* {
    margin: 0;
    padding: 0;
    box-sizing: border-box;
    font-family: 'Segoe UI', Tahoma, Geneva, Verdana, sans-serif;
}

:root {
    --bg-color: #f5f5f5;
    --container-bg: white;
    --text-color: #333;
    --accent-color: #3498db;
    --accent-hover: #2980b9;
    --danger-color: #e74c3c;
    --danger-hover: #c0392b;
    --section-bg: #f8f9fa;
    --border-color: #ddd;
    --heading-color: #2c3e50;
    --table-header-bg: #f2f2f2;
    --btn-bg: #f8f9fa;
    --btn-hover: #e9ecef;
}

body {
    background-color: var(--bg-color);
    color: var(--text-color);
    line-height: 1.6;
    transition: background-color 0.3s, color 0.3s;
    font-size: 16px;
}

.dark-mode {
    --bg-color: #222;
    --container-bg: #333;
    --text-color: #eee;
    --accent-color: #2980b9;
    --accent-hover: #3498db;
    --section-bg: #444;
    --border-color: #555;
    --heading-color: #ccc;
    --table-header-bg: #555;
    --btn-bg: #444;
    --btn-hover: #555;
}

.container {
    max-width: 800px;
    margin: 40px auto;
    padding: 20px;
    background-color: var(--container-bg);
    border-radius: 10px;
    box-shadow: 0 2px 10px rgba(0, 0, 0, 0.1);
    transition: background-color 0.3s;
}

header {
    text-align: center;
    margin-bottom: 20px;
}

h1 {
    color: var(--heading-color);
    margin-bottom: 5px;
    font-size: 2rem;
}

.tagline {
    color: var(--text-color);
    font-size: 1rem;
    opacity: 0.8;
}

h2 {
    margin-bottom: 15px;
    color: var(--heading-color);
    font-size: 1.5rem;
}

h3 {
    color: var(--heading-color);
    font-size: 1.2rem;
    margin: 15px 0 10px;
}

.sr-only {
    position: absolute;
    width: 1px;
    height: 1px;
    padding: 0;
    margin: -1px;
    overflow: hidden;
    clip: rect(0, 0, 0, 0);
    white-space: nowrap;
    border-width: 0;
}

.unit-type-selector {
    display: flex;
    justify-content: center;
    margin-bottom: 25px;
    flex-wrap: wrap;
}

.unit-type-btn {
    padding: 10px 15px;
    margin: 0 5px 10px;
    background-color: var(--btn-bg);
    border: 1px solid var(--border-color);
    border-radius: 5px;
    cursor: pointer;
    transition: all 0.3s;
    font-size: 1rem;
    color: var(--text-color);
}

.unit-type-btn:hover {
    background-color: var(--btn-hover);
}

.unit-type-btn.active {
    background-color: var(--accent-color);
    color: white;
    border-color: var(--accent-color);
}

.converter {
    display: flex;
    align-items: center;
    justify-content: space-between;
    margin-bottom: 20px;
    flex-wrap: wrap;
}

.input-group {
    display: flex;
    flex-direction: column;
    width: 45%;
}

label {
    margin-bottom: 5px;
    font-weight: 600;
    color: var(--heading-color);
}

input, select {
    padding: 12px;
    margin-bottom: 10px;
    border: 1px solid var(--border-color);
    border-radius: 5px;
    font-size: 1rem;
    background-color: var(--container-bg);
    color: var(--text-color);
}

input:focus, select:focus {
    outline: none;
    border-color: var(--accent-color);
    box-shadow: 0 0 0 2px rgba(52, 152, 219, 0.3);
}

.swap-btn {
    background-color: var(--accent-color);
    color: white;
    width: 40px;
    height: 40px;
    border-radius: 50%;
    display: flex;
    align-items: center;
    justify-content: center;
    font-size: 1.2rem;
    cursor: pointer;
    transition: background-color 0.3s, transform 0.2s;
    border: none;
}

.swap-btn:hover {
    background-color: var(--accent-hover);
    transform: scale(1.1);
}

.swap-btn:focus {
    outline: none;
    box-shadow: 0 0 0 3px rgba(52, 152, 219, 0.5);
}

.action-buttons {
    display: flex;
    justify-content: center;
    margin-bottom: 20px;
    gap: 10px;
}

.action-buttons button {
    padding: 8px 15px;
    background-color: var(--btn-bg);
    border: 1px solid var(--border-color);
    border-radius: 5px;
    cursor: pointer;
    transition: all 0.3s;
    display: flex;
    align-items: center;
    gap: 5px;
    color: var(--text-color);
    font-size: 0.9rem;
}

.action-buttons button:hover {
    background-color: var(--btn-hover);
    transform: translateY(-2px);
}

.action-buttons button:focus {
    outline: none;
    box-shadow: 0 0 0 2px rgba(52, 152, 219, 0.3);
}

.action-buttons i {
    font-size: 0.9rem;
}

.formula-display {
    background-color: var(--section-bg);
    padding: 10px 15px;
    border-radius: 5px;
    margin-bottom: 20px;
    font-family: monospace;
    font-size: 0.9rem;
    color: var(--text-color);
    min-height: 40px;
    display: flex;
    align-items: center;
    border-left: 4px solid var(--accent-color);
}

.section-header {
    display: flex;
    justify-content: space-between;
    align-items: center;
    margin-bottom: 15px;
}

.history-section, .table-section {
    margin-bottom: 30px;
    background-color: var(--section-bg);
    padding: 15px;
    border-radius: 5px;
    box-shadow: 0 1px 3px rgba(0, 0, 0, 0.1);
}

.history-controls, .table-controls {
    display: flex;
    gap: 10px;
}

#clearHistoryBtn {
    background-color: var(--danger-color);
    color: white;
    border: none;
    padding: 8px 12px;
    border-radius: 4px;
    cursor: pointer;
    font-size: 0.9rem;
    transition: background-color 0.3s;
    display: flex;
    align-items: center;
    gap: 5px;
}

#clearHistoryBtn:hover {
    background-color: var(--danger-hover);
}

#clearHistoryBtn:focus {
    outline: none;
    box-shadow: 0 0 0 2px rgba(231, 76, 60, 0.3);
}

#printTableBtn {
    background-color: var(--btn-bg);
    color: var(--text-color);
    border: 1px solid var(--border-color);
    width: 32px;
    height: 32px;
    border-radius: 4px;
    cursor: pointer;
    transition: background-color 0.3s, transform 0.2s;
    display: flex;
    align-items: center;
    justify-content: center;
}

#printTableBtn:hover {
    background-color: var(--btn-hover);
    transform: scale(1.1);
}

#printTableBtn:focus {
    outline: none;
    box-shadow: 0 0 0 2px rgba(52, 152, 219, 0.3);
}

.history-list {
    list-style-type: none;
    max-height: 200px;
    overflow-y: auto;
}

.history-list li {
    padding: 8px 10px;
    border-bottom: 1px solid var(--border-color);
    cursor: pointer;
    transition: background-color 0.2s, transform 0.1s;
    color: var(--text-color);
}

.history-list li:hover {
    background-color: var(--btn-hover);
    transform: translateX(3px);
}

.history-list li:focus {
    outline: none;
    box-shadow: inset 0 0 0 2px var(--accent-color);
}

.history-list li:last-child {
    border-bottom: none;
}

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

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

th {
    background-color: var(--table-header-bg);
    font-weight: 600;
}

.theme-toggle {
    display: flex;
    align-items: center;
    justify-content: flex-end;
    margin-bottom: 20px;
    gap: 10px;
    color: var(--text-color);
}

.switch-container {
    position: relative;
    display: inline-block;
    width: 50px;
    height: 24px;
}

.switch-container input {
    opacity: 0;
    width: 0;
    height: 0;
}

.slider {
    position: absolute;
    cursor: pointer;
    top: 0;
    left: 0;
    right: 0;
    bottom: 0;
    background-color: #ccc;
    transition: .4s;
}

.slider:before {
    position: absolute;
    content: "";
    height: 16px;
    width: 16px;
    left: 4px;
    bottom: 4px;
    background-color: white;
    transition: .4s;
}

input:checked + .slider {
    background-color: var(--accent-color);
}

input:focus + .slider {
    box-shadow: 0 0 1px var(--accent-color);
}

input:checked + .slider:before {
    transform: translateX(26px);
}

.slider.round {
    border-radius: 24px;
}

.slider.round:before {
    border-radius: 50%;
}

.notification {
    position: fixed;
    bottom: 20px;
    right: 20px;
    background-color: var(--accent-color);
    color: white;
    padding: 10px 20px;
    border-radius: 5px;
    box-shadow: 0 2px 10px rgba(0, 0, 0, 0.2);
    transform: translateY(100px);
    opacity: 0;
    transition: transform 0.3s, opacity 0.3s;
    z-index: 100;
    font-size: 0.9rem;
}

.notification.show {
    transform: translateY(0);
    opacity: 1;
}

footer {
    text-align: center;
    margin-top: 30px;
    color: var(--text-color);
    font-size: 0.9rem;
    border-top: 1px solid var(--border-color);
    padding-top: 20px;
}

footer a {
    color: var(--accent-color);
    text-decoration: none;
}

footer a:hover {
    text-decoration: underline;
}

kbd {
    background-color: var(--section-bg);
    border: 1px solid var(--border-color);
    border-radius: 3px;
    box-shadow: 0 1px 1px rgba(0,0,0,.2);
    color: var(--text-color);
    display: inline-block;
    font-size: 0.8rem;
    font-family: monospace;
    line-height: 1;
    padding: 2px 4px;
}

.modal {
    display: none;
    position: fixed;
    z-index: 1000;
    left: 0;
    top: 0;
    width: 100%;
    height: 100%;
    overflow: auto;
    background-color: rgba(0,0,0,0.5);
    backdrop-filter: blur(3px);
}

.modal-content {
    background-color: var(--container-bg);
    margin: 10% auto;
    padding: 20px;
    border-radius: 10px;
    box-shadow: 0 5px 20px rgba(0,0,0,0.3);
    max-width: 600px;
    color: var(--text-color);
    position: relative;
}

.close-btn {
    color: var(--text-color);
    float: right;
    font-size: 28px;
    font-weight: bold;
    cursor: pointer;
    transition: color 0.2s;
}

.close-btn:hover {
    color: var(--accent-color);
}

.help-content {
    margin-top: 20px;
}

.help-content ul, .help-content ol {
    margin-left: 25px;
}

.help-content li {
    margin-bottom: 5px;
}

/* SEO Content Styling */
.seo-content {
    margin-top: 30px;
    padding-top: 20px;
    border-top: 1px solid var(--border-color);
    color: var(--text-color);
}

.seo-section {
    margin-bottom: 30px;
}

.seo-subsection {
    margin-bottom: 20px;
}

.seo-content ul {
    margin-left: 25px;
}

.seo-content li {
    margin-bottom: 8px;
}

/* Add AMP compatibility */
.amp-content {
    width: 100%;
    max-width: 100%;
}

/* Responsive styles */
@media (max-width: 768px) {
    .container {
        margin: 20px auto;
        padding: 15px;
    }
    
    h1 {
        font-size: 1.8rem;
    }
    
    .unit-type-btn {
        padding: 8px 12px;
        font-size: 0.9rem;
    }
}

@media (max-width: 600px) {
    .container {
        margin: 10px;
    }
    
    h1 {
        font-size: 1.6rem;
    }
    
    .converter {
        flex-direction: column;
        align-items: stretch;
    }
    
    .input-group {
        width: 100%;
        margin-bottom: 20px;
    }
    
    .swap-btn {
        margin: 10px auto;
        transform: rotate(90deg);
    }
    
    .swap-btn:hover {
        transform: rotate(90deg) scale(1.1);
    }
    
    .action-buttons {
        flex-wrap: wrap;
    }
    
    .action-buttons button {
        flex: 1;
        min-width: 120px;
    }
    
    .modal-content {
        margin: 20% auto;
        width: 90%;
    }
}

@media (prefers-reduced-motion: reduce) {
    * {
        transition: none !important;
        animation: none !important;
    }
}