body {
    font-family: monospace;
    max-width: 900px;
    margin: 20px auto;
    padding: 20px;
    background: white;
}

h1 {
    font-size: 18px;
    font-weight: normal;
}

.subtitle {
    font-size: 12px;
    color: #666;
    margin-bottom: 20px;
}

.text-section {
    margin: 20px 0;
}

.text-area {
    width: 100%;
    min-height: 60px;
    padding: 5px;
    font-family: monospace;
    font-size: 14px;
    border: 1px solid #000;
    resize: vertical;
}

.section-label {
    font-size: 12px;
    margin-bottom: 5px;
}

.proof-container {
    margin: 20px 0;
    padding: 10px;
    border: 1px solid #000;
}

.proof-line {
    display: grid;
    grid-template-columns: 30px 1fr 1fr 50px;
    gap: 10px;
    margin-bottom: 8px;
    align-items: center;
    padding-bottom: 8px;
    border-bottom: 1px solid #ccc;
}

.proof-line:last-child {
    border-bottom: none;
}

.line-number {
    text-align: right;
    font-size: 14px;
}

.proof-input, .reason-input {
    padding: 4px;
    font-family: monospace;
    font-size: 14px;
    border: 1px solid #666;
}

.proof-input:focus, .reason-input:focus {
    outline: 1px solid #000;
}

.line-actions {
    display: flex;
    gap: 5px;
}

.line-btn {
    padding: 2px 6px;
    background: white;
    border: 1px solid #999;
    cursor: pointer;
    font-size: 11px;
    font-family: monospace;
}

.line-btn:hover {
    background: #f0f0f0;
}

.proof-controls {
    margin-top: 10px;
    display: flex;
    gap: 10px;
}

.control-btn {
    padding: 4px 8px;
    background: white;
    border: 1px solid #666;
    cursor: pointer;
    font-family: monospace;
    font-size: 12px;
}

.control-btn:hover {
    background: #f0f0f0;
}

.preview-section {
    margin-top: 20px;
    padding: 10px;
    border: 1px dashed #666;
}

.preview-content {
    font-family: serif;
    font-size: 14px;
    line-height: 1.6;
}

.preview-line {
    display: flex;
    justify-content: space-between;
    padding: 5px 0;
    border-bottom: 1px solid #ddd;
}

.preview-line:last-child {
    border-bottom: none;
}

.preview-expr {
    flex: 1;
}

.preview-reason {
    font-style: italic;
    margin-left: 20px;
}

.preview-text {
    margin: 10px 0;
    white-space: pre-wrap;
}

.button-group {
    margin-top: 20px;
}

.btn {
    padding: 5px 10px;
    margin-right: 10px;
    background: white;
    border: 1px solid #000;
    cursor: pointer;
    font-family: monospace;
    font-size: 14px;
}

.btn:hover {
    background: #f0f0f0;
}

.copy-status {
    color: #666;
    margin-left: 10px;
    display: none;
}

.copy-status.show {
    display: inline;
}

.shortcuts-panel {
    margin-top: 30px;
    padding: 10px;
    border: 1px solid #666;
}

.shortcuts-title {
    font-size: 14px;
    margin-bottom: 10px;
}

.shortcut-grid {
    display: grid;
    grid-template-columns: repeat(4, 1fr);
    gap: 5px;
    font-size: 12px;
}

.shortcut-item {
    display: flex;
    justify-content: space-between;
    padding: 2px;
}

.shortcut-from {
    font-family: monospace;
}

.shortcut-to {
    font-weight: bold;
}

.latex-output {
    background: #f0f0f0;
    padding: 10px;
    font-family: monospace;
    font-size: 12px;
    white-space: pre-wrap;
    margin-top: 20px;
    border: 1px solid #666;
}

.hint {
    font-size: 11px;
    color: #666;
    margin-top: 5px;
}

/* Tab styles */
.tabs {
    display: flex;
    gap: 10px;
    margin-bottom: 20px;
    border-bottom: 1px solid #666;
}

.tab-btn {
    padding: 8px 16px;
    background: white;
    border: 1px solid #666;
    border-bottom: none;
    cursor: pointer;
    font-family: monospace;
    font-size: 14px;
    margin-bottom: -1px;
}

.tab-btn:hover {
    background: #f0f0f0;
}

.tab-btn.active {
    background: white;
    border-bottom: 1px solid white;
    font-weight: bold;
}

.tab-content {
    display: none;
}

.tab-content.active {
    display: block;
}

/* Set Theory specific styles */
.set-proof-area {
    width: 100%;
    min-height: 200px;
    padding: 10px;
    font-family: monospace;
    font-size: 14px;
    border: 1px solid #000;
    resize: vertical;
    white-space: pre-wrap;
    tab-size: 4;
}

.set-equation {
    text-align: center;
    margin: 10px 0;
    font-family: 'Cambria Math', 'Latin Modern Math', serif;
    font-size: 14px;
}

.set-inline {
    font-family: 'Cambria Math', 'Latin Modern Math', serif;
}