:root {
    --primary-color: #3a7bd5;
    --secondary-color: #00d2ff;
    --background-color: #f5f7fa;
    --panel-bg: #ffffff;
    --border-color: #e0e0e0;
    --text-color: #333333;
    --opcode-data: #4caf50;
    --opcode-container: #ff9800;
    --opcode-execution: #f44336;
    --opcode-stack: #9c27b0;
}

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

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

.container {
    max-width: 1400px;
    margin: 0 auto;
    padding: 20px;
}

header {
    text-align: center;
    margin-bottom: 30px;
    padding-bottom: 20px;
    border-bottom: 1px solid var(--border-color);
}

h1 {
    color: var(--primary-color);
    margin-bottom: 10px;
}

.main-content {
    display: grid;
    grid-template-columns: 1fr 2fr 1fr;
    gap: 20px;
}

.opcode-panel, .workspace, .output-panel {
    background-color: var(--panel-bg);
    border-radius: 8px;
    box-shadow: 0 2px 10px rgba(0, 0, 0, 0.1);
    padding: 15px;
}

h2 {
    margin-bottom: 15px;
    color: var(--primary-color);
    font-size: 1.3rem;
}

.categories {
    display: flex;
    gap: 8px;
    margin-bottom: 15px;
    flex-wrap: wrap;
}

.category-btn {
    background: none;
    border: 1px solid var(--border-color);
    padding: 5px 10px;
    border-radius: 4px;
    cursor: pointer;
    font-size: 0.9rem;
    transition: all 0.2s;
}

.category-btn:hover {
    background-color: rgba(58, 123, 213, 0.1);
}

.category-btn.active {
    background-color: var(--primary-color);
    color: white;
    border-color: var(--primary-color);
}

.opcode-list {
    display: grid;
    grid-template-columns: repeat(auto-fill, minmax(80px, 1fr));
    gap: 10px;
    overflow-y: auto;
    padding: 5px;
    /* Add scrollbar styling for better UI */
    scrollbar-width: thin;
    scrollbar-color: var(--primary-color) #f0f0f0;
}

/* Style scrollbars for webkit browsers */
.opcode-list::-webkit-scrollbar {
    width: 8px;
}

.opcode-list::-webkit-scrollbar-track {
    background: #f0f0f0;
    border-radius: 4px;
}

.opcode-list::-webkit-scrollbar-thumb {
    background-color: var(--primary-color);
    border-radius: 4px;
}

.opcode-item {
    display: flex;
    flex-direction: column;
    align-items: center;
    padding: 8px;
    border-radius: 6px;
    cursor: grab;
    transition: transform 0.1s, box-shadow 0.1s;
    user-select: none;
    color: white;
    font-weight: 500;
    text-align: center;
    min-height: 70px;
    justify-content: center;
    width: 100%;
    box-sizing: border-box;
}

.opcode-item:hover {
    transform: translateY(-2px);
    box-shadow: 0 4px 8px rgba(0, 0, 0, 0.1);
}

.opcode-item.data { background-color: var(--opcode-data); }
.opcode-item.container { background-color: var(--opcode-container); }
.opcode-item.execution { background-color: var(--opcode-execution); }
.opcode-item.stack { background-color: var(--opcode-stack); }

.opcode-letter {
    font-size: 1.2rem;
    font-weight: bold;
    margin-bottom: 4px;
}

.opcode-name {
    font-size: 0.7rem;
    text-align: center;
    line-height: 1.2;
    overflow: hidden;
    text-overflow: ellipsis;
    display: -webkit-box;
    -webkit-line-clamp: 2;
    -webkit-box-orient: vertical;
    width: 100%;
    max-width: 100%;
}

.workspace {
    display: flex;
    flex-direction: column;
}

.payload-area {
    flex-grow: 1;
    position: relative;
    margin-bottom: 20px;
}

.start-marker, .end-marker {
    background-color: #eee;
    padding: 5px 10px;
    text-align: center;
    border-radius: 4px;
    font-weight: bold;
    color: #666;
}

.drop-area {
    min-height: 300px;
    border: 2px dashed var(--border-color);
    border-radius: 6px;
    margin: 10px 0;
    padding: 15px;
    display: flex;
    flex-direction: column;
    gap: 2px;
    background-color: rgba(245, 247, 250, 0.5);
}

.drop-area.highlight {
    border-color: var(--primary-color);
    background-color: rgba(58, 123, 213, 0.05);
}

.placed-opcode {
    display: flex;
    align-items: center;
    padding: 8px 12px;
    border-radius: 4px;
    color: white;
    position: relative;
    width: 100%;
}

.placed-opcode.data { background-color: var(--opcode-data); }
.placed-opcode.container { background-color: var(--opcode-container); }
.placed-opcode.execution { background-color: var(--opcode-execution); }
.placed-opcode.stack { background-color: var(--opcode-stack); }

.opcode-content {
    display: flex;
    align-items: center;
    flex-grow: 1;
    overflow: hidden;
}

.opcode-actions {
    display: flex;
    gap: 5px;
    flex-shrink: 0;
}

.edit-opcode, .delete-opcode {
    background: none;
    border: none;
    cursor: pointer;
    color: rgba(255, 255, 255, 0.8);
    font-size: 1rem;
    padding: 2px;
}

.edit-opcode:hover, .delete-opcode:hover {
    color: white;
}

.placed-opcode-letter {
    font-weight: bold;
    margin-right: 8px;
    font-size: 1.1rem;
    flex-shrink: 0;
}

.placed-opcode-params {
    font-size: 0.9rem;
    flex-grow: 1;
    white-space: nowrap;
    overflow: hidden;
    text-overflow: ellipsis;
}

.stack-visualization {
    margin-top: 20px;
}

.stack-preview {
    border: 1px solid var(--border-color);
    border-radius: 4px;
    padding: 10px;
    min-height: 100px;
    background-color: #fafafa;
}

.stack-item {
    padding: 5px;
    border: 1px solid #ddd;
    border-radius: 4px;
    margin-bottom: 5px;
    background-color: white;
}

#opcode-output {
    width: 100%;
    height: 200px;
    border: 1px solid var(--border-color);
    border-radius: 4px;
    padding: 10px;
    resize: vertical;
    font-family: monospace;
    margin-bottom: 15px;
}

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

.buttons button {
    padding: 8px 15px;
    border: none;
    border-radius: 4px;
    background-color: var(--primary-color);
    color: white;
    cursor: pointer;
    transition: background-color 0.2s;
}

.buttons button:hover {
    background-color: #2a62b3;
}

#clear-btn {
    background-color: #f44336;
}

#clear-btn:hover {
    background-color: #d32f2f;
}

.modal {
    display: none;
    position: fixed;
    top: 0;
    left: 0;
    width: 100%;
    height: 100%;
    background-color: rgba(0, 0, 0, 0.5);
    z-index: 100;
    justify-content: center;
    align-items: center;
}

.modal-content {
    background-color: var(--panel-bg);
    border-radius: 8px;
    padding: 20px;
    width: 90%;
    max-width: 500px;
    position: relative;
    max-height: 80vh;
    overflow-y: auto;
}

.close-btn {
    position: absolute;
    top: 10px;
    right: 15px;
    font-size: 1.5rem;
    cursor: pointer;
}

#modal-form {
    margin: 20px 0;
}

.form-group {
    margin-bottom: 15px;
}

.form-group label {
    display: block;
    margin-bottom: 5px;
    font-weight: 500;
}

.form-group input, .form-group textarea {
    width: 100%;
    padding: 8px;
    border: 1px solid var(--border-color);
    border-radius: 4px;
}

#apply-opcode {
    padding: 8px 15px;
    border: none;
    border-radius: 4px;
    background-color: var(--primary-color);
    color: white;
    cursor: pointer;
}

.opcode-desc {
    margin-bottom: 15px;
    line-height: 1.5;
    background-color: #f8f9fa;
    padding: 10px;
    border-radius: 4px;
    border-left: 4px solid var(--primary-color);
}

.opcode-effects {
    margin-bottom: 15px;
    background-color: #f0f4f8;
    padding: 10px;
    border-radius: 4px;
    font-size: 0.9rem;
}

.simulation-steps {
    max-height: 400px;
    overflow-y: auto;
    border: 1px solid var(--border-color);
    border-radius: 4px;
    padding: 10px;
    font-family: monospace;
    background-color: #fafafa;
}

.step {
    margin-bottom: 10px;
    padding-bottom: 10px;
    border-bottom: 1px dashed #ddd;
}

.step:last-child {
    border-bottom: none;
}

@media (max-width: 1200px) {
    .main-content {
        grid-template-columns: 1fr 1fr;
    }
    
    .output-panel {
        grid-column: span 2;
    }
}

@media (max-width: 768px) {
    .main-content {
        grid-template-columns: 1fr;
    }
    
    .output-panel {
        grid-column: span 1;
    }
}

/* Drop zone indicator styles */
.drop-zone-indicator {
    height: 1px;
    background-color: transparent;
    border-radius: 3px;
    margin: 4px 0;
    transition: all 0.2s;
    position: relative;
}

.drop-zone-indicator.active {
    height: 12px;
    background-color: rgba(58, 123, 213, 0.2);
    border: 2px dashed var(--primary-color);
}

/* Stack Visualization Styles */
.stack-visualization {
    margin-top: 20px;
    padding-top: 20px;
    border-top: 1px solid var(--border-color);
}

.stack-visualization h3 {
    margin-bottom: 15px;
    color: var(--primary-color);
    font-size: 1.2rem;
}

.stack-visualization h4 {
    margin-bottom: 10px;
    color: var(--primary-color);
    font-size: 1rem;
}

.simulation-controls {
    display: flex;
    gap: 10px;
    margin-bottom: 15px;
    flex-wrap: wrap;
}

.simulation-controls button {
    padding: 6px 12px;
    border: none;
    border-radius: 4px;
    background-color: var(--primary-color);
    color: white;
    cursor: pointer;
    transition: background-color 0.2s;
    font-size: 0.9rem;
}

.simulation-controls button:hover {
    background-color: #2a62b3;
}

#reset-btn {
    background-color: #f44336;
}

#reset-btn:hover {
    background-color: #d32f2f;
}

#step-btn {
    background-color: #ff9800;
}

#step-btn:hover {
    background-color: #f57c00;
}

.stack-container {
    display: flex;
    gap: 20px;
    margin-bottom: 15px;
}

.memo-panel, .stack-panel {
    flex: 1;
    border: 1px solid var(--border-color);
    border-radius: 6px;
    padding: 12px;
    background-color: #fafafa;
}

.memo-items, .stack-items {
    min-height: 200px;
    max-height: 300px;
    overflow-y: auto;
    display: flex;
    flex-direction: column-reverse;
    gap: 5px;
}

.memo-item, .stack-item {
    padding: 8px 10px;
    border-radius: 4px;
    background-color: white;
    border: 1px solid #e0e0e0;
    font-family: monospace;
    font-size: 0.9rem;
    word-break: break-all;
    display: flex;
    justify-content: space-between;
    margin-bottom: 5px;
}

.memo-key {
    font-weight: bold;
    margin-right: 5px;
    color: var(--primary-color);
}

.memo-value, .stack-value {
    overflow: hidden;
    text-overflow: ellipsis;
}

.simulation-log {
    height: 150px;
    max-height: 200px;
    overflow-y: auto;
    border: 1px solid var(--border-color);
    border-radius: 4px;
    padding: 10px;
    font-family: monospace;
    background-color: #fafafa;
    margin-top: 15px;
    white-space: pre-wrap;
}

.log-entry {
    margin-bottom: 5px;
    padding: 3px 0;
    border-bottom: 1px dashed #eee;
}

.log-entry.error {
    color: #f44336;
}

.log-entry.success {
    color: #4caf50;
}

/* Style for simulation step modal */
.simulation-steps {
    max-height: 400px;
    overflow-y: auto;
    padding: 10px;
    font-family: monospace;
    background-color: #fafafa;
    margin-bottom: 15px;
}

.step-opcode {
    font-weight: bold;
    color: var(--primary-color);
}

.step-stack-before, .step-stack-after {
    margin: 10px 0;
    padding: 8px;
    background-color: #f0f4f8;
    border-radius: 4px;
}

.step-stack-change {
    color: #4caf50;
    font-weight: bold;
}

.mark-indicator {
    color: #ff9800;
    font-weight: bold;
}

/* Highlight for current opcode being executed */
.placed-opcode.executing {
    box-shadow: 0 0 0 3px #ffeb3b;
    animation: pulse 1.5s infinite;
    position: relative;
    z-index: 5;
}

@keyframes pulse {
    0% { box-shadow: 0 0 0 3px rgba(255, 235, 59, 0.8); }
    50% { box-shadow: 0 0 0 5px rgba(255, 235, 59, 0.4); }
    100% { box-shadow: 0 0 0 3px rgba(255, 235, 59, 0.8); }
}

/* Step details directly in main UI */
.step-details {
    background-color: #f8f9fa;
    border: 1px solid var(--border-color);
    border-radius: 6px;
    padding: 12px;
    margin-bottom: 15px;
    box-shadow: 0 2px 5px rgba(0, 0, 0, 0.05);
}

.step-header {
    margin-bottom: 10px;
}

.step-header h4 {
    margin-bottom: 5px;
    color: var(--primary-color);
}

#step-description {
    font-family: monospace;
    padding: 5px;
    background-color: #f0f4f8;
    border-radius: 4px;
    color: #333;
}

/* Callable display enhancement */
.callable-name {
    font-weight: bold;
    color: var(--opcode-execution);
}

.function-result {
    color: var(--opcode-execution);
    font-style: italic;
}

/* Buttons for step-by-step control */
#next-step-btn, #finish-simulation-btn {
    background-color: #ff9800;
}

#next-step-btn:hover, #finish-simulation-btn:hover {
    background-color: #f57c00;
}

/* Enhanced step details display */
.step-stack-effect {
    margin-top: 10px;
    padding: 8px;
    background-color: #f0f4f8;
    border-radius: 6px;
    border-left: 3px solid var(--primary-color);
}

.step-stack-effect div {
    margin-bottom: 8px;
    padding: 5px;
    background-color: rgba(255, 255, 255, 0.7);
    border-radius: 4px;
    font-family: monospace;
    word-break: break-all;
}

.step-stack-effect div:last-child {
    margin-bottom: 0;
}

/* Make callable names and function results more prominent */
.callable-name {
    font-weight: bold;
    color: #e91e63;
    background-color: rgba(233, 30, 99, 0.1);
    padding: 2px 4px;
    border-radius: 3px;
}

.function-result {
    font-weight: bold;
    color: #4caf50;
    background-color: rgba(76, 175, 80, 0.1);
    padding: 2px 4px;
    border-radius: 3px;
}

.mark-indicator {
    font-weight: bold;
    color: #ff9800;
    background-color: rgba(255, 152, 0, 0.1);
    padding: 2px 4px;
    border-radius: 3px;
}

/* Make stack item display clearer */
.stack-item, .memo-item {
    padding: 8px 10px;
    border-radius: 4px;
    background-color: white;
    border: 1px solid #e0e0e0;
    font-family: monospace;
    font-size: 0.9rem;
    word-break: break-all;
    display: flex;
    justify-content: space-between;
    margin-bottom: 5px;
}

.stack-item:hover, .memo-item:hover {
    background-color: #f5f5f5;
    box-shadow: 0 1px 3px rgba(0,0,0,0.1);
}

.stack-value, .memo-value {
    flex-grow: 1;
    overflow: auto;
    max-height: 100px;
}

.stack-index, .memo-key {
    color: #777;
    margin-left: 8px;
    font-weight: bold;
    flex-shrink: 0;
}