:root {
    --bg:          #f4f6fb;
    --surface:     #ffffff;
    --surface2:    #eef1f8;
    --border:      #dde2ee;
    --border2:     #c8cfdf;
    --green:       #007a50;
    --green-dim:   #005c3c;
    --green-glow:  rgba(0, 122, 80, 0.08);
    --amber:       #a05c00;
    --amber-bg:    rgba(160, 92, 0, 0.07);
    --amber-glow:  rgba(160, 92, 0, 0.18);
    --blue:        #1a56c4;
    --red:         #c82020;
    --text:        #1a1f36;
    --text-dim:    #9ba3b8;
    --text-mid:    #5a6478;
    --font:        'JetBrains Mono', monospace;
    --radius:      5px;
}

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

body {
    background: var(--bg);
    color: var(--text);
    font-family: var(--font);
    min-height: 100vh;
    padding: 28px 24px;
    max-width: 900px;
    margin: 0 auto;
}

/* ── Header ── */
header {
    display: flex;
    align-items: baseline;
    gap: 10px;
    margin-bottom: 22px;
}

h1 {
    font-size: 12px;
    font-weight: 700;
    letter-spacing: 0.3em;
    text-transform: uppercase;
    color: var(--green);
}

.version-tag {
    font-size: 10px;
    color: var(--text-dim);
    letter-spacing: 0.1em;
}

/* ── Panel ── */
.panel {
    background: var(--surface);
    border: 1px solid var(--border);
    border-radius: var(--radius);
    margin-bottom: 10px;
    overflow: hidden;
    box-shadow: 0 1px 4px rgba(0, 0, 0, 0.04);
}

.panel-label {
    padding: 5px 12px;
    font-size: 9px;
    letter-spacing: 0.25em;
    text-transform: uppercase;
    color: var(--text-dim);
    background: var(--surface2);
    border-bottom: 1px solid var(--border);
    user-select: none;
}

/* ── Source textarea ── */
textarea {
    display: block;
    width: 100%;
    background: transparent;
    border: none;
    color: var(--green);
    font-family: var(--font);
    font-size: 14px;
    padding: 12px;
    resize: vertical;
    min-height: 76px;
    outline: none;
    caret-color: var(--green);
    line-height: 1.6;
}

textarea::selection {
    background: var(--green-glow);
}

/* ── Controls ── */
.controls {
    display: flex;
    align-items: center;
    gap: 6px;
    padding: 10px 12px;
    flex-wrap: wrap;
    background: var(--surface);
    border: 1px solid var(--border);
    border-radius: var(--radius);
    margin-bottom: 10px;
    box-shadow: 0 1px 4px rgba(0, 0, 0, 0.04);
}

.btn-group {
    display: flex;
    gap: 4px;
}

button {
    background: var(--surface2);
    border: 1px solid var(--border2);
    color: var(--text-mid);
    font-family: var(--font);
    font-size: 10px;
    font-weight: 700;
    letter-spacing: 0.12em;
    text-transform: uppercase;
    padding: 6px 12px;
    cursor: pointer;
    border-radius: var(--radius);
    transition: border-color 0.12s, color 0.12s, background 0.12s, box-shadow 0.12s;
    white-space: nowrap;
}

button:hover:not(:disabled) {
    border-color: var(--green-dim);
    color: var(--green);
    background: var(--green-glow);
}

button.active-run {
    border-color: var(--green);
    color: var(--green);
    background: var(--green-glow);
}

button:disabled {
    opacity: 0.3;
    cursor: default;
}

.divider {
    width: 1px;
    height: 20px;
    background: var(--border2);
    margin: 0 4px;
}

/* Speed control */
.speed-group {
    display: flex;
    align-items: center;
    gap: 8px;
    margin-left: auto;
}

.speed-label-text {
    font-size: 9px;
    letter-spacing: 0.2em;
    text-transform: uppercase;
    color: var(--text-dim);
}

.speed-presets {
    display: flex;
    gap: 3px;
}

.speed-btn {
    padding: 4px 8px;
    font-size: 9px;
    letter-spacing: 0.05em;
}

.speed-btn.selected {
    border-color: var(--amber);
    color: var(--amber);
    background: var(--amber-bg);
}

/* ── Code view ── */
#codeView {
    padding: 12px;
    font-size: 13px;
    line-height: 2;
    word-break: break-all;
    min-height: 48px;
    overflow-x: auto;
}

.code-char {
    display: inline-block;
    border-radius: 2px;
}

.code-char.bf-op {
    color: var(--blue);
}

.code-char.bf-loop {
    color: #7c3aed;
}

.code-char.bf-io {
    color: #c2410c;
}

.code-active {
    background: var(--amber);
    color: #fff !important;
    box-shadow: 0 0 6px var(--amber-glow);
}

/* ── Status bar ── */
.statusbar {
    display: flex;
    align-items: center;
    padding: 5px 12px;
    font-size: 9px;
    color: var(--text-dim);
    border-top: 1px solid var(--border);
    letter-spacing: 0.08em;
    flex-wrap: wrap;
    gap: 16px;
}

.status-item {
    display: flex;
    align-items: center;
    gap: 5px;
}

.status-item b {
    color: var(--text);
    font-weight: 400;
    font-size: 10px;
}

#statusIndicator {
    display: flex;
    align-items: center;
    gap: 6px;
}

.dot {
    width: 5px;
    height: 5px;
    border-radius: 50%;
    background: var(--text-dim);
    flex-shrink: 0;
}

.dot.idle    { background: var(--text-dim); }
.dot.running { background: var(--green); animation: blink 0.9s ease-in-out infinite; }
.dot.paused  { background: var(--amber); }
.dot.done    { background: var(--blue); }

@keyframes blink {
    0%, 100% { opacity: 1; }
    50%       { opacity: 0.3; }
}

/* ── Memory ── */
#memory-container {
    overflow-x: auto;
    padding: 10px 12px;
}

#memory {
    display: flex;
    gap: 3px;
}

.cell {
    flex-shrink: 0;
    width: 38px;
    height: 38px;
    border: 1px solid var(--border);
    border-radius: 3px;
    text-align: center;
    line-height: 38px;
    font-size: 10px;
    color: var(--text-dim);
    transition: background 0.1s, border-color 0.1s, color 0.1s;
}

.cell.nonzero {
    color: var(--text);
    border-color: var(--border2);
}

.cell.active {
    background: var(--amber-bg);
    border-color: var(--amber);
    color: var(--amber);
}

/* ── Output ── */
#output-box {
    padding: 12px;
    min-height: 72px;
    max-height: 180px;
    overflow-y: auto;
    color: var(--green);
    white-space: pre-wrap;
    font-size: 14px;
    line-height: 1.7;
}

#output-box:empty::before {
    content: '—';
    color: var(--text-dim);
}

/* Scrollbar */
::-webkit-scrollbar       { width: 5px; height: 5px; }
::-webkit-scrollbar-track { background: transparent; }
::-webkit-scrollbar-thumb { background: var(--border2); border-radius: 3px; }

.info {
    margin: 30px 0;
    padding: 20px;
}
h4 {margin-bottom: 10px;}

footer {margin: 30px 0;}
footer a {
    text-decoration: none;
    color: #000;
}
footer a:hover {color: #777;}