/* ============================================
   TEMPERATURE CONVERTER - MODERN DESIGN
   ============================================ */

/* CSS Variables for Theme */
:root {
    /* Temperature Colors */
    --color-cold: #3b82f6;
    --color-cool: #06b6d4;
    --color-moderate: #10b981;
    --color-warm: #f59e0b;
    --color-hot: #ef4444;

    /* Light Theme */
    --bg-primary: #f8fafc;
    --bg-secondary: #ffffff;
    --bg-overlay: linear-gradient(135deg, #667eea 0%, #764ba2 100%);
    --text-primary: #1e293b;
    --text-secondary: #64748b;
    --shadow: rgba(0, 0, 0, 0.1);
    --shadow-lg: rgba(0, 0, 0, 0.15);
    --border: rgba(0, 0, 0, 0.1);
}

[data-theme="dark"] {
    /* Dark Theme */
    --bg-primary: #0f172a;
    --bg-secondary: #1e293b;
    --bg-overlay: linear-gradient(135deg, #434343 0%, #000000 100%);
    --text-primary: #e2e8f0;
    --text-secondary: #94a3b8;
    --shadow: rgba(0, 0, 0, 0.3);
    --shadow-lg: rgba(0, 0, 0, 0.5);
    --border: rgba(255, 255, 255, 0.1);
}

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

body {
    font-family: -apple-system, BlinkMacSystemFont, 'Segoe UI', 'Roboto', 'Oxygen',
        'Ubuntu', 'Cantarell', 'Fira Sans', 'Droid Sans', 'Helvetica Neue',
        sans-serif;
    background-color: var(--bg-primary);
    color: var(--text-primary);
    line-height: 1.6;
    min-height: 100vh;
    position: relative;
    overflow-x: hidden;
    transition: background-color 0.3s ease, color 0.3s ease;
}

/* Background Overlay with Gradient */
.background-overlay {
    position: fixed;
    top: 0;
    left: 0;
    right: 0;
    bottom: 0;
    background: var(--bg-overlay);
    opacity: 0.05;
    z-index: -1;
    transition: opacity 0.5s ease;
}

body.temp-cold .background-overlay {
    background: linear-gradient(135deg, var(--color-cold) 0%, var(--color-cool) 100%);
    opacity: 0.15;
}

body.temp-moderate .background-overlay {
    background: linear-gradient(135deg, var(--color-moderate) 0%, var(--color-cool) 100%);
    opacity: 0.15;
}

body.temp-warm .background-overlay {
    background: linear-gradient(135deg, var(--color-warm) 0%, var(--color-moderate) 100%);
    opacity: 0.15;
}

body.temp-hot .background-overlay {
    background: linear-gradient(135deg, var(--color-hot) 0%, var(--color-warm) 100%);
    opacity: 0.15;
}

/* Container */
.container {
    max-width: 1200px;
    margin: 0 auto;
    padding: clamp(1rem, 3vw, 2rem);
    position: relative;
    z-index: 1;
}

/* Header */
.header {
    text-align: center;
    margin-bottom: clamp(2rem, 5vw, 3rem);
    animation: fadeInDown 0.6s ease;
}

.header h1 {
    font-size: clamp(2rem, 5vw, 3rem);
    font-weight: 700;
    margin-bottom: 0.5rem;
    background: linear-gradient(135deg, var(--color-cool), var(--color-warm));
    -webkit-background-clip: text;
    -webkit-text-fill-color: transparent;
    background-clip: text;
}

.subtitle {
    font-size: clamp(0.875rem, 2vw, 1.125rem);
    color: var(--text-secondary);
}

/* Converter Section */
.converter-section {
    background: var(--bg-secondary);
    border-radius: 24px;
    padding: clamp(1.5rem, 4vw, 2.5rem);
    box-shadow: 0 10px 40px var(--shadow-lg);
    margin-bottom: 2rem;
    animation: fadeInUp 0.6s ease;
    backdrop-filter: blur(10px);
    border: 1px solid var(--border);
}

.converter-grid {
    display: grid;
    grid-template-columns: repeat(auto-fit, minmax(250px, 1fr));
    gap: 1.5rem;
    margin-bottom: 2rem;
}

/* Converter Card */
.converter-card {
    background: var(--bg-primary);
    border-radius: 16px;
    padding: 1.5rem;
    border: 2px solid var(--border);
    transition: all 0.3s ease;
    position: relative;
    overflow: hidden;
}

.converter-card::before {
    content: '';
    position: absolute;
    top: 0;
    left: 0;
    right: 0;
    height: 4px;
    background: linear-gradient(90deg, var(--color-cool), var(--color-warm));
    transform: scaleX(0);
    transition: transform 0.3s ease;
}

.converter-card:focus-within::before {
    transform: scaleX(1);
}

.converter-card:hover {
    transform: translateY(-4px);
    box-shadow: 0 8px 24px var(--shadow);
    border-color: var(--color-moderate);
}

.unit-label {
    display: flex;
    align-items: center;
    gap: 0.5rem;
    font-size: 1rem;
    font-weight: 600;
    margin-bottom: 0.75rem;
    color: var(--text-primary);
}

.unit-icon {
    font-size: 1.5rem;
}

.temp-input {
    width: 100%;
    padding: 1rem;
    font-size: 1.25rem;
    font-weight: 600;
    border: 2px solid var(--border);
    border-radius: 12px;
    background: var(--bg-secondary);
    color: var(--text-primary);
    transition: all 0.3s ease;
    outline: none;
}

.temp-input:focus {
    border-color: var(--color-moderate);
    box-shadow: 0 0 0 4px rgba(16, 185, 129, 0.1);
}

.temp-input::placeholder {
    color: var(--text-secondary);
    opacity: 0.5;
}

/* Remove number input arrows */
.temp-input::-webkit-outer-spin-button,
.temp-input::-webkit-inner-spin-button {
    -webkit-appearance: none;
    margin: 0;
}

.temp-input[type=number] {
    -moz-appearance: textfield;
    appearance: textfield;
}

/* Action Buttons */
.action-buttons {
    display: flex;
    gap: 1rem;
    flex-wrap: wrap;
    justify-content: center;
}

.btn {
    display: inline-flex;
    align-items: center;
    gap: 0.5rem;
    padding: 0.875rem 1.5rem;
    font-size: 1rem;
    font-weight: 600;
    border: none;
    border-radius: 12px;
    cursor: pointer;
    transition: all 0.3s ease;
    min-height: 44px;
    font-family: inherit;
}

.btn-clear {
    background: linear-gradient(135deg, var(--color-hot), var(--color-warm));
    color: white;
    box-shadow: 0 4px 12px rgba(239, 68, 68, 0.3);
}

.btn-clear:hover {
    transform: translateY(-2px);
    box-shadow: 0 6px 16px rgba(239, 68, 68, 0.4);
}

.btn-theme {
    background: linear-gradient(135deg, var(--color-cool), var(--color-moderate));
    color: white;
    box-shadow: 0 4px 12px rgba(6, 182, 212, 0.3);
}

.btn-theme:hover {
    transform: translateY(-2px);
    box-shadow: 0 6px 16px rgba(6, 182, 212, 0.4);
}

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

.btn-return {
    display: inline-flex;
    align-items: center;
    gap: 0.5rem;
    padding: 0.75rem 1.25rem;
    background: var(--bg-secondary);
    color: var(--text-primary);
    border: 1px solid var(--border);
    border-radius: 12px;
    text-decoration: none;
    font-weight: 600;
    margin-bottom: 2rem;
    transition: all 0.3s ease;
    box-shadow: 0 2px 8px var(--shadow);
}

.btn-return:hover {
    transform: translateY(-2px);
    box-shadow: 0 4px 12px var(--shadow-lg);
    border-color: var(--color-cool);
    color: var(--color-cool);
}

/* Info Section */
.info-section {
    margin-bottom: 2rem;
    animation: fadeInUp 0.8s ease;
}

.info-title {
    font-size: clamp(1.5rem, 3vw, 2rem);
    margin-bottom: 1.5rem;
    text-align: center;
    color: var(--text-primary);
}

.reference-grid {
    display: grid;
    grid-template-columns: repeat(auto-fit, minmax(200px, 1fr));
    gap: 1rem;
}

.reference-card {
    background: var(--bg-secondary);
    border-radius: 12px;
    padding: 1.25rem;
    text-align: center;
    border: 1px solid var(--border);
    transition: all 0.3s ease;
}

.reference-card:hover {
    transform: translateY(-2px);
    box-shadow: 0 4px 12px var(--shadow);
}

.reference-card h3 {
    font-size: 1rem;
    margin-bottom: 0.5rem;
    color: var(--text-primary);
}

.reference-card p {
    font-size: 0.875rem;
    color: var(--text-secondary);
    font-weight: 500;
}

/* Footer */
.footer {
    text-align: center;
    padding: 2rem 0;
    color: var(--text-secondary);
    font-size: 0.875rem;
}

/* Animations */
@keyframes fadeInDown {
    from {
        opacity: 0;
        transform: translateY(-20px);
    }

    to {
        opacity: 1;
        transform: translateY(0);
    }
}

@keyframes fadeInUp {
    from {
        opacity: 0;
        transform: translateY(20px);
    }

    to {
        opacity: 1;
        transform: translateY(0);
    }
}

/* Responsive Design */
@media (max-width: 768px) {
    .converter-grid {
        grid-template-columns: 1fr;
    }

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

    .action-buttons {
        flex-direction: column;
    }

    .btn {
        width: 100%;
        justify-content: center;
    }
}

@media (max-width: 480px) {
    .reference-grid {
        grid-template-columns: 1fr;
    }
}

/* Accessibility */
@media (prefers-reduced-motion: reduce) {

    *,
    *::before,
    *::after {
        animation-duration: 0.01ms !important;
        animation-iteration-count: 1 !important;
        transition-duration: 0.01ms !important;
    }
}

/* Focus Visible for Keyboard Navigation */
.btn:focus-visible,
.temp-input:focus-visible {
    outline: 3px solid var(--color-moderate);
    outline-offset: 2px;
}

/* High Contrast Mode Support */
@media (prefers-contrast: high) {

    .converter-card,
    .reference-card {
        border-width: 2px;
    }
}

/* SEO Content Section */
.seo-content {
    background: var(--bg-secondary);
    border-radius: 24px;
    padding: clamp(1.5rem, 4vw, 3rem);
    margin-bottom: 3rem;
    box-shadow: 0 10px 40px var(--shadow-lg);
    border: 1px solid var(--border);
    animation: fadeInUp 0.8s ease;
}

.seo-content h2 {
    font-size: clamp(1.5rem, 3vw, 2.25rem);
    margin: 2.5rem 0 1.5rem;
    color: var(--text-primary);
    border-bottom: 2px solid var(--border);
    padding-bottom: 0.5rem;
}

.seo-content h2:first-child {
    margin-top: 0;
}

.seo-content h3 {
    font-size: 1.25rem;
    margin: 2rem 0 1rem;
    color: var(--text-primary);
    font-weight: 700;
}

.seo-content p {
    margin-bottom: 1.5rem;
    color: var(--text-secondary);
    font-size: 1rem;
    line-height: 1.8;
}

.seo-content ul,
.seo-content ol {
    margin-bottom: 1.5rem;
    padding-left: 1.5rem;
    color: var(--text-secondary);
}

.seo-content li {
    margin-bottom: 0.5rem;
    line-height: 1.6;
}

.seo-content strong {
    color: var(--text-primary);
}

/* Tables */
.seo-content table {
    width: 100%;
    border-collapse: collapse;
    margin: 2rem 0;
    background: var(--bg-primary);
    border-radius: 12px;
    overflow: hidden;
    box-shadow: 0 4px 12px var(--shadow);
}

.seo-content th,
.seo-content td {
    padding: 1rem;
    text-align: left;
    border-bottom: 1px solid var(--border);
    color: var(--text-secondary);
}

.seo-content th {
    background: var(--bg-secondary);
    color: var(--text-primary);
    font-weight: 700;
}

.seo-content tr:last-child td {
    border-bottom: none;
}

.seo-content tr:hover td {
    background: rgba(0, 0, 0, 0.02);
    color: var(--text-primary);
}

/* Responsiveness for tables */
@media (max-width: 640px) {
    .seo-content table {
        display: block;
        overflow-x: auto;
        white-space: nowrap;
    }
}