hero-subtitle {
        font-size: 1.125rem;
    }
    
    .grid-2 {
        grid-template-columns: 1fr;
        gap: var(--spacing);
    }
    
    .grid-3 {
        grid-template-columns: 1fr;
        gap: var(--spacing);
    }
    
    .grid-4 {
        grid-template-columns: repeat(2, 1fr);
        gap: var(--spacing);
    }
    
    .main-nav {
        gap: var(--spacing);
    }
    
    .footer-nav {
        gap: var(--spacing-md);
    }
    
    .calculator-tabs {
        gap: 0;
    }
    
    .tab-button {
        padding: var(--spacing-sm) var(--spacing);
        font-size: 0.75rem;
    }
    
    .result-value {
        font-size: 2rem;
    }
    
    .card {
        margin-bottom: var(--spacing-md);
    }
    
    .card-header,
    .card-body {
        padding: var(--spacing);
    }
    
    .section-title {
        font-size: 1.75rem;
    }
}

@media (max-width: 480px) {
    .hero {
        padding: var(--spacing-lg) 0;
        margin-bottom: var(--spacing-lg);
    }
    
    .hero-title {
        font-size: 2rem;
    }
    
    .site-main {
        padding: var(--spacing-lg) 0;
    }
    
    h1 { font-size: 2rem; }
    h2 { font-size: 1.75rem; }
    h3 { font-size: 1.375rem; }
}

/* Loading and State Classes */
.loading {
    opacity: 0.6;
    pointer-events: none;
    position: relative;
}

.loading::after {
    content: '';
    position: absolute;
    top: 50%;
    left: 50%;
    width: 20px;
    height: 20px;
    margin: -10px 0 0 -10px;
    border: 2px solid var(--color-border);
    border-top-color: var(--color-primary);
    border-radius: 50%;
    animation: spin 1s linear infinite;
}

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

.error-message {
    color: var(--color-accent);
    font-size: 0.875rem;
    margin-top: var(--spacing-sm);
    font-weight: 500;
}

.success-message {
    color: var(--color-success);
    font-size: 0.875rem;
    margin-top: var(--spacing-sm);
    font-weight: 500;
}

/* Print Styles */
@media print {
    .site-header,
    .site-footer,
    .calculator-tabs,
    .btn {
        display: none;
    }
    
    .card {
        border: 1px solid #000;
        box-shadow: none;
    }
    
    .result-display {
        background: none;
        color: #000;
        border: 2px solid #000;
    }
}