/* CSS Variables for Light/Dark Theme */
:root {
    --bg-primary: #ffffff;
    --bg-secondary: #f5f5dc;
    --bg-card: #f5f5dc;
    --text-primary: #333333;
    --text-secondary: #666666;
    --border-color: #dddddd;
    --button-primary: #7c3aed;
    --button-primary-hover: #6d28d9;
    --button-secondary: #e5e7eb;
    --button-secondary-hover: #d1d5db;
    --badge-hex: #8b5cf6;
    --badge-decimal: #10b981;
    --badge-binary: #f59e0b;
    --input-bg: #ffffff;
    --table-header-bg: #e5e7eb;
    --table-row-even: #f9fafb;
    --shadow: rgba(0, 0, 0, 0.1);
}

[data-theme="dark"] {
    --bg-primary: #1a1a1a;
    --bg-secondary: #2d2d2d;
    --bg-card: #2d2d2d;
    --text-primary: #e0e0e0;
    --text-secondary: #b0b0b0;
    --border-color: #444444;
    --button-primary: #8b5cf6;
    --button-primary-hover: #a78bfa;
    --button-secondary: #374151;
    --button-secondary-hover: #4b5563;
    --badge-hex: #8b5cf6;
    --badge-decimal: #10b981;
    --badge-binary: #f59e0b;
    --input-bg: #374151;
    --table-header-bg: #374151;
    --table-row-even: #2d2d2d;
    --shadow: rgba(0, 0, 0, 0.3);
}

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

body {
    font-family: 'Segoe UI', Tahoma, Geneva, Verdana, sans-serif;
    background-color: var(--bg-primary);
    color: var(--text-primary);
    line-height: 1.6;
    transition: background-color 0.3s ease, color 0.3s ease;
}

.container {
    max-width: 1200px;
    margin: 0 auto;
    padding: 20px;
}

/* Theme Toggle Button */
.theme-toggle {
    position: fixed;
    top: 20px;
    right: 20px;
    width: 60px;
    height: 60px;
    border-radius: 50%;
    background: var(--button-primary);
    border: none;
    cursor: pointer;
    display: flex;
    align-items: center;
    justify-content: center;
    font-size: 28px;
    box-shadow: 0 4px 12px var(--shadow);
    transition: all 0.3s ease;
    z-index: 1000;
}

.theme-toggle:hover {
    transform: scale(1.1);
}

/* Header */
.header {
    text-align: center;
    margin-bottom: 30px;
}

.header h1 {
    font-size: 2.5rem;
    background: linear-gradient(135deg, #667eea 0%, #764ba2 100%);
    -webkit-background-clip: text;
    -webkit-text-fill-color: transparent;
    background-clip: text;
    margin-bottom: 10px;
}

/* Converter Card */
.converter-card {
    background: var(--bg-card);
    border-radius: 12px;
    padding: 30px;
    box-shadow: 0 4px 20px var(--shadow);
    margin-bottom: 30px;
}

/* Converter Header with Swap Button */
.converter-header {
    display: flex;
    align-items: center;
    justify-content: space-between;
    gap: 20px;
    margin-bottom: 25px;
    flex-wrap: wrap;
}

.base-selector {
    display: flex;
    flex-direction: column;
    gap: 8px;
    flex: 1;
    min-width: 150px;
}

.base-selector label {
    font-weight: 600;
    color: var(--text-primary);
    font-size: 0.95rem;
}

.base-dropdown {
    padding: 12px 16px;
    border: 2px solid var(--border-color);
    border-radius: 8px;
    font-size: 1rem;
    background: var(--input-bg);
    color: var(--text-primary);
    cursor: pointer;
    transition: all 0.3s ease;
}

.base-dropdown:hover {
    border-color: var(--button-primary);
}

.base-dropdown:focus {
    outline: none;
    border-color: var(--button-primary);
    box-shadow: 0 0 0 3px rgba(124, 58, 237, 0.1);
}

/* SWAP BUTTON - Styled for horizontal arrow ⇄ */
.swap-btn {
    padding: 12px 20px;
    background: linear-gradient(135deg, #667eea 0%, #764ba2 100%);
    color: white;
    border: none;
    border-radius: 8px;
    cursor: pointer;
    font-size: 1.5rem;
    transition: all 0.3s ease;
    display: flex;
    align-items: center;
    justify-content: center;
    min-width: 60px;
    height: 48px;
    box-shadow: 0 2px 8px var(--shadow);
}

.swap-btn:hover {
    transform: scale(1.05);
    box-shadow: 0 4px 12px var(--shadow);
}

.swap-btn:active {
    transform: scale(0.95);
}

.swap-icon {
    display: inline-block;
    transition: transform 0.3s ease;
}

.swap-btn:hover .swap-icon {
    transform: scale(1.2);
}

/* Input Section */
.input-section {
    margin-bottom: 20px;
}

.input-section label {
    display: block;
    margin-bottom: 8px;
    font-weight: 600;
    color: var(--text-primary);
}

.input-with-badge {
    display: flex;
    align-items: center;
    gap: 12px;
    position: relative;
}

.input-with-badge input,
.input-with-badge textarea {
    flex: 1;
    padding: 12px 16px;
    border: 2px solid var(--border-color);
    border-radius: 8px;
    font-size: 1rem;
    background: var(--input-bg);
    color: var(--text-primary);
    transition: all 0.3s ease;
}

.input-with-badge input:focus,
.input-with-badge textarea:focus {
    outline: none;
    border-color: var(--button-primary);
    box-shadow: 0 0 0 3px rgba(124, 58, 237, 0.1);
}

.base-badge {
    padding: 6px 12px;
    border-radius: 6px;
    font-size: 0.85rem;
    font-weight: 700;
    color: white;
    background: var(--badge-hex);
    white-space: nowrap;
}

.badge-decimal {
    background: var(--badge-decimal);
}

.badge-binary {
    background: var(--badge-binary);
}

/* Button Group */
.button-group {
    display: flex;
    gap: 12px;
    margin-bottom: 25px;
    flex-wrap: wrap;
}

.btn {
    padding: 12px 24px;
    border: none;
    border-radius: 8px;
    font-size: 1rem;
    font-weight: 600;
    cursor: pointer;
    transition: all 0.3s ease;
}

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

.btn-primary:hover {
    background: var(--button-primary-hover);
    transform: translateY(-2px);
    box-shadow: 0 4px 12px var(--shadow);
}

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

.btn-secondary:hover {
    background: var(--button-secondary-hover);
}

/* Output Section */
.output-section {
    display: flex;
    flex-direction: column;
    gap: 20px;
}

.output-group {
    display: flex;
    flex-direction: column;
    gap: 8px;
}

.output-group label {
    font-weight: 600;
    color: var(--text-primary);
}

.output-with-actions {
    display: flex;
    align-items: center;
    gap: 12px;
}

.copy-btn {
    padding: 10px 16px;
    background: var(--button-secondary);
    border: 2px solid var(--border-color);
    border-radius: 8px;
    cursor: pointer;
    font-size: 1.2rem;
    transition: all 0.3s ease;
    flex-shrink: 0;
}

.copy-btn:hover {
    background: var(--button-primary);
    border-color: var(--button-primary);
    transform: scale(1.1);
}

.copy-btn.copied {
    background: #10b981;
    border-color: #10b981;
}

.checkbox-group {
    display: flex;
    align-items: center;
    gap: 8px;
}

.checkbox-group input[type="checkbox"] {
    width: 18px;
    height: 18px;
    cursor: pointer;
}

.checkbox-group label {
    cursor: pointer;
    font-weight: 500;
    color: var(--text-primary);
}

textarea {
    min-height: 80px;
    resize: vertical;
    font-family: 'Courier New', monospace;
}

/* Visual Diagram Section */
.diagram-section {
    background: var(--bg-card);
    border-radius: 12px;
    padding: 30px;
    box-shadow: 0 4px 20px var(--shadow);
    margin-bottom: 30px;
}

.diagram-section h2 {
    margin-bottom: 20px;
    color: var(--text-primary);
    font-size: 1.8rem;
}

.visual-diagram {
    background: var(--bg-secondary);
    border-radius: 12px;
    padding: 30px;
    min-height: 300px;
    display: flex;
    flex-direction: column;
    gap: 20px;
    overflow-x: auto;
}

.diagram-row {
    display: flex;
    align-items: center;
    gap: 15px;
    flex-wrap: wrap;
    animation: fadeIn 0.5s ease;
}

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

.digit-card {
    background: linear-gradient(135deg, #667eea 0%, #764ba2 100%);
    color: white;
    padding: 20px;
    border-radius: 10px;
    font-size: 1.5rem;
    font-weight: bold;
    min-width: 80px;
    text-align: center;
    box-shadow: 0 4px 12px rgba(102, 126, 234, 0.3);
}

.calculation-text {
    font-size: 1.2rem;
    color: var(--text-primary);
    font-weight: 500;
}

.result-box {
    background: linear-gradient(135deg, #10b981 0%, #059669 100%);
    color: white;
    padding: 20px 30px;
    border-radius: 10px;
    font-size: 1.5rem;
    font-weight: bold;
    box-shadow: 0 4px 12px rgba(16, 185, 129, 0.3);
}

/* Content Section */
.content-section {
    background: var(--bg-card);
    border-radius: 12px;
    padding: 30px;
    box-shadow: 0 4px 20px var(--shadow);
    margin-bottom: 30px;
}

.content-section h2,
.content-section h3,
.content-section h4 {
    color: var(--text-primary);
    margin-top: 20px;
    margin-bottom: 15px;
}

.content-section p {
    color: var(--text-secondary);
    margin-bottom: 15px;
    line-height: 1.8;
}

/* Table Section */
.table-section {
    background: var(--bg-card);
    border-radius: 12px;
    padding: 30px;
    box-shadow: 0 4px 20px var(--shadow);
    margin-bottom: 30px;
}

.table-section h2 {
    margin-bottom: 20px;
    color: var(--text-primary);
}

.table-wrapper {
    overflow-x: auto;
}

.conversion-table {
    width: 100%;
    border-collapse: collapse;
}

.conversion-table thead {
    background: var(--table-header-bg);
}

.conversion-table th,
.conversion-table td {
    padding: 12px 16px;
    text-align: left;
    border-bottom: 1px solid var(--border-color);
    color: var(--text-primary);
}

.conversion-table tr:nth-child(even) {
    background: var(--table-row-even);
}

.conversion-table tr:hover {
    background: var(--button-secondary);
}

/* See Also Section */
.see-also-section {
    background: var(--bg-card);
    border-radius: 12px;
    padding: 30px;
    box-shadow: 0 4px 20px var(--shadow);
    margin-bottom: 30px;
}

.see-also-section h2 {
    margin-bottom: 20px;
    color: var(--text-primary);
    font-size: 1.8rem;
}

.see-also-grid {
    display: grid;
    grid-template-columns: repeat(auto-fit, minmax(300px, 1fr));
    gap: 20px;
}

.see-also-card {
    display: flex;
    align-items: center;
    gap: 15px;
    padding: 20px;
    background: var(--bg-secondary);
    border: 2px solid var(--border-color);
    border-radius: 10px;
    text-decoration: none;
    color: var(--text-primary);
    transition: all 0.3s ease;
}

.see-also-card:hover {
    transform: translateY(-5px);
    border-color: var(--button-primary);
    box-shadow: 0 6px 20px var(--shadow);
}

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

.card-text {
    font-weight: 600;
    font-size: 1.1rem;
}

/* Footer */
.footer {
    background: var(--bg-secondary);
    border-top: 2px solid var(--border-color);
    padding: 30px;
    text-align: center;
    border-radius: 12px;
    margin-top: 30px;
}

.footer p {
    color: var(--text-secondary);
    font-size: 0.95rem;
}

/* Responsive Design */
@media (max-width: 768px) {
    .converter-header {
        flex-direction: column;
        align-items: stretch;
    }

    .swap-btn {
        width: 100%;
    }

    .button-group {
        flex-direction: column;
    }

    .btn {
        width: 100%;
    }

    .header h1 {
        font-size: 1.8rem;
    }

    .see-also-grid {
        grid-template-columns: 1fr;
    }

    .output-with-actions {
        flex-direction: column;
        align-items: stretch;
    }

    .copy-btn {
        width: 100%;
    }
}