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

:root {
    --bg-primary: #f8f9fa;
    --bg-secondary: #ffffff;
    --text-primary: #333333;
    --text-secondary: #666666;
    --accent-color: #667eea;
    --accent-gradient: linear-gradient(135deg, #667eea 0%, #764ba2 100%);
    --border-color: #e0e0e0;
    --shadow-color: rgba(0,0,0,0.1);
}

body.dark-mode {
    --bg-primary: #1a1a2e;
    --bg-secondary: #16213e;
    --text-primary: #e4e4e4;
    --text-secondary: #a0a0a0;
    --accent-color: #a78bfa;
    --accent-gradient: linear-gradient(135deg, #667eea 0%, #764ba2 100%);
    --border-color: #2d3748;
    --shadow-color: rgba(0,0,0,0.3);
}

body {
    font-family: -apple-system, BlinkMacSystemFont, 'Segoe UI', Roboto, Oxygen, Ubuntu, sans-serif;
    background-color: var(--bg-primary);
    color: var(--text-primary);
    line-height: 1.6;
    transition: all 0.3s ease;
}

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

header {
    text-align: center;
    margin-bottom: 30px;
    padding: 20px;
    background: var(--accent-gradient);
    color: white;
    border-radius: 10px;
    box-shadow: 0 4px 15px var(--shadow-color);
    position: relative;
}

.header-controls {
    position: absolute;
    top: 15px;
    right: 15px;
}

.theme-btn {
    background: rgba(255,255,255,0.2);
    border: none;
    border-radius: 50%;
    width: 40px;
    height: 40px;
    font-size: 18px;
    cursor: pointer;
    transition: all 0.3s;
}

.theme-btn:hover {
    background: rgba(255,255,255,0.3);
    transform: scale(1.1);
}

header h1 {
    font-size: 2rem;
    margin-bottom: 10px;
}

header p {
    opacity: 0.9;
    font-size: 1.1rem;
}

.controls {
    background: var(--bg-secondary);
    padding: 25px;
    border-radius: 10px;
    box-shadow: 0 2px 10px var(--shadow-color);
    margin-bottom: 20px;
}

.input-group {
    display: flex;
    gap: 10px;
    margin-bottom: 20px;
    flex-wrap: wrap;
}

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

.smiles-input-wrapper {
    flex: 1;
    min-width: 300px;
    position: relative;
}

.input-group input {
    width: 100%;
    padding: 12px 15px;
    border: 2px solid var(--border-color);
    border-radius: 6px;
    font-size: 16px;
    background: var(--bg-secondary);
    color: var(--text-primary);
    transition: border-color 0.3s;
}

.input-group input:focus {
    outline: none;
    border-color: var(--accent-color);
}

.smiles-validation {
    position: absolute;
    right: 10px;
    top: 50%;
    transform: translateY(-50%);
    font-size: 18px;
}

.input-group button {
    padding: 12px 25px;
    background: var(--accent-gradient);
    color: white;
    border: none;
    border-radius: 6px;
    font-size: 16px;
    cursor: pointer;
    transition: transform 0.2s, box-shadow 0.2s;
}

.input-group button:hover {
    transform: translateY(-2px);
    box-shadow: 0 4px 12px rgba(102, 126, 234, 0.4);
}

.input-group button:disabled {
    opacity: 0.6;
    cursor: not-allowed;
    transform: none;
}

.pubchem-search {
    margin-bottom: 20px;
}

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

.pubchem-controls {
    display: flex;
    gap: 10px;
    flex-wrap: wrap;
}

.pubchem-controls input {
    flex: 1;
    min-width: 200px;
    padding: 10px 15px;
    border: 2px solid var(--border-color);
    border-radius: 6px;
    font-size: 14px;
    background: var(--bg-secondary);
    color: var(--text-primary);
}

.pubchem-controls input:focus {
    outline: none;
    border-color: var(--accent-color);
}

.pubchem-results {
    margin-top: 10px;
    max-height: 150px;
    overflow-y: auto;
}

.pubchem-result-item {
    padding: 8px 12px;
    background: var(--bg-primary);
    border-radius: 6px;
    margin-bottom: 5px;
    cursor: pointer;
    transition: all 0.2s;
}

.pubchem-result-item:hover {
    background: var(--accent-color);
    color: white;
}

.file-upload-section {
    display: flex;
    align-items: center;
    gap: 15px;
    margin-bottom: 20px;
    flex-wrap: wrap;
}

.file-upload-label {
    display: flex;
    align-items: center;
    gap: 8px;
    padding: 10px 20px;
    background: var(--bg-primary);
    border: 2px dashed var(--accent-color);
    border-radius: 8px;
    cursor: pointer;
    font-size: 14px;
    color: var(--accent-color);
    transition: all 0.2s;
}

.file-upload-label:hover {
    background: rgba(102, 126, 234, 0.1);
    border-color: #764ba2;
}

.file-name {
    font-size: 14px;
    color: var(--text-secondary);
    max-width: 300px;
    overflow: hidden;
    text-overflow: ellipsis;
    white-space: nowrap;
}

.style-group {
    display: flex;
    align-items: center;
    gap: 15px;
    margin-bottom: 20px;
    flex-wrap: wrap;
}

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

.style-group select {
    padding: 10px 15px;
    border: 2px solid var(--border-color);
    border-radius: 6px;
    font-size: 15px;
    background: var(--bg-secondary);
    color: var(--text-primary);
    cursor: pointer;
    min-width: 150px;
}

.style-group select:focus {
    outline: none;
    border-color: var(--accent-color);
}

.label-controls {
    display: flex;
    align-items: center;
    gap: 20px;
    margin-bottom: 20px;
    flex-wrap: wrap;
}

.checkbox-label {
    display: flex;
    align-items: center;
    gap: 8px;
    cursor: pointer;
    font-size: 15px;
    color: var(--text-primary);
    user-select: none;
}

.checkbox-label input[type="checkbox"] {
    width: 18px;
    height: 18px;
    cursor: pointer;
    accent-color: var(--accent-color);
}

.checkbox-label:hover {
    color: var(--accent-color);
}

.reset-btn {
    padding: 8px 16px;
    background: #6c757d;
    color: white;
    border: none;
    border-radius: 6px;
    font-size: 14px;
    cursor: pointer;
    transition: all 0.2s;
}

.reset-btn:hover {
    background: #5a6268;
    transform: translateY(-1px);
}

.export-buttons {
    display: flex;
    gap: 8px;
}

.export-btn {
    padding: 8px 16px;
    background: var(--accent-color);
    color: white;
    border: none;
    border-radius: 6px;
    font-size: 14px;
    cursor: pointer;
    transition: all 0.2s;
}

.export-btn:hover {
    background: #5a6fd6;
    transform: translateY(-1px);
}

.bg-color-control {
    display: flex;
    align-items: center;
    gap: 8px;
}

.bg-color-control label {
    font-size: 14px;
    color: var(--text-primary);
    font-weight: 600;
}

.bg-color-control select {
    padding: 6px 10px;
    border: 2px solid var(--border-color);
    border-radius: 6px;
    font-size: 14px;
    background: var(--bg-secondary);
    color: var(--text-primary);
    cursor: pointer;
    min-width: 110px;
}

.bg-color-control select:focus {
    outline: none;
    border-color: var(--accent-color);
}

.examples {
    display: flex;
    align-items: center;
    gap: 10px;
    flex-wrap: wrap;
}

.examples span {
    font-weight: 600;
    color: var(--text-secondary);
}

.advanced-features {
    display: grid;
    grid-template-columns: repeat(auto-fit, minmax(280px, 1fr));
    gap: 20px;
    margin-top: 20px;
    padding-top: 20px;
    border-top: 1px solid var(--border-color);
}

.feature-section {
    background: var(--bg-primary);
    padding: 15px;
    border-radius: 8px;
}

.feature-section h4 {
    margin-bottom: 15px;
    color: var(--text-primary);
    font-size: 15px;
}

.measurement-controls {
    display: flex;
    flex-wrap: wrap;
    gap: 8px;
    margin-bottom: 10px;
}

.measurement-controls .feature-btn.active {
    background: #28a745;
}

.measurement-result {
    background: var(--bg-secondary);
    border: 2px solid #28a745;
    border-radius: 8px;
    padding: 12px;
    font-size: 14px;
}

.measurement-result strong {
    color: #28a745;
}

.selection-controls, .shape-controls {
    display: flex;
    flex-wrap: wrap;
    gap: 10px;
    align-items: center;
}

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

.select-group label {
    font-size: 13px;
    color: var(--text-secondary);
    white-space: nowrap;
}

.select-group select {
    padding: 6px 10px;
    border: 2px solid var(--border-color);
    border-radius: 6px;
    font-size: 13px;
    background: var(--bg-secondary);
    color: var(--text-primary);
}

.feature-btn {
    padding: 8px 14px;
    background: var(--accent-color);
    color: white;
    border: none;
    border-radius: 6px;
    font-size: 13px;
    cursor: pointer;
    transition: all 0.2s;
}

.feature-btn:hover {
    background: #5a6fd6;
}

.feature-btn.secondary {
    background: #6c757d;
}

.feature-btn.secondary:hover {
    background: #5a6268;
}

.shape-buttons {
    display: flex;
    flex-wrap: wrap;
    gap: 8px;
}

.shape-color {
    display: flex;
    align-items: center;
    gap: 8px;
    margin-top: 10px;
}

.shape-color label {
    font-size: 13px;
    color: var(--text-secondary);
}

.shape-color input[type="color"] {
    width: 36px;
    height: 28px;
    border: 2px solid var(--border-color);
    border-radius: 4px;
    cursor: pointer;
}

.feature-hint {
    font-size: 13px;
    color: var(--text-secondary);
    margin-bottom: 10px;
    font-style: italic;
}

.atom-info-panel {
    background: var(--bg-secondary);
    border: 2px solid var(--accent-color);
    border-radius: 8px;
    padding: 12px;
    margin-top: 10px;
}

.atom-info-content {
    display: flex;
    align-items: center;
    gap: 15px;
}

.atom-symbol {
    width: 50px;
    height: 50px;
    background: var(--accent-gradient);
    color: white;
    border-radius: 50%;
    display: flex;
    align-items: center;
    justify-content: center;
    font-size: 20px;
    font-weight: bold;
}

.atom-details p {
    margin: 4px 0;
    font-size: 13px;
    color: var(--text-primary);
}

.atom-details strong {
    color: var(--accent-color);
}

.bond-info-panel {
    background: var(--bg-secondary);
    border: 2px solid #28a745;
    border-radius: 8px;
    padding: 12px;
    margin-top: 10px;
}

.bond-info-content {
    display: flex;
    align-items: center;
    gap: 15px;
}

.bond-header {
    display: flex;
    flex-direction: column;
    align-items: center;
    gap: 5px;
    min-width: 70px;
}

.bond-icon {
    font-size: 24px;
}

#bond-type {
    font-size: 14px;
    font-weight: bold;
    color: #28a745;
}

.bond-details p {
    margin: 4px 0;
    font-size: 13px;
    color: var(--text-primary);
}

.bond-details strong {
    color: #28a745;
}

.history-list {
    max-height: 150px;
    overflow-y: auto;
}

.history-item {
    padding: 8px 12px;
    background: var(--bg-secondary);
    border-radius: 6px;
    margin-bottom: 5px;
    cursor: pointer;
    transition: all 0.2s;
    font-size: 13px;
}

.history-item:hover {
    background: var(--accent-color);
    color: white;
}

.history-item .history-smiles {
    font-size: 11px;
    color: var(--text-secondary);
    margin-top: 3px;
}

.history-item:hover .history-smiles {
    color: rgba(255,255,255,0.8);
}

.empty-history {
    color: var(--text-secondary);
    font-style: italic;
    font-size: 13px;
}

#status-message {
    margin-top: 15px;
    padding: 10px 15px;
    border-radius: 5px;
    font-weight: 500;
    display: none;
}

#status-message.success {
    display: block;
    background: #d4edda;
    color: #155724;
    border: 1px solid #c3e6cb;
}

#status-message.error {
    display: block;
    background: #f8d7da;
    color: #721c24;
    border: 1px solid #f5c6cb;
}

#status-message.info {
    display: block;
    background: #d1ecf1;
    color: #0c5460;
    border: 1px solid #bee5eb;
}

.viewer-section {
    background: var(--bg-secondary);
    border-radius: 10px;
    box-shadow: 0 2px 10px var(--shadow-color);
    overflow: hidden;
    margin-bottom: 20px;
}

#viewer-container {
    width: 100%;
    height: 500px;
    position: relative;
}

.info-section {
    background: var(--bg-secondary);
    padding: 20px;
    border-radius: 10px;
    box-shadow: 0 2px 10px var(--shadow-color);
}

.info-section h3 {
    color: var(--text-primary);
    margin-bottom: 15px;
    padding-bottom: 10px;
    border-bottom: 2px solid var(--accent-color);
}

#molecule-info p {
    margin-bottom: 8px;
    color: var(--text-primary);
}

#molecule-info strong {
    color: var(--accent-color);
}

@media (max-width: 768px) {
    .container {
        padding: 10px;
    }

    header h1 {
        font-size: 1.5rem;
    }

    .header-controls {
        position: static;
        margin-top: 10px;
    }

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

    .input-group input {
        min-width: 100%;
    }

    .input-group button {
        width: 100%;
    }

    #viewer-container {
        height: 400px;
    }
}

/* Keyboard Shortcuts Modal */
.shortcuts-modal {
    position: fixed;
    top: 0;
    left: 0;
    width: 100%;
    height: 100%;
    background: rgba(0, 0, 0, 0.5);
    display: flex;
    align-items: center;
    justify-content: center;
    z-index: 1000;
}

.shortcuts-content {
    background: var(--bg-secondary);
    border-radius: 12px;
    padding: 25px;
    max-width: 400px;
    width: 90%;
    box-shadow: 0 10px 40px rgba(0, 0, 0, 0.3);
}

.shortcuts-header {
    display: flex;
    justify-content: space-between;
    align-items: center;
    margin-bottom: 20px;
    padding-bottom: 15px;
    border-bottom: 2px solid var(--border-color);
}

.shortcuts-header h3 {
    color: var(--text-primary);
    margin: 0;
}

.close-btn {
    background: none;
    border: none;
    font-size: 28px;
    cursor: pointer;
    color: var(--text-secondary);
    line-height: 1;
}

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

.shortcuts-list {
    display: flex;
    flex-direction: column;
    gap: 12px;
}

.shortcut-item {
    display: flex;
    align-items: center;
    gap: 12px;
    font-size: 14px;
    color: var(--text-primary);
}

.shortcut-item kbd {
    background: var(--bg-primary);
    border: 1px solid var(--border-color);
    border-radius: 4px;
    padding: 4px 8px;
    font-family: monospace;
    font-size: 12px;
    min-width: 28px;
    text-align: center;
}

/* Atom Tooltip */
.atom-tooltip {
    position: absolute;
    background: rgba(0, 0, 0, 0.85);
    color: white;
    padding: 8px 12px;
    border-radius: 6px;
    font-size: 12px;
    pointer-events: none;
    z-index: 100;
    white-space: nowrap;
    box-shadow: 0 2px 10px rgba(0, 0, 0, 0.3);
}

.atom-tooltip .tooltip-element {
    font-size: 16px;
    font-weight: bold;
    margin-bottom: 4px;
}

.atom-tooltip .tooltip-info {
    opacity: 0.8;
}

/* Preset Controls */
.preset-controls {
    display: flex;
    align-items: center;
    gap: 8px;
    margin-left: 15px;
}

.preset-controls label {
    font-size: 14px;
    color: var(--text-secondary);
    white-space: nowrap;
}

.preset-controls select {
    padding: 8px 12px;
    border: 2px solid var(--border-color);
    border-radius: 6px;
    font-size: 13px;
    background: var(--bg-secondary);
    color: var(--text-primary);
    cursor: pointer;
}

.preset-controls select:focus {
    outline: none;
    border-color: var(--accent-color);
}

/* Background Color Quick Buttons */
.bg-color-control {
    display: flex;
    align-items: center;
    gap: 6px;
}

.bg-color-control > label {
    font-size: 14px;
    color: var(--text-primary);
    font-weight: 600;
    margin-right: 5px;
}

.bg-color-btn {
    width: 28px;
    height: 28px;
    border: 2px solid var(--border-color);
    border-radius: 4px;
    cursor: pointer;
    transition: all 0.2s;
}

.bg-color-btn:hover {
    transform: scale(1.15);
    border-color: var(--accent-color);
}

.bg-color-btn.active {
    border-color: var(--accent-color);
    box-shadow: 0 0 0 2px var(--accent-color);
}

/* Molecular Properties */
.molecular-properties {
    margin-top: 20px;
    padding-top: 20px;
    border-top: 2px solid var(--border-color);
}

.molecular-properties h4 {
    color: var(--text-primary);
    margin-bottom: 15px;
}

.properties-grid {
    display: grid;
    grid-template-columns: repeat(auto-fit, minmax(140px, 1fr));
    gap: 12px;
    margin-bottom: 15px;
}

.property-item {
    background: var(--bg-primary);
    padding: 12px;
    border-radius: 8px;
    text-align: center;
}

.property-label {
    display: block;
    font-size: 11px;
    color: var(--text-secondary);
    margin-bottom: 5px;
    text-transform: uppercase;
    letter-spacing: 0.5px;
}

.property-value {
    display: block;
    font-size: 16px;
    font-weight: 600;
    color: var(--accent-color);
}

.atom-counts {
    margin-top: 15px;
}

.atom-composition {
    display: flex;
    flex-wrap: wrap;
    gap: 8px;
    margin-top: 8px;
}

.atom-composition .atom-tag {
    display: inline-flex;
    align-items: center;
    gap: 6px;
    background: var(--bg-primary);
    padding: 6px 12px;
    border-radius: 20px;
    font-size: 13px;
}

.atom-composition .atom-dot {
    width: 12px;
    height: 12px;
    border-radius: 50%;
}

.atom-composition .atom-count {
    font-weight: 600;
    color: var(--accent-color);
}

@media (max-width: 768px) {
    .header-controls {
        display: flex;
        gap: 8px;
        justify-content: center;
    }
    
    .preset-controls {
        margin-left: 0;
        margin-top: 10px;
        width: 100%;
    }
    
    .preset-controls select {
        flex: 1;
    }
    
    .bg-color-control {
        flex-wrap: wrap;
    }
    
    .properties-grid {
        grid-template-columns: repeat(2, 1fr);
    }
}