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

:root {
    --bg-primary: #1a1b26;
    --bg-secondary: #24283b;
    --bg-tertiary: #2f334d;
    --bg-editor: #1e2030;
    --text-primary: #c0caf5;
    --text-secondary: #a9b1d6;
    --text-muted: #565f89;
    --accent-blue: #7aa2f7;
    --accent-green: #9ece6a;
    --accent-red: #f7768e;
    --accent-yellow: #e0af68;
    --accent-purple: #bb9af7;
    --accent-cyan: #7dcfff;
    --accent-orange: #ff9e64;
    --border-color: #3b4261;
    --led-on: #22c55e;
    --led-off: #1e3a2a;
    --led-glow: 0 0 12px #22c55e, 0 0 24px rgba(34, 197, 94, 0.4);
    --flag-on: #7aa2f7;
    --flag-off: #3b4261;
    --highlight-line: rgba(122, 162, 247, 0.12);
    --scrollbar-thumb: #3b4261;
    --scrollbar-track: #1a1b26;
}

html, body {
    height: 100%;
    font-family: 'Segoe UI', system-ui, -apple-system, sans-serif;
    font-size: 14px;
    background: var(--bg-primary);
    color: var(--text-primary);
    overflow: hidden;
}

/* ---- TOOLBAR ---- */
#toolbar {
    display: flex;
    align-items: center;
    gap: 16px;
    padding: 8px 16px;
    background: var(--bg-secondary);
    border-bottom: 1px solid var(--border-color);
    height: 52px;
    flex-shrink: 0;
}

.toolbar-left {
    flex-shrink: 0;
}

.logo {
    font-size: 18px;
    font-weight: 700;
    color: var(--accent-blue);
    letter-spacing: 0.5px;
}

.logo-sub {
    font-size: 11px;
    color: var(--text-muted);
    font-weight: 400;
}

.toolbar-center {
    display: flex;
    align-items: center;
    gap: 8px;
    flex: 1;
}

.toolbar-right {
    display: flex;
    align-items: center;
    gap: 8px;
    flex-shrink: 0;
}

.toolbar-right label {
    color: var(--text-muted);
    font-size: 12px;
}

button {
    padding: 6px 16px;
    border: 1px solid var(--border-color);
    border-radius: 4px;
    background: var(--bg-tertiary);
    color: var(--text-primary);
    font-size: 13px;
    cursor: pointer;
    transition: all 0.15s ease;
    font-family: inherit;
}

button:hover:not(:disabled) {
    background: var(--accent-blue);
    color: #1a1b26;
    border-color: var(--accent-blue);
}

button:disabled {
    opacity: 0.4;
    cursor: not-allowed;
}

button:active:not(:disabled) {
    transform: scale(0.97);
}

#btn-assemble {
    background: var(--accent-blue);
    color: #1a1b26;
    border-color: var(--accent-blue);
    font-weight: 600;
}

#btn-assemble:hover {
    background: #89b4fa;
}

#btn-run {
    background: var(--accent-green);
    color: #1a1b26;
    border-color: var(--accent-green);
}

#btn-run:hover:not(:disabled) {
    background: #a9de7a;
    border-color: #a9de7a;
}

#btn-stop {
    background: var(--accent-red);
    color: #1a1b26;
    border-color: var(--accent-red);
}

#btn-stop:hover:not(:disabled) {
    background: #f99;
    border-color: #f99;
}

.speed-control {
    display: flex;
    align-items: center;
    gap: 6px;
    margin-left: 8px;
}

.speed-control label {
    color: var(--text-muted);
    font-size: 12px;
}

#speed-slider {
    width: 80px;
    accent-color: var(--accent-blue);
}

select {
    padding: 5px 8px;
    border: 1px solid var(--border-color);
    border-radius: 4px;
    background: var(--bg-tertiary);
    color: var(--text-primary);
    font-size: 13px;
    font-family: inherit;
    cursor: pointer;
}

select:focus, button:focus, input:focus, textarea:focus {
    outline: 1px solid var(--accent-blue);
    outline-offset: -1px;
}

/* ---- MAIN LAYOUT ---- */
#app {
    display: grid;
    grid-template-columns: 1fr 340px;
    grid-template-rows: 1fr auto auto;
    height: calc(100vh - 52px);
    gap: 1px;
    background: var(--border-color);
}

#editor-panel {
    grid-row: 1 / 2;
    grid-column: 1 / 2;
    display: flex;
    flex-direction: column;
    background: var(--bg-primary);
    min-height: 0;
}

#right-panels {
    grid-row: 1 / 2;
    grid-column: 2 / 3;
    display: flex;
    flex-direction: column;
    gap: 1px;
    background: var(--border-color);
    overflow-y: auto;
    min-height: 0;
}

#memory-panel {
    grid-row: 2 / 3;
    grid-column: 1 / -1;
    background: var(--bg-primary);
    max-height: 200px;
}

#console-panel {
    grid-row: 3 / 4;
    grid-column: 1 / -1;
    background: var(--bg-primary);
    max-height: 150px;
}

/* ---- PANELS ---- */
.panel {
    background: var(--bg-primary);
    display: flex;
    flex-direction: column;
}

.panel-header {
    display: flex;
    align-items: center;
    justify-content: space-between;
    padding: 6px 12px;
    background: var(--bg-secondary);
    color: var(--text-muted);
    font-size: 11px;
    font-weight: 600;
    text-transform: uppercase;
    letter-spacing: 1px;
    flex-shrink: 0;
    border-bottom: 1px solid var(--border-color);
    user-select: none;
}

.panel-body {
    padding: 8px 12px;
    flex: 1;
    overflow: auto;
    min-height: 0;
}

/* ---- EDITOR ---- */
#editor-container {
    display: flex;
    flex: 1;
    min-height: 0;
    position: relative;
    overflow: hidden;
}

#line-numbers {
    width: 44px;
    padding: 10px 6px 10px 0;
    text-align: right;
    font-family: 'Cascadia Code', 'Consolas', 'Courier New', monospace;
    font-size: 13px;
    line-height: 1.6;
    color: var(--text-muted);
    background: var(--bg-secondary);
    border-right: 1px solid var(--border-color);
    overflow: hidden;
    user-select: none;
    flex-shrink: 0;
}

#code-editor {
    flex: 1;
    padding: 10px 12px;
    background: var(--bg-editor);
    color: var(--text-primary);
    border: none;
    resize: none;
    font-family: 'Cascadia Code', 'Consolas', 'Courier New', monospace;
    font-size: 13px;
    line-height: 1.6;
    tab-size: 4;
    white-space: pre;
    overflow: auto;
}

#code-editor::placeholder {
    color: var(--text-muted);
}

#code-editor:focus {
    outline: none;
}

.line-highlight {
    background: var(--highlight-line) !important;
}

/* ---- REGISTERS ---- */
#registers-body {
    display: flex;
    flex-direction: column;
    gap: 6px;
    padding: 8px 10px;
}

.reg-group {
    display: flex;
    flex-direction: column;
    gap: 2px;
}

.reg-group + .reg-group {
    border-top: 1px solid var(--border-color);
    padding-top: 6px;
}

.reg-row {
    display: flex;
    align-items: center;
    gap: 6px;
    font-family: 'Cascadia Code', 'Consolas', monospace;
    font-size: 13px;
    height: 22px;
}

.reg-name {
    color: var(--accent-cyan);
    font-weight: 600;
    width: 24px;
    text-align: right;
}

.reg-val {
    background: var(--bg-tertiary);
    padding: 1px 6px;
    border-radius: 3px;
    color: var(--accent-yellow);
    min-width: 44px;
    text-align: center;
    font-size: 13px;
    transition: color 0.2s;
}

.reg-val.small {
    min-width: 28px;
    font-size: 12px;
    color: var(--text-secondary);
}

.reg-val.changed {
    color: var(--accent-green);
}

.reg-byte-label {
    color: var(--text-muted);
    font-size: 10px;
    margin-left: 4px;
}

/* ---- FLAGS ---- */
#flags-body {
    display: flex;
    gap: 8px;
    flex-wrap: wrap;
    padding: 8px 10px;
}

.flag {
    display: flex;
    flex-direction: column;
    align-items: center;
    gap: 2px;
    padding: 4px 10px;
    border-radius: 4px;
    background: var(--bg-tertiary);
    min-width: 40px;
    transition: background 0.2s;
}

.flag.active {
    background: var(--flag-on);
}

.flag.active .flag-name,
.flag.active .flag-val {
    color: #1a1b26;
}

.flag-name {
    font-size: 10px;
    font-weight: 700;
    color: var(--text-muted);
    font-family: 'Cascadia Code', 'Consolas', monospace;
}

.flag-val {
    font-size: 14px;
    font-weight: 700;
    color: var(--text-secondary);
    font-family: 'Cascadia Code', 'Consolas', monospace;
}

/* ---- LEDs ---- */
#led-body {
    padding: 12px;
    display: flex;
    flex-direction: column;
    align-items: center;
    gap: 8px;
}

.led-row {
    display: flex;
    gap: 10px;
}

.led {
    width: 32px;
    height: 32px;
    border-radius: 50%;
    background: var(--led-off);
    border: 2px solid #2d4a35;
    display: flex;
    align-items: center;
    justify-content: center;
    transition: all 0.15s ease;
    position: relative;
}

.led.on {
    background: var(--led-on);
    border-color: var(--led-on);
    box-shadow: var(--led-glow);
}

.led-bit {
    font-size: 10px;
    font-weight: 700;
    color: var(--text-muted);
    font-family: 'Cascadia Code', 'Consolas', monospace;
}

.led.on .led-bit {
    color: #052e16;
}

.led-value {
    font-family: 'Cascadia Code', 'Consolas', monospace;
    font-size: 12px;
    color: var(--text-muted);
}

#led-hex {
    color: var(--accent-yellow);
}

#led-dec {
    color: var(--text-secondary);
}

/* ---- I/O ---- */
#io-body {
    padding: 8px 10px;
}

.io-row {
    display: flex;
    align-items: center;
    gap: 8px;
    font-size: 13px;
}

.io-row label {
    color: var(--text-secondary);
    font-size: 12px;
}

.hex-input {
    width: 48px;
    padding: 3px 6px;
    border: 1px solid var(--border-color);
    border-radius: 3px;
    background: var(--bg-tertiary);
    color: var(--accent-yellow);
    font-family: 'Cascadia Code', 'Consolas', monospace;
    font-size: 13px;
    text-align: center;
    text-transform: uppercase;
}

.io-hint {
    color: var(--text-muted);
    font-size: 10px;
}

/* ---- STACK ---- */
#stack-body {
    padding: 6px 10px;
    max-height: 160px;
    overflow-y: auto;
}

#stack-content {
    font-family: 'Cascadia Code', 'Consolas', monospace;
    font-size: 12px;
    line-height: 1.6;
}

.stack-entry {
    display: flex;
    gap: 12px;
    color: var(--text-secondary);
}

.stack-entry .stack-addr {
    color: var(--text-muted);
}

.stack-entry .stack-val {
    color: var(--accent-yellow);
}

.stack-entry.sp-pointer {
    color: var(--accent-green);
    font-weight: 700;
}

.stack-entry.sp-pointer .stack-addr {
    color: var(--accent-green);
}

.stack-empty {
    color: var(--text-muted);
    font-style: italic;
    font-size: 12px;
}

/* ---- MEMORY ---- */
.memory-controls {
    display: flex;
    align-items: center;
    gap: 6px;
    font-size: 12px;
}

.memory-controls label {
    color: var(--text-muted);
}

.memory-controls .hex-input {
    width: 52px;
}

.memory-controls button {
    padding: 2px 10px;
    font-size: 11px;
}

.memory-controls select {
    font-size: 11px;
    padding: 2px 6px;
}

#memory-body {
    padding: 6px 10px;
    overflow: auto;
    max-height: 170px;
}

#memory-dump {
    font-family: 'Cascadia Code', 'Consolas', monospace;
    font-size: 12px;
    line-height: 1.5;
    color: var(--text-secondary);
    white-space: pre;
    margin: 0;
}

.mem-addr {
    color: var(--accent-cyan);
}

.mem-val {
    color: var(--text-secondary);
}

.mem-val-nonzero {
    color: var(--accent-yellow);
}

.mem-ascii {
    color: var(--text-muted);
}

/* ---- CONSOLE ---- */
#console-body {
    max-height: 120px;
    overflow-y: auto;
    padding: 6px 10px;
}

#console-output {
    font-family: 'Cascadia Code', 'Consolas', monospace;
    font-size: 12px;
    line-height: 1.5;
    white-space: pre-wrap;
    word-break: break-all;
}

.console-error {
    color: var(--accent-red);
}

.console-info {
    color: var(--accent-blue);
}

.console-success {
    color: var(--accent-green);
}

.console-warn {
    color: var(--accent-yellow);
}

.small-btn {
    padding: 2px 8px;
    font-size: 10px;
}

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

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

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

::-webkit-scrollbar-thumb:hover {
    background: #565f89;
}

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

/* Line number sync with editor */
#line-numbers div {
    height: 1.6em;
    line-height: 1.6;
}

.current-line {
    background: var(--highlight-line);
}

/* ---- HELP BUTTON ---- */
#btn-help {
    background: var(--accent-purple);
    color: #1a1b26;
    border-color: var(--accent-purple);
    font-weight: 600;
    margin-left: 8px;
}

#btn-help:hover {
    background: #cba6ff;
    border-color: #cba6ff;
}

/* ---- HELP MODAL ---- */
.help-modal-overlay {
    position: fixed;
    inset: 0;
    z-index: 1000;
    background: rgba(0, 0, 0, 0.7);
    display: flex;
    align-items: center;
    justify-content: center;
    animation: helpFadeIn 0.2s ease;
}

@keyframes helpFadeIn {
    from { opacity: 0; }
    to { opacity: 1; }
}

.help-modal {
    width: 90vw;
    max-width: 960px;
    height: 85vh;
    background: var(--bg-primary);
    border: 1px solid var(--border-color);
    border-radius: 8px;
    display: flex;
    flex-direction: column;
    overflow: hidden;
    box-shadow: 0 20px 60px rgba(0, 0, 0, 0.5);
}

.help-modal-header {
    display: flex;
    align-items: center;
    justify-content: space-between;
    padding: 12px 20px;
    background: var(--bg-secondary);
    border-bottom: 1px solid var(--border-color);
    flex-shrink: 0;
}

.help-modal-header h2 {
    font-size: 16px;
    font-weight: 700;
    color: var(--accent-blue);
}

.help-close-btn {
    width: 32px;
    height: 32px;
    padding: 0;
    font-size: 20px;
    line-height: 1;
    display: flex;
    align-items: center;
    justify-content: center;
    border-radius: 4px;
    background: var(--bg-tertiary);
    color: var(--text-primary);
    border: 1px solid var(--border-color);
}

.help-close-btn:hover {
    background: var(--accent-red);
    color: #1a1b26;
    border-color: var(--accent-red);
}

.help-modal-content {
    display: flex;
    flex: 1;
    min-height: 0;
}

.help-sidebar {
    width: 220px;
    flex-shrink: 0;
    background: var(--bg-secondary);
    border-right: 1px solid var(--border-color);
    overflow-y: auto;
    padding: 8px 0;
}

.help-sidebar-item {
    display: block;
    width: 100%;
    padding: 10px 16px;
    border: none;
    background: none;
    color: var(--text-secondary);
    font-size: 13px;
    text-align: left;
    cursor: pointer;
    transition: all 0.15s;
    border-left: 3px solid transparent;
}

.help-sidebar-item:hover {
    background: var(--bg-tertiary);
    color: var(--text-primary);
    border-color: transparent;
}

.help-sidebar-item.active {
    background: var(--bg-tertiary);
    color: var(--accent-blue);
    border-left-color: var(--accent-blue);
    font-weight: 600;
}

.help-sidebar-label {
    padding: 4px 16px 2px;
    font-size: 10px;
    font-weight: 700;
    letter-spacing: 1.2px;
    color: var(--accent-purple);
    text-transform: uppercase;
    user-select: none;
}

.help-sidebar-divider {
    height: 1px;
    background: var(--border-color);
    margin: 6px 12px;
}

.help-body {
    flex: 1;
    padding: 24px 28px;
    overflow-y: auto;
    line-height: 1.7;
}

.help-body h3 {
    font-size: 20px;
    font-weight: 700;
    color: var(--accent-blue);
    margin-bottom: 12px;
}

.help-body h4 {
    font-size: 15px;
    font-weight: 600;
    color: var(--accent-cyan);
    margin-top: 20px;
    margin-bottom: 8px;
}

.help-body p {
    margin-bottom: 12px;
    color: var(--text-secondary);
}

.help-body ul, .help-body ol {
    margin: 0 0 12px 20px;
    color: var(--text-secondary);
}

.help-body li {
    margin-bottom: 4px;
}

.help-body strong {
    color: var(--text-primary);
}

.help-body code {
    background: var(--bg-tertiary);
    padding: 1px 6px;
    border-radius: 3px;
    font-family: 'Cascadia Code', 'Consolas', monospace;
    font-size: 13px;
    color: var(--accent-yellow);
}

.help-body pre {
    background: var(--bg-editor);
    border: 1px solid var(--border-color);
    border-radius: 6px;
    padding: 12px 16px;
    margin: 10px 0 16px;
    overflow-x: auto;
    font-family: 'Cascadia Code', 'Consolas', monospace;
    font-size: 13px;
    line-height: 1.6;
    color: var(--text-primary);
}

.help-body pre .cmt {
    color: var(--accent-green);
}

.help-body pre .kw {
    color: var(--accent-purple);
}

.help-body pre .reg {
    color: var(--accent-cyan);
}

.help-body pre .num {
    color: var(--accent-orange);
}

.help-body pre .lbl {
    color: var(--accent-yellow);
}

.help-body .help-table {
    width: 100%;
    border-collapse: collapse;
    margin: 10px 0 16px;
    font-size: 13px;
}

.help-body .help-table th {
    background: var(--bg-secondary);
    padding: 8px 12px;
    text-align: left;
    font-weight: 600;
    color: var(--accent-cyan);
    border: 1px solid var(--border-color);
}

.help-body .help-table td {
    padding: 6px 12px;
    border: 1px solid var(--border-color);
    color: var(--text-secondary);
}

.help-body .help-table td code {
    white-space: nowrap;
}

.help-body .tip-box {
    background: rgba(122, 162, 247, 0.1);
    border-left: 3px solid var(--accent-blue);
    padding: 10px 14px;
    margin: 12px 0;
    border-radius: 0 6px 6px 0;
    color: var(--text-secondary);
}

.help-body .warn-box {
    background: rgba(247, 118, 142, 0.1);
    border-left: 3px solid var(--accent-red);
    padding: 10px 14px;
    margin: 12px 0;
    border-radius: 0 6px 6px 0;
    color: var(--text-secondary);
}

/* ---- QUIZ ---- */
.quiz-container {
    margin-top: 16px;
}

.quiz-card {
    background: var(--bg-secondary);
    border: 1px solid var(--border-color);
    border-radius: 6px;
    padding: 16px 20px;
    margin-bottom: 12px;
    cursor: pointer;
    transition: border-color 0.15s;
}

.quiz-card:hover {
    border-color: var(--accent-blue);
}

.quiz-card h4 {
    margin: 0 0 4px;
    color: var(--accent-blue);
}

.quiz-card p {
    margin: 0;
    font-size: 13px;
    color: var(--text-muted);
}

.quiz-question {
    margin-bottom: 20px;
    padding-bottom: 16px;
    border-bottom: 1px solid var(--border-color);
}

.quiz-question:last-of-type {
    border-bottom: none;
}

.quiz-question p {
    font-weight: 600;
    color: var(--text-primary);
    margin-bottom: 10px;
}

.quiz-option {
    display: flex;
    align-items: center;
    gap: 8px;
    padding: 6px 10px;
    margin: 4px 0;
    border-radius: 4px;
    cursor: pointer;
    transition: background 0.1s;
    color: var(--text-secondary);
    font-size: 13px;
}

.quiz-option:hover {
    background: var(--bg-tertiary);
}

.quiz-option input[type="radio"] {
    accent-color: var(--accent-blue);
}

.quiz-feedback {
    margin-top: 6px;
    padding: 8px 12px;
    border-radius: 4px;
    font-size: 13px;
    display: none;
}

.quiz-feedback.correct {
    display: block;
    background: rgba(158, 206, 106, 0.15);
    color: var(--accent-green);
    border: 1px solid rgba(158, 206, 106, 0.3);
}

.quiz-feedback.wrong {
    display: block;
    background: rgba(247, 118, 142, 0.15);
    color: var(--accent-red);
    border: 1px solid rgba(247, 118, 142, 0.3);
}

.quiz-btn {
    margin-top: 16px;
    padding: 8px 20px;
    background: var(--accent-blue);
    color: #1a1b26;
    border: none;
    border-radius: 4px;
    font-weight: 600;
    cursor: pointer;
}

.quiz-btn:hover {
    background: #89b4fa;
}

.quiz-score {
    margin-top: 16px;
    padding: 14px 20px;
    background: var(--bg-secondary);
    border: 1px solid var(--border-color);
    border-radius: 6px;
    text-align: center;
    font-size: 16px;
    font-weight: 600;
}

.quiz-score.perfect {
    color: var(--accent-green);
    border-color: var(--accent-green);
}

.quiz-score.good {
    color: var(--accent-blue);
    border-color: var(--accent-blue);
}

.quiz-score.needs-work {
    color: var(--accent-yellow);
    border-color: var(--accent-yellow);
}

.quiz-back-btn {
    display: inline-block;
    margin-bottom: 16px;
    padding: 6px 14px;
    background: var(--bg-tertiary);
    color: var(--text-secondary);
    border: 1px solid var(--border-color);
    border-radius: 4px;
    cursor: pointer;
    font-size: 13px;
}

.quiz-back-btn:hover {
    background: var(--bg-secondary);
    color: var(--text-primary);
}

/* ============================================================
   ADVANCED MODE
   ============================================================ */

body:not(.advanced-mode) .adv { display: none !important; }

/* ---- MODE TOGGLE SWITCH ---- */
.mode-toggle {
    display: flex;
    align-items: center;
    gap: 6px;
    margin-left: 12px;
}

.mode-label {
    font-size: 11px;
    color: var(--text-muted);
    user-select: none;
}

.switch {
    position: relative;
    display: inline-block;
    width: 36px;
    height: 20px;
}

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

.switch .slider {
    position: absolute;
    cursor: pointer;
    inset: 0;
    background: var(--bg-tertiary);
    border: 1px solid var(--border-color);
    border-radius: 20px;
    transition: 0.2s;
}

.switch .slider::before {
    content: '';
    position: absolute;
    height: 14px;
    width: 14px;
    left: 2px;
    bottom: 2px;
    background: var(--text-muted);
    border-radius: 50%;
    transition: 0.2s;
}

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

.switch input:checked + .slider::before {
    transform: translateX(16px);
    background: #1a1b26;
}

/* ---- BREAKPOINTS ---- */
.advanced-mode #line-numbers div {
    cursor: pointer;
    position: relative;
    padding-left: 4px;
}

#line-numbers div.breakpoint::before {
    content: '';
    position: absolute;
    left: 1px;
    top: 50%;
    transform: translateY(-50%);
    width: 8px;
    height: 8px;
    border-radius: 50%;
    background: var(--accent-red);
}

#line-numbers div.line-error {
    background: rgba(247, 118, 142, 0.2);
    color: var(--accent-red);
}

/* ---- TRACE LOG ---- */
#trace-panel {
    grid-row: auto;
    grid-column: 1 / -1;
    background: var(--bg-primary);
    max-height: 180px;
}

#trace-body {
    max-height: 150px;
    overflow: auto;
    padding: 4px 10px;
}

.trace-table {
    width: 100%;
    border-collapse: collapse;
    font-family: 'Cascadia Code', 'Consolas', monospace;
    font-size: 11px;
}

.trace-table th {
    background: var(--bg-secondary);
    color: var(--text-muted);
    padding: 3px 6px;
    text-align: left;
    position: sticky;
    top: 0;
    font-weight: 600;
    border-bottom: 1px solid var(--border-color);
}

.trace-table td {
    padding: 2px 6px;
    color: var(--text-secondary);
    border-bottom: 1px solid rgba(59, 66, 97, 0.3);
}

.trace-table tr:hover td {
    background: var(--bg-tertiary);
    cursor: pointer;
}

/* ---- SYNTAX HIGHLIGHTING ---- */
#highlight-overlay {
    position: absolute;
    top: 0;
    left: 45px;
    right: 0;
    bottom: 0;
    padding: 10px 12px;
    margin: 0;
    background: transparent;
    color: transparent;
    font-family: 'Cascadia Code', 'Consolas', 'Courier New', monospace;
    font-size: 13px;
    line-height: 1.6;
    tab-size: 4;
    white-space: pre;
    overflow: hidden;
    pointer-events: none;
    border: none;
}

.advanced-mode #code-editor {
    color: transparent;
    caret-color: var(--text-primary);
}

.advanced-mode #code-editor::selection {
    background: rgba(122, 162, 247, 0.3);
}

.hl-mnemonic { color: var(--accent-purple); }
.hl-register { color: var(--accent-cyan); }
.hl-number { color: var(--accent-orange); }
.hl-label { color: var(--accent-yellow); }
.hl-directive { color: var(--accent-blue); }
.hl-comment { color: var(--accent-green); font-style: italic; }
.hl-symbol { color: var(--text-secondary); }
.hl-memory { color: var(--accent-orange); }

/* ---- AUTOCOMPLETE ---- */
.ac-dropdown {
    position: absolute;
    z-index: 100;
    background: var(--bg-secondary);
    border: 1px solid var(--border-color);
    border-radius: 4px;
    box-shadow: 0 4px 12px rgba(0,0,0,0.4);
    max-height: 200px;
    overflow-y: auto;
    min-width: 140px;
}

.ac-item {
    padding: 4px 10px;
    font-family: 'Cascadia Code', 'Consolas', monospace;
    font-size: 12px;
    color: var(--text-secondary);
    cursor: pointer;
}

.ac-item:hover, .ac-item.active {
    background: var(--accent-blue);
    color: #1a1b26;
}

.ac-tag {
    font-size: 9px;
    padding: 1px 4px;
    border-radius: 2px;
    margin-right: 4px;
}

.ac-tag.mn { background: var(--accent-purple); color: #1a1b26; }
.ac-tag.rg { background: var(--accent-cyan); color: #1a1b26; }

/* ---- REGISTER/MEMORY EDIT ---- */
.reg-edit-input, .mem-edit-input {
    width: 44px !important;
    padding: 0 3px !important;
    font-size: 12px !important;
    height: 18px;
}

.mem-edit-input {
    width: 24px !important;
}

/* ---- FLAG EXPLANATION ---- */
.flag-explanation {
    padding: 4px 10px;
    font-size: 11px;
    color: var(--text-muted);
    font-style: italic;
    min-height: 18px;
}

/* ---- CYCLE COUNTER ---- */
.cycle-counter {
    font-family: 'Cascadia Code', 'Consolas', monospace;
    font-size: 10px;
    color: var(--text-muted);
    margin-left: auto;
}

/* ---- 7-SEGMENT DISPLAY ---- */
.seven-seg-display {
    position: relative;
    width: 60px;
    height: 100px;
    margin: 8px auto;
}

.seg {
    position: absolute;
    background: var(--bg-tertiary);
    border-radius: 2px;
    transition: background 0.15s;
}

.seg.seg-on {
    background: var(--accent-red);
    box-shadow: 0 0 8px var(--accent-red);
}

.seg.seg-h {
    width: 36px;
    height: 6px;
    left: 12px;
    top: 2px;
}

.seg.seg-mid { top: 47px; }
.seg.seg-bot { top: 92px; }

.seg.seg-v {
    width: 6px;
    height: 38px;
}

.seg.seg-tl { left: 6px; top: 8px; }
.seg.seg-tr { left: 48px; top: 8px; }
.seg.seg-bl { left: 6px; top: 53px; }
.seg.seg-br { left: 48px; top: 53px; }

.sevenseg-val {
    text-align: center;
    font-family: 'Cascadia Code', 'Consolas', monospace;
    font-size: 12px;
    color: var(--text-muted);
}

/* ---- PIXEL DISPLAY ---- */
.pixel-grid {
    display: grid;
    grid-template-columns: repeat(32, 6px);
    grid-template-rows: repeat(32, 6px);
    gap: 0;
    justify-content: center;
}

.pixel {
    width: 6px;
    height: 6px;
    background: #0f0f23;
}

/* ---- KEYBOARD PANEL ---- */
#keyboard-body {
    padding: 8px 10px;
}

#keyboard-input {
    margin-bottom: 6px;
}

.keybuf-label {
    font-size: 11px;
    color: var(--text-muted);
    font-family: 'Cascadia Code', 'Consolas', monospace;
    word-break: break-all;
}

/* ---- CONVERTER ---- */
.converter-body {
    padding: 6px 10px !important;
}

.conv-row {
    display: flex;
    align-items: center;
    gap: 6px;
    margin-bottom: 4px;
    font-size: 12px;
}

.conv-row label {
    width: 30px;
    color: var(--text-muted);
    font-size: 11px;
}

.conv-input {
    flex: 1;
    width: auto !important;
}

.conv-bin {
    font-size: 11px !important;
}

/* ---- CHALLENGES ---- */
.challenge-card {
    background: var(--bg-secondary);
    border: 1px solid var(--border-color);
    border-radius: 4px;
    padding: 8px 12px;
    margin-bottom: 6px;
    cursor: pointer;
    transition: border-color 0.15s;
}

.challenge-card:hover {
    border-color: var(--accent-blue);
}

.challenge-title {
    font-weight: 600;
    font-size: 12px;
    color: var(--accent-blue);
}

.challenge-desc {
    font-size: 11px;
    color: var(--text-muted);
}

.challenge-success {
    color: var(--accent-green);
    font-weight: 600;
    margin-bottom: 6px;
}

.challenge-fail {
    color: var(--accent-red);
    font-weight: 600;
    margin-bottom: 6px;
}

.check-row {
    font-size: 12px;
    margin: 3px 0;
    color: var(--text-secondary);
}

.check-pass {
    color: var(--accent-green);
    font-weight: 600;
    font-size: 11px;
}

.check-fail {
    color: var(--accent-red);
    font-weight: 600;
    font-size: 11px;
}

/* ---- ADVANCED TOOLBAR BUTTONS ---- */
#btn-step-back {
    background: var(--accent-orange);
    color: #1a1b26;
    border-color: var(--accent-orange);
}

#btn-step-back:hover:not(:disabled) {
    background: #ffb07c;
    border-color: #ffb07c;
}

#btn-run-bp {
    background: var(--accent-cyan);
    color: #1a1b26;
    border-color: var(--accent-cyan);
}

#btn-run-bp:hover:not(:disabled) {
    background: #a4e0ff;
    border-color: #a4e0ff;
}

#btn-save, #btn-open, #btn-download {
    font-size: 12px;
    padding: 4px 10px;
}

#btn-load {
    font-size: 12px;
    padding: 3px 6px;
    max-width: 130px;
}

/* ---- GRID ADJUSTMENT FOR TRACE PANEL ---- */
.advanced-mode #app {
    grid-template-rows: 1fr auto auto auto;
}

/* ============================================================
   RESPONSIVE / MOBILE SUPPORT
   ============================================================ */

/* ---- TABLET (<=1024px) ---- */
@media (max-width: 1024px) {
    #app {
        grid-template-columns: 1fr 280px;
    }

    .toolbar-right label[for="sample-select"] {
        display: none;
    }

    #btn-save, #btn-open, #btn-download, #btn-load {
        font-size: 11px;
        padding: 4px 6px;
    }

    .speed-control label {
        display: none;
    }

    #speed-slider {
        width: 60px;
    }
}

/* ---- SMALL TABLET / LARGE PHONE (<=768px) ---- */
@media (max-width: 768px) {
    html, body {
        overflow: auto;
        height: auto;
    }

    #toolbar {
        flex-wrap: wrap;
        height: auto;
        padding: 8px 10px;
        gap: 8px;
    }

    .toolbar-left {
        width: 100%;
        text-align: center;
    }

    .toolbar-center {
        flex-wrap: wrap;
        justify-content: center;
        gap: 6px;
    }

    .toolbar-right {
        flex-wrap: wrap;
        justify-content: center;
        gap: 6px;
        width: 100%;
    }

    .mode-toggle {
        margin-left: 0;
    }

    #app {
        display: flex;
        flex-direction: column;
        height: auto;
        min-height: calc(100vh - 120px);
    }

    #editor-panel {
        min-height: 300px;
        max-height: 50vh;
    }

    #right-panels {
        overflow-y: visible;
        max-height: none;
    }

    #memory-panel {
        max-height: 250px;
    }

    #console-panel {
        max-height: 200px;
    }

    #console-body {
        max-height: 160px;
    }

    #trace-panel {
        max-height: 200px;
    }

    .help-modal {
        width: 96vw;
        height: 92vh;
    }

    .help-modal-content {
        flex-direction: column;
    }

    .help-sidebar {
        width: 100%;
        max-height: 140px;
        border-right: none;
        border-bottom: 1px solid var(--border-color);
        display: flex;
        flex-wrap: wrap;
        padding: 6px;
        gap: 4px;
    }

    .help-sidebar-item {
        padding: 6px 10px;
        font-size: 12px;
        border-left: none;
        border-radius: 4px;
        white-space: nowrap;
    }

    .help-sidebar-item.active {
        border-left: none;
        background: var(--accent-blue);
        color: #1a1b26;
    }

    .help-sidebar-label {
        display: none;
    }

    .help-sidebar-divider {
        display: none;
    }

    .help-body {
        padding: 16px;
    }

    .help-body .help-table {
        font-size: 11px;
        display: block;
        overflow-x: auto;
    }

    .pixel-grid {
        grid-template-columns: repeat(32, 5px);
        grid-template-rows: repeat(32, 5px);
    }

    .pixel {
        width: 5px;
        height: 5px;
    }

    .memory-controls {
        flex-wrap: wrap;
        gap: 4px;
    }

    #memory-dump {
        font-size: 10px;
    }
}

/* ---- PHONE (<=480px) ---- */
@media (max-width: 480px) {
    html {
        font-size: 13px;
    }

    #toolbar {
        padding: 6px 8px;
        gap: 6px;
    }

    .logo {
        font-size: 16px;
    }

    .logo-sub {
        display: none;
    }

    button {
        padding: 6px 10px;
        font-size: 12px;
    }

    .toolbar-center {
        gap: 4px;
    }

    .speed-control {
        margin-left: 0;
    }

    #speed-slider {
        width: 50px;
    }

    .mode-toggle {
        margin-left: 0;
    }

    .mode-label {
        font-size: 10px;
    }

    .toolbar-right label {
        display: none;
    }

    #sample-select {
        max-width: 120px;
        font-size: 11px;
    }

    #editor-panel {
        min-height: 250px;
        max-height: 45vh;
    }

    #code-editor {
        font-size: 12px;
        padding: 8px;
        tab-size: 2;
    }

    #line-numbers {
        width: 32px;
        font-size: 11px;
    }

    #highlight-overlay {
        left: 33px;
        font-size: 12px;
        padding: 8px;
        tab-size: 2;
    }

    .reg-row {
        font-size: 12px;
        gap: 4px;
    }

    .reg-name {
        width: 20px;
        font-size: 11px;
    }

    .reg-val {
        min-width: 38px;
        font-size: 12px;
        padding: 1px 4px;
    }

    .reg-val.small {
        min-width: 24px;
        font-size: 11px;
    }

    .reg-byte-label {
        font-size: 9px;
        margin-left: 2px;
    }

    .flag {
        padding: 3px 6px;
        min-width: 34px;
    }

    .flag-name {
        font-size: 9px;
    }

    .flag-val {
        font-size: 12px;
    }

    #flags-body {
        gap: 4px;
        padding: 6px 8px;
    }

    .led {
        width: 26px;
        height: 26px;
    }

    .led-row {
        gap: 6px;
    }

    .led-bit {
        font-size: 8px;
    }

    .seven-seg-display {
        width: 48px;
        height: 80px;
    }

    .seg.seg-h {
        width: 28px;
        height: 5px;
        left: 10px;
    }
    .seg.seg-mid { top: 38px; }
    .seg.seg-bot { top: 74px; }
    .seg.seg-v {
        width: 5px;
        height: 30px;
    }
    .seg.seg-tl { left: 5px; top: 7px; }
    .seg.seg-tr { left: 38px; top: 7px; }
    .seg.seg-bl { left: 5px; top: 43px; }
    .seg.seg-br { left: 38px; top: 43px; }

    .pixel-grid {
        grid-template-columns: repeat(32, 4px);
        grid-template-rows: repeat(32, 4px);
    }

    .pixel {
        width: 4px;
        height: 4px;
    }

    #memory-body {
        max-height: 140px;
    }

    #memory-dump {
        font-size: 9px;
    }

    .memory-controls {
        gap: 3px;
        font-size: 10px;
    }

    .memory-controls .hex-input {
        width: 40px;
        font-size: 11px;
    }

    .memory-controls select {
        font-size: 10px;
    }

    .memory-controls button {
        font-size: 10px;
        padding: 2px 6px;
    }

    #console-output {
        font-size: 11px;
    }

    .trace-table {
        font-size: 10px;
    }

    .panel-header {
        padding: 5px 8px;
        font-size: 10px;
    }

    .panel-body {
        padding: 6px 8px;
    }

    .help-modal {
        width: 100vw;
        height: 100vh;
        border-radius: 0;
    }

    .help-modal-header {
        padding: 10px 12px;
    }

    .help-modal-header h2 {
        font-size: 14px;
    }

    .help-body {
        padding: 12px;
        line-height: 1.6;
    }

    .help-body h3 {
        font-size: 17px;
    }

    .help-body h4 {
        font-size: 14px;
    }

    .help-body pre {
        font-size: 11px;
        padding: 8px 10px;
    }

    .help-body code {
        font-size: 11px;
    }

    .io-row {
        font-size: 12px;
    }

    .conv-row {
        font-size: 11px;
    }

    .hex-input {
        font-size: 12px;
    }

    select {
        font-size: 12px;
    }

    .challenge-card {
        padding: 6px 8px;
    }

    .challenge-title {
        font-size: 11px;
    }

    .challenge-desc {
        font-size: 10px;
    }
}

/* ---- SAFE AREA INSETS (notch / home indicator) ---- */
@supports (padding-bottom: env(safe-area-inset-bottom)) {
    #toolbar {
        padding-top: max(8px, env(safe-area-inset-top));
        padding-left: max(10px, env(safe-area-inset-left));
        padding-right: max(10px, env(safe-area-inset-right));
    }

    #console-panel,
    #memory-panel {
        padding-bottom: env(safe-area-inset-bottom);
    }
}

/* ---- TOUCH TARGETS ---- */
@media (pointer: coarse) {
    button {
        min-height: 36px;
        min-width: 36px;
    }

    select {
        min-height: 36px;
    }

    .hex-input {
        min-height: 32px;
    }

    .flag {
        padding: 6px 10px;
    }

    .help-sidebar-item {
        min-height: 36px;
        display: flex;
        align-items: center;
    }

    .quiz-option {
        padding: 8px 10px;
    }

    .challenge-card {
        padding: 10px 12px;
    }

    .ac-item {
        padding: 8px 12px;
    }
}

/* ---- LANDSCAPE PHONE ---- */
@media (max-height: 500px) and (orientation: landscape) {
    #toolbar {
        padding: 4px 8px;
        gap: 4px;
    }

    .toolbar-left {
        width: auto;
    }

    #editor-panel {
        min-height: 200px;
    }

    .help-modal {
        height: 100vh;
    }
}