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

:root {
    --primary-color: #2563eb;
    --primary-dark: #1d4ed8;
    --success-color: #16a34a;
    --warning-color: #ea580c;
    --danger-color: #dc2626;
    --bg-color: #0f172a;
    --surface-color: #1e293b;
    --surface-light: #334155;
    --text-color: #f1f5f9;
    --text-muted: #94a3b8;
    --border-color: #475569;
    --accent-color: #06b6d4;
}

body {
    font-family: 'Segoe UI', Tahoma, Geneva, Verdana, sans-serif;
    background: var(--bg-color);
    color: var(--text-color);
    min-height: 100vh;
    line-height: 1.6;
}

header {
    background: linear-gradient(135deg, var(--primary-color), var(--accent-color));
    padding: 2rem;
    text-align: center;
    box-shadow: 0 4px 20px rgba(0, 0, 0, 0.3);
}

header h1 {
    font-size: 2.5rem;
    margin-bottom: 0.5rem;
}

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

/* Navigation Tabs */
.tabs {
    display: flex;
    justify-content: center;
    gap: 0.5rem;
    padding: 1rem;
    background: var(--surface-color);
    flex-wrap: wrap;
}

.tab-btn {
    padding: 0.75rem 1.5rem;
    border: none;
    background: transparent;
    color: var(--text-muted);
    cursor: pointer;
    font-size: 1rem;
    border-radius: 8px;
    transition: all 0.3s ease;
}

.tab-btn:hover {
    background: var(--surface-light);
    color: var(--text-color);
}

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

/* Main Content */
main {
    max-width: 1600px;
    margin: 0 auto;
    padding: 1rem;
}

.tab-content {
    display: none;
}

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

/* Buttons */
.btn {
    padding: 0.6rem 1.2rem;
    border: none;
    border-radius: 6px;
    cursor: pointer;
    font-size: 0.95rem;
    font-weight: 500;
    transition: all 0.2s ease;
    background: var(--surface-light);
    color: var(--text-color);
}

.btn:hover {
    transform: translateY(-2px);
    box-shadow: 0 4px 12px rgba(0, 0, 0, 0.3);
}

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

.btn.primary:hover {
    background: var(--primary-dark);
}

.btn.success {
    background: var(--success-color);
}

.btn.warning {
    background: var(--warning-color);
}

.btn.danger {
    background: var(--danger-color);
}

.btn.small {
    padding: 0.4rem 0.8rem;
    font-size: 0.85rem;
}

.button-group {
    display: flex;
    gap: 0.5rem;
    margin-top: 1rem;
    flex-wrap: wrap;
}

/* Editor Section */
.editor-container {
    display: grid;
    grid-template-columns: 1fr 1fr;
    gap: 1.5rem;
    margin-bottom: 1.5rem;
}

@media (max-width: 1024px) {
    .editor-container {
        grid-template-columns: 1fr;
    }
}

.code-section h2,
.output-section h2 {
    margin-bottom: 0.75rem;
    color: var(--accent-color);
}

#code-input {
    width: 100%;
    height: 300px;
    padding: 1rem;
    font-family: 'Consolas', 'Monaco', monospace;
    font-size: 14px;
    background: var(--surface-color);
    border: 2px solid var(--border-color);
    border-radius: 8px;
    color: var(--text-color);
    resize: vertical;
}

#code-input:focus {
    outline: none;
    border-color: var(--primary-color);
}

.output-box {
    background: var(--surface-color);
    border: 2px solid var(--border-color);
    border-radius: 8px;
    padding: 1rem;
    font-family: 'Consolas', monospace;
    font-size: 13px;
    height: 140px;
    overflow-y: auto;
    margin-bottom: 1rem;
}

.output-box:last-child {
    margin-bottom: 0;
}

/* Registers and Memory */
.registers-memory {
    display: grid;
    grid-template-columns: 1fr 1fr;
    gap: 1.5rem;
}

@media (max-width: 900px) {
    .registers-memory {
        grid-template-columns: 1fr;
    }
}

.registers,
.quick-memory {
    background: var(--surface-color);
    padding: 1.5rem;
    border-radius: 12px;
    border: 2px solid var(--border-color);
}

.registers h2,
.registers h3,
.quick-memory h2 {
    margin-bottom: 1rem;
    color: var(--accent-color);
}

.register-grid {
    display: grid;
    grid-template-columns: repeat(4, 1fr);
    gap: 0.75rem;
    margin-bottom: 1rem;
}

.register {
    background: var(--surface-light);
    padding: 0.75rem;
    border-radius: 8px;
    text-align: center;
    border: 1px solid var(--border-color);
}

.register.wide {
    grid-column: span 2;
}

.reg-name {
    display: block;
    font-size: 0.85rem;
    color: var(--text-muted);
    margin-bottom: 0.25rem;
}

.reg-value {
    font-family: 'Consolas', monospace;
    font-size: 1.25rem;
    font-weight: bold;
    color: var(--accent-color);
}

.special-registers {
    display: grid;
    grid-template-columns: 1fr 1fr;
    gap: 0.75rem;
    margin-bottom: 1rem;
}

.flags {
    display: flex;
    gap: 0.5rem;
    flex-wrap: wrap;
}

.flag {
    background: var(--surface-light);
    padding: 0.5rem 0.75rem;
    border-radius: 6px;
    text-align: center;
    min-width: 50px;
    border: 1px solid var(--border-color);
}

.flag-name {
    display: block;
    font-size: 0.75rem;
    color: var(--text-muted);
}

.flag-value {
    font-family: 'Consolas', monospace;
    font-weight: bold;
    color: var(--warning-color);
}

.flag-value.set {
    color: var(--success-color);
}

.memory-controls {
    display: flex;
    gap: 0.5rem;
    align-items: center;
    margin-bottom: 1rem;
    flex-wrap: wrap;
}

.memory-controls input {
    width: 80px;
    padding: 0.4rem;
    font-family: 'Consolas', monospace;
    background: var(--surface-light);
    border: 1px solid var(--border-color);
    border-radius: 4px;
    color: var(--text-color);
    text-transform: uppercase;
}

.memory-grid {
    display: grid;
    grid-template-columns: repeat(auto-fill, minmax(70px, 1fr));
    gap: 0.5rem;
    max-height: 300px;
    overflow-y: auto;
}

.memory-cell {
    background: var(--surface-light);
    padding: 0.5rem;
    border-radius: 4px;
    text-align: center;
    font-family: 'Consolas', monospace;
    font-size: 0.8rem;
    border: 1px solid var(--border-color);
}

.memory-cell .addr {
    display: block;
    color: var(--text-muted);
    font-size: 0.7rem;
}

.memory-cell .data {
    color: var(--accent-color);
    font-weight: bold;
}

/* Instructions Tab */
.instructions-container {
    background: var(--surface-color);
    padding: 1.5rem;
    border-radius: 12px;
}

.search-box {
    margin-bottom: 1rem;
}

.search-box input {
    width: 100%;
    padding: 0.75rem 1rem;
    font-size: 1rem;
    background: var(--surface-light);
    border: 2px solid var(--border-color);
    border-radius: 8px;
    color: var(--text-color);
}

.search-box input:focus {
    outline: none;
    border-color: var(--primary-color);
}

.instruction-categories {
    display: flex;
    gap: 0.5rem;
    margin-bottom: 1.5rem;
    flex-wrap: wrap;
}

.cat-btn {
    padding: 0.5rem 1rem;
    border: 1px solid var(--border-color);
    background: transparent;
    color: var(--text-muted);
    border-radius: 20px;
    cursor: pointer;
    font-size: 0.9rem;
    transition: all 0.2s ease;
}

.cat-btn:hover {
    background: var(--surface-light);
    color: var(--text-color);
}

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

.instruction-list {
    display: grid;
    grid-template-columns: repeat(auto-fill, minmax(280px, 1fr));
    gap: 1rem;
    max-height: 600px;
    overflow-y: auto;
}

.instruction-card {
    background: var(--surface-light);
    padding: 1rem;
    border-radius: 8px;
    border: 1px solid var(--border-color);
    transition: all 0.2s ease;
}

.instruction-card:hover {
    border-color: var(--primary-color);
    transform: translateY(-2px);
}

.instruction-card .mnemonic {
    font-family: 'Consolas', monospace;
    font-size: 1.1rem;
    font-weight: bold;
    color: var(--accent-color);
    margin-bottom: 0.5rem;
}

.instruction-card .opcode {
    font-family: 'Consolas', monospace;
    font-size: 0.85rem;
    color: var(--warning-color);
    margin-bottom: 0.5rem;
}

.instruction-card .description {
    font-size: 0.9rem;
    color: var(--text-muted);
    margin-bottom: 0.5rem;
}

.instruction-card .category-tag {
    display: inline-block;
    padding: 0.2rem 0.5rem;
    background: var(--primary-color);
    border-radius: 4px;
    font-size: 0.75rem;
}

/* Converter Tab */
.converter-container {
    max-width: 800px;
    margin: 0 auto;
    background: var(--surface-color);
    padding: 2rem;
    border-radius: 12px;
}

.converter-container h2 {
    text-align: center;
    margin-bottom: 1.5rem;
    color: var(--accent-color);
}

.converter-box {
    display: grid;
    grid-template-columns: repeat(auto-fit, minmax(200px, 1fr));
    gap: 1rem;
    margin-bottom: 1.5rem;
}

.converter-input {
    background: var(--surface-light);
    padding: 1rem;
    border-radius: 8px;
}

.converter-input label {
    display: block;
    margin-bottom: 0.5rem;
    color: var(--text-muted);
    font-size: 0.9rem;
}

.converter-input input {
    width: 100%;
    padding: 0.75rem;
    font-family: 'Consolas', monospace;
    font-size: 1.1rem;
    background: var(--surface-color);
    border: 2px solid var(--border-color);
    border-radius: 6px;
    color: var(--text-color);
    text-transform: uppercase;
}

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

.converter-actions {
    text-align: center;
    margin-bottom: 2rem;
}

.quick-ref {
    background: var(--surface-light);
    padding: 1.5rem;
    border-radius: 8px;
}

.quick-ref h3 {
    margin-bottom: 1rem;
    color: var(--accent-color);
}

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

.ref-table th,
.ref-table td {
    padding: 0.5rem;
    text-align: center;
    border: 1px solid var(--border-color);
}

.ref-table th {
    background: var(--surface-color);
    color: var(--accent-color);
}

.ref-table td {
    font-family: 'Consolas', monospace;
}

/* Memory Editor Tab */
.memory-editor-container {
    background: var(--surface-color);
    padding: 1.5rem;
    border-radius: 12px;
}

.memory-editor-container h2 {
    color: var(--accent-color);
    margin-bottom: 1rem;
}

.memory-editor-container h3 {
    color: var(--text-muted);
    margin-bottom: 0.75rem;
    font-size: 1rem;
}

.memory-controls-main {
    display: flex;
    gap: 1rem;
    align-items: flex-end;
    margin-bottom: 1.5rem;
    flex-wrap: wrap;
}

.control-group {
    display: flex;
    flex-direction: column;
    gap: 0.25rem;
}

.control-group label {
    font-size: 0.85rem;
    color: var(--text-muted);
}

.control-group input {
    padding: 0.5rem;
    font-family: 'Consolas', monospace;
    background: var(--surface-light);
    border: 1px solid var(--border-color);
    border-radius: 4px;
    color: var(--text-color);
    text-transform: uppercase;
    width: 100px;
}

.memory-input-section,
.memory-bulk-input {
    background: var(--surface-light);
    padding: 1rem;
    border-radius: 8px;
    margin-bottom: 1rem;
}

.memory-input-controls {
    display: flex;
    gap: 1rem;
    align-items: flex-end;
    flex-wrap: wrap;
}

#bulk-data {
    width: 100%;
    height: 100px;
    padding: 0.75rem;
    font-family: 'Consolas', monospace;
    background: var(--surface-color);
    border: 1px solid var(--border-color);
    border-radius: 6px;
    color: var(--text-color);
    resize: vertical;
    margin-bottom: 0.75rem;
}

.memory-table-container {
    max-height: 400px;
    overflow: auto;
    border: 1px solid var(--border-color);
    border-radius: 8px;
}

.memory-table {
    width: 100%;
    border-collapse: collapse;
    font-family: 'Consolas', monospace;
    font-size: 0.85rem;
}

.memory-table th,
.memory-table td {
    padding: 0.5rem;
    text-align: center;
    border: 1px solid var(--border-color);
}

.memory-table th {
    background: var(--surface-light);
    color: var(--accent-color);
    position: sticky;
    top: 0;
}

.memory-table td:first-child {
    background: var(--surface-light);
    color: var(--text-muted);
    font-weight: bold;
}

.memory-table td.highlight {
    background: var(--primary-color);
    color: white;
}

.memory-table td.pc-highlight {
    background: var(--success-color);
    color: white;
}

/* Footer */
footer {
    text-align: center;
    padding: 1.5rem;
    color: var(--text-muted);
    border-top: 1px solid var(--border-color);
    margin-top: 2rem;
}

/* Scrollbar Styling */
::-webkit-scrollbar {
    width: 8px;
    height: 8px;
}

::-webkit-scrollbar-track {
    background: var(--surface-color);
}

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

::-webkit-scrollbar-thumb:hover {
    background: var(--text-muted);
}

/* Execution Log Styling */
.log-entry {
    padding: 0.25rem 0;
    border-bottom: 1px solid var(--border-color);
}

.log-entry:last-child {
    border-bottom: none;
}

.log-entry.error {
    color: var(--danger-color);
}

.log-entry.success {
    color: var(--success-color);
}

.log-entry.info {
    color: var(--accent-color);
}

/* Machine Code Output */
.machine-code-line {
    display: flex;
    gap: 1rem;
    padding: 0.25rem 0;
}

.machine-code-line .address {
    color: var(--text-muted);
    min-width: 50px;
}

.machine-code-line .bytes {
    color: var(--warning-color);
}

.machine-code-line .instruction {
    color: var(--accent-color);
}

/* Animation */
@keyframes pulse {
    0%, 100% {
        box-shadow: 0 0 0 0 rgba(37, 99, 235, 0.4);
    }
    50% {
        box-shadow: 0 0 0 10px rgba(37, 99, 235, 0);
    }
}

.register.active {
    animation: pulse 1s ease-in-out;
    border-color: var(--primary-color);
}