/* ====================================
   Carbon Converter - Global Styles
   Brand Colors and Typography
   ==================================== */

:root {
    /* Primary Brand Colors */
    --primary: #ff914d;
    --primary-dark: #ff711a;
    --primary-light: #fff6ed;

    /* Status Colors */
    --success: #12b981;
    --error: #ef4444;
    --warning: #f59e0b;
    --info: #3b82f6;

    /* Text Colors */
    --text-primary: #1f2937;
    --text-secondary: #343a40;
    --text-light: #6b7280;
    --text-white: #ffffff;

    /* Background Colors */
    --bg-white: #ffffff;
    --bg-light: #f9fafb;
    --bg-gray: #f3f4f6;
    --bg-dark: #111827;

    /* Gradient */
    --gradient-primary: linear-gradient(135deg, #ff914d 0%, #ff711a 100%);
    --gradient-secondary: linear-gradient(135deg, #fff6ed 0%, #ffe8d1 100%);
    --gradient-success: linear-gradient(135deg, #12b981 0%, #059669 100%);
    --gradient-hero: linear-gradient(135deg, #fff6ed 0%, #fef3e7 50%, #ffefd9 100%);

    /* Spacing */
    --spacing-xs: 0.25rem;
    --spacing-sm: 0.5rem;
    --spacing-md: 1rem;
    --spacing-lg: 1.5rem;
    --spacing-xl: 2rem;
    --spacing-2xl: 3rem;
    --spacing-3xl: 4rem;

    /* Border Radius */
    --radius-sm: 0.375rem;
    --radius-md: 0.5rem;
    --radius-lg: 0.75rem;
    --radius-xl: 1rem;
    --radius-2xl: 1.5rem;
    --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);
    --shadow-primary: 0 10px 25px -5px rgba(255, 145, 77, 0.3);

    /* Transitions */
    --transition-fast: 150ms ease;
    --transition-base: 250ms ease;
    --transition-slow: 350ms ease;

    /* Typography */
    --font-sans: -apple-system, BlinkMacSystemFont, 'Segoe UI', Roboto, 'Helvetica Neue', Arial, sans-serif;
    --font-mono: 'SF Mono', Monaco, 'Cascadia Code', 'Courier New', monospace;
}

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

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

html {
    font-size: 16px;
    scroll-behavior: smooth;
}

body {
    font-family: var(--font-sans);
    color: var(--text-primary);
    background: var(--bg-light);
    line-height: 1.6;
    -webkit-font-smoothing: antialiased;
    -moz-osx-font-smoothing: grayscale;
}

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

h1, h2, h3, h4, h5, h6 {
    font-weight: 700;
    line-height: 1.2;
    margin-bottom: var(--spacing-md);
    color: var(--text-primary);
}

h1 { font-size: 2.5rem; }
h2 { font-size: 2rem; }
h3 { font-size: 1.75rem; }
h4 { font-size: 1.5rem; }
h5 { font-size: 1.25rem; }
h6 { font-size: 1rem; }

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

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

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

/* Ensure button links maintain their text color */
a.btn,
a.btn:hover,
a.btn:visited {
    text-decoration: none;
}

a.btn-primary,
a.btn-primary:hover,
a.btn-primary:visited {
    color: var(--text-white);
}

a.btn-secondary,
a.btn-secondary:hover,
a.btn-secondary:visited {
    color: var(--primary);
}

a.btn-outline {
    color: var(--text-secondary);
}

a.btn-outline:hover,
a.btn-outline:visited:hover {
    color: var(--primary);
}

/* ====================================
   Navigation
   ==================================== */

.navbar {
    background: var(--bg-white);
    box-shadow: var(--shadow-md);
    position: sticky;
    top: 0;
    z-index: 1000;
    transition: all var(--transition-base);
}

.nav-container {
    max-width: 1200px;
    margin: 0 auto;
    padding: var(--spacing-md) var(--spacing-lg);
    display: flex;
    justify-content: space-between;
    align-items: center;
}

.logo {
    font-size: 1.5rem;
    font-weight: 700;
    background: var(--gradient-primary);
    -webkit-background-clip: text;
    -webkit-text-fill-color: transparent;
    background-clip: text;
    display: flex;
    align-items: center;
    gap: var(--spacing-sm);
}

.logo-icon {
    font-size: 2rem;
}

.nav-menu {
    display: flex;
    list-style: none;
    gap: var(--spacing-xl);
    align-items: center;
}

.nav-link {
    color: var(--text-secondary);
    font-weight: 500;
    padding: var(--spacing-sm) var(--spacing-md);
    border-radius: var(--radius-md);
    transition: all var(--transition-fast);
}

.nav-link:hover {
    background: var(--primary-light);
    color: var(--primary);
}

.nav-link.active {
    background: var(--gradient-primary);
    color: var(--text-white);
}

.mobile-menu-toggle {
    display: none;
    background: none;
    border: none;
    font-size: 1.5rem;
    cursor: pointer;
    color: var(--text-primary);
}

/* ====================================
   Hero Section
   ==================================== */

.hero {
    background: var(--gradient-hero);
    padding: var(--spacing-3xl) var(--spacing-lg);
    text-align: center;
    position: relative;
    overflow: hidden;
}

.hero::before {
    content: '';
    position: absolute;
    top: -50%;
    right: -20%;
    width: 600px;
    height: 600px;
    background: radial-gradient(circle, rgba(255, 145, 77, 0.1) 0%, transparent 70%);
    border-radius: 50%;
}

.hero-content {
    max-width: 900px;
    margin: 0 auto;
    position: relative;
    z-index: 1;
}

.hero-title {
    font-size: 3rem;
    margin-bottom: var(--spacing-lg);
    background: var(--gradient-primary);
    -webkit-background-clip: text;
    -webkit-text-fill-color: transparent;
    background-clip: text;
}

.hero-subtitle {
    font-size: 1.25rem;
    color: var(--text-secondary);
    margin-bottom: var(--spacing-xl);
    line-height: 1.8;
}

.hero-icon {
    font-size: 4rem;
    margin-bottom: var(--spacing-lg);
}

/* ====================================
   Buttons
   ==================================== */

.btn {
    display: inline-flex;
    align-items: center;
    gap: var(--spacing-sm);
    padding: var(--spacing-md) var(--spacing-xl);
    border: none;
    border-radius: var(--radius-lg);
    font-weight: 600;
    font-size: 1rem;
    cursor: pointer;
    transition: all var(--transition-base);
    text-decoration: none;
    outline: none;
}

.btn-primary {
    background: var(--gradient-primary);
    color: var(--text-white);
    box-shadow: var(--shadow-primary);
}

.btn-primary:hover {
    transform: translateY(-2px);
    box-shadow: 0 15px 30px -8px rgba(255, 145, 77, 0.4);
    color: var(--text-white);
}

.btn-primary:active {
    transform: translateY(0);
}

.btn-secondary {
    background: var(--bg-white);
    color: var(--primary);
    border: 2px solid var(--primary);
}

.btn-secondary:hover {
    background: var(--primary-light);
    color: var(--primary);
}

.btn-success {
    background: var(--gradient-success);
    color: var(--text-white);
}

.btn-success:hover {
    transform: translateY(-2px);
    box-shadow: 0 10px 25px -5px rgba(18, 185, 129, 0.3);
    color: var(--text-white);
}

.btn-outline {
    background: transparent;
    color: var(--text-secondary);
    border: 2px solid var(--bg-gray);
}

.btn-outline:hover {
    border-color: var(--primary);
    color: var(--primary);
}

.btn-lg {
    padding: var(--spacing-lg) var(--spacing-2xl);
    font-size: 1.125rem;
}

.btn-sm {
    padding: var(--spacing-sm) var(--spacing-md);
    font-size: 0.875rem;
}

.btn:disabled {
    opacity: 0.6;
    cursor: not-allowed;
}

/* ====================================
   Cards
   ==================================== */

.card {
    background: var(--bg-white);
    border-radius: var(--radius-xl);
    padding: var(--spacing-xl);
    box-shadow: var(--shadow-md);
    transition: all var(--transition-base);
}

.card:hover {
    box-shadow: var(--shadow-xl);
    transform: translateY(-4px);
}

.card-header {
    display: flex;
    align-items: center;
    gap: var(--spacing-md);
    margin-bottom: var(--spacing-lg);
}

.card-icon {
    font-size: 2.5rem;
    background: var(--gradient-primary);
    -webkit-background-clip: text;
    -webkit-text-fill-color: transparent;
    background-clip: text;
}

.card-title {
    font-size: 1.5rem;
    margin-bottom: var(--spacing-sm);
}

.card-description {
    color: var(--text-light);
    font-size: 0.95rem;
}

/* ====================================
   Grid Layouts
   ==================================== */

.container {
    max-width: 1200px;
    margin: 0 auto;
    padding: 0 var(--spacing-lg);
}

.section {
    padding: var(--spacing-3xl) 0;
}

.section-title {
    text-align: center;
    margin-bottom: var(--spacing-2xl);
}

.grid {
    display: grid;
    gap: var(--spacing-xl);
}

.grid-2 {
    grid-template-columns: repeat(auto-fit, minmax(300px, 1fr));
}

.grid-3 {
    grid-template-columns: repeat(auto-fit, minmax(280px, 1fr));
}

.grid-4 {
    grid-template-columns: repeat(auto-fit, minmax(250px, 1fr));
}

/* ====================================
   Form Elements
   ==================================== */

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

.form-label {
    display: block;
    font-weight: 600;
    margin-bottom: var(--spacing-sm);
    color: var(--text-primary);
}

.form-input,
.form-select,
.form-textarea {
    width: 100%;
    padding: var(--spacing-md);
    border: 2px solid var(--bg-gray);
    border-radius: var(--radius-md);
    font-size: 1rem;
    font-family: var(--font-sans);
    transition: all var(--transition-fast);
    background: var(--bg-white);
}

.form-input:focus,
.form-select:focus,
.form-textarea:focus {
    outline: none;
    border-color: var(--primary);
    box-shadow: 0 0 0 3px rgba(255, 145, 77, 0.1);
}

.form-textarea {
    resize: vertical;
    min-height: 120px;
}

.form-help {
    font-size: 0.875rem;
    color: var(--text-light);
    margin-top: var(--spacing-sm);
}

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

/* ====================================
   Calculator Tool Styles
   ==================================== */

.calculator-container {
    max-width: 1000px;
    margin: 0 auto;
    padding: var(--spacing-xl);
}

.calculator-card {
    background: var(--bg-white);
    border-radius: var(--radius-xl);
    padding: var(--spacing-2xl);
    box-shadow: var(--shadow-lg);
}

.calculator-header {
    text-align: center;
    margin-bottom: var(--spacing-2xl);
    padding-bottom: var(--spacing-xl);
    border-bottom: 2px solid var(--bg-gray);
}

.calculator-icon {
    font-size: 4rem;
    margin-bottom: var(--spacing-md);
}

.input-row {
    display: grid;
    grid-template-columns: repeat(auto-fit, minmax(250px, 1fr));
    gap: var(--spacing-lg);
    margin-bottom: var(--spacing-lg);
}

.result-section {
    background: var(--gradient-hero);
    border-radius: var(--radius-lg);
    padding: var(--spacing-2xl);
    margin-top: var(--spacing-2xl);
    text-align: center;
}

.result-value {
    font-size: 3rem;
    font-weight: 700;
    background: var(--gradient-primary);
    -webkit-background-clip: text;
    -webkit-text-fill-color: transparent;
    background-clip: text;
    margin: var(--spacing-md) 0;
}

.result-label {
    font-size: 1.125rem;
    color: var(--text-secondary);
    margin-bottom: var(--spacing-sm);
}

.comparison-grid {
    display: grid;
    grid-template-columns: repeat(auto-fit, minmax(200px, 1fr));
    gap: var(--spacing-md);
    margin-top: var(--spacing-xl);
}

.comparison-item {
    background: var(--bg-white);
    padding: var(--spacing-md);
    border-radius: var(--radius-md);
    text-align: center;
}

.comparison-icon {
    font-size: 2rem;
    margin-bottom: var(--spacing-sm);
}

.comparison-value {
    font-weight: 700;
    color: var(--primary);
    margin-bottom: var(--spacing-xs);
}

.comparison-text {
    font-size: 0.875rem;
    color: var(--text-light);
}

/* ====================================
   Charts & Visualizations
   ==================================== */

.chart-container {
    background: var(--bg-white);
    border-radius: var(--radius-lg);
    padding: var(--spacing-xl);
    margin-top: var(--spacing-xl);
    box-shadow: var(--shadow-md);
}

.chart-title {
    font-size: 1.25rem;
    margin-bottom: var(--spacing-lg);
    text-align: center;
}

.progress-bar {
    width: 100%;
    height: 8px;
    background: var(--bg-gray);
    border-radius: var(--radius-full);
    overflow: hidden;
}

.progress-fill {
    height: 100%;
    background: var(--gradient-primary);
    border-radius: var(--radius-full);
    transition: width var(--transition-slow);
}

/* ====================================
   Alerts & Notifications
   ==================================== */

.alert {
    padding: var(--spacing-lg);
    border-radius: var(--radius-md);
    margin-bottom: var(--spacing-lg);
    display: flex;
    align-items: start;
    gap: var(--spacing-md);
}

.alert-success {
    background: rgba(18, 185, 129, 0.1);
    border-left: 4px solid var(--success);
    color: #047857;
}

.alert-error {
    background: rgba(239, 68, 68, 0.1);
    border-left: 4px solid var(--error);
    color: #b91c1c;
}

.alert-info {
    background: rgba(59, 130, 246, 0.1);
    border-left: 4px solid var(--info);
    color: #1e40af;
}

.alert-warning {
    background: rgba(245, 158, 11, 0.1);
    border-left: 4px solid var(--warning);
    color: #b45309;
}

/* ====================================
   Loading States
   ==================================== */

.loading {
    display: inline-block;
    width: 20px;
    height: 20px;
    border: 3px solid var(--bg-gray);
    border-top-color: var(--primary);
    border-radius: 50%;
    animation: spin 0.8s linear infinite;
}

@keyframes spin {
    to { transform: rotate(360deg); }
}

.skeleton {
    background: linear-gradient(90deg, var(--bg-gray) 25%, var(--bg-light) 50%, var(--bg-gray) 75%);
    background-size: 200% 100%;
    animation: loading 1.5s ease-in-out infinite;
    border-radius: var(--radius-md);
}

@keyframes loading {
    0% { background-position: 200% 0; }
    100% { background-position: -200% 0; }
}

/* ====================================
   Footer
   ==================================== */

.footer {
    background: var(--bg-dark);
    color: var(--text-white);
    padding: var(--spacing-2xl) var(--spacing-lg);
    margin-top: var(--spacing-3xl);
}

.footer-content {
    max-width: 1200px;
    margin: 0 auto;
    display: grid;
    grid-template-columns: repeat(auto-fit, minmax(250px, 1fr));
    gap: var(--spacing-xl);
}

.footer-section h3 {
    color: var(--text-white);
    margin-bottom: var(--spacing-md);
}

.footer-links {
    list-style: none;
}

.footer-links li {
    margin-bottom: var(--spacing-sm);
}

.footer-links a {
    color: #9ca3af;
    transition: color var(--transition-fast);
}

.footer-links a:hover {
    color: var(--primary);
}

.footer-bottom {
    text-align: center;
    padding-top: var(--spacing-xl);
    margin-top: var(--spacing-xl);
    border-top: 1px solid #374151;
    color: #9ca3af;
}

/* ====================================
   Responsive Design
   ==================================== */

@media (max-width: 768px) {
    html {
        font-size: 14px;
    }

    .hero-title {
        font-size: 2rem;
    }

    .hero-subtitle {
        font-size: 1rem;
    }

    .nav-menu {
        display: none;
        position: absolute;
        top: 100%;
        left: 0;
        right: 0;
        background: var(--bg-white);
        flex-direction: column;
        padding: var(--spacing-lg);
        box-shadow: var(--shadow-lg);
    }

    .nav-menu.active {
        display: flex;
    }

    .mobile-menu-toggle {
        display: block;
    }

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

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

    .result-value {
        font-size: 2rem;
    }
}

@media (max-width: 480px) {
    .container {
        padding: 0 var(--spacing-md);
    }

    .hero {
        padding: var(--spacing-2xl) var(--spacing-md);
    }

    .section {
        padding: var(--spacing-2xl) 0;
    }
}

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

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

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

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

.hidden { display: none; }
.visible { display: block; }

.flex { display: flex; }
.flex-center { display: flex; align-items: center; justify-content: center; }
.flex-between { display: flex; align-items: center; justify-content: space-between; }
.flex-col { flex-direction: column; }
.gap-1 { gap: var(--spacing-sm); }
.gap-2 { gap: var(--spacing-md); }
.gap-3 { gap: var(--spacing-lg); }

.font-bold { font-weight: 700; }
.font-semibold { font-weight: 600; }
.font-medium { font-weight: 500; }

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

.bg-primary { background: var(--primary); }
.bg-success { background: var(--success); }
.bg-white { background: var(--bg-white); }
.bg-light { background: var(--bg-light); }