/* ── Layout ──────────────────────────────────────────────────────────── */
.ll-container {
    margin: 0 auto;
    padding: 1rem 0 3rem;
}
.ll-container h1 {
    margin-bottom: 0.5rem;
}
.ll-desc {
    color: var(--text-secondary);
    margin-bottom: 1rem;
}

/* ── Tabs ────────────────────────────────────────────────────────────── */
.ll-tabs {
    display: flex;
    gap: 0;
    margin-bottom: 1rem;
    border-bottom: 2px solid var(--border-primary);
}
.ll-tab {
    padding: 0.45rem 1.2rem;
    border: none;
    border-bottom: 2px solid transparent;
    margin-bottom: -2px;
    background: none;
    font-size: 0.9rem;
    font-weight: 600;
    color: var(--text-secondary);
    cursor: pointer;
    border-radius: 4px 4px 0 0;
    transition:
        color 0.15s,
        border-color 0.15s;
}
.ll-tab:hover {
    color: var(--text-primary);
}
.ll-tab-active {
    color: var(--text-primary);
    border-bottom-color: #2980b9;
}

/* ── Workspace ───────────────────────────────────────────────────────── */
.ll-workspace {
    display: grid;
    grid-template-columns: 360px 1fr 300px;
    gap: 1.25rem;
    align-items: start;
}
@media (max-width: 1100px) {
    .ll-workspace {
        grid-template-columns: 360px 1fr;
    }
    .ll-output-panel {
        grid-column: 1 / -1;
    }
}
@media (max-width: 700px) {
    .ll-workspace {
        grid-template-columns: 1fr;
    }
}

/* Mode-based quick ref visibility */
#ll-workspace[data-mode="singly"] .ll-ref-doubly {
    display: none;
}
#ll-workspace[data-mode="doubly"] .ll-ref-singly {
    display: none;
}

/* ── Panels ──────────────────────────────────────────────────────────── */
.ll-panel {
    border: 1px solid var(--border-primary);
    border-radius: 6px;
    padding: 1rem;
    background: var(--bg-secondary);
}
.ll-panel h2 {
    font-size: 0.85rem;
    font-weight: 700;
    margin-bottom: 0.75rem;
    color: var(--text-secondary);
    text-transform: uppercase;
    letter-spacing: 0.06em;
}

/* ── Textarea ────────────────────────────────────────────────────────── */
#ll-input {
    width: 100%;
    font-family: "Courier New", Courier, monospace;
    font-size: 0.9rem;
    padding: 0.6rem 0.75rem;
    border: 1px solid var(--border-primary);
    border-radius: 4px;
    resize: vertical;
    background: var(--bg-primary);
    color: var(--text-primary);
    line-height: 1.5;
}
#ll-input:focus {
    outline: 2px solid var(--text-link);
    outline-offset: 1px;
}

/* ── Buttons ─────────────────────────────────────────────────────────── */
.ll-btn-row {
    display: flex;
    gap: 0.5rem;
    margin-top: 0.6rem;
    flex-wrap: wrap;
}
.ll-btn {
    padding: 0.45rem 1rem;
    border: none;
    border-radius: 4px;
    font-size: 0.9rem;
    font-weight: 600;
    cursor: pointer;
}
.ll-btn kbd {
    font-size: 0.75em;
    opacity: 0.7;
    font-weight: normal;
}
.ll-btn-primary {
    background: #2980b9;
    color: #fff;
}
.ll-btn-primary:hover {
    background: #1a6a9a;
}
.ll-btn-secondary {
    background: var(--bg-tertiary);
    color: var(--text-primary);
    border: 1px solid var(--border-primary);
}
.ll-btn-secondary:hover {
    background: var(--border-primary);
}
.ll-btn-danger {
    background: #c0392b;
    color: #fff;
}
.ll-btn-danger:hover {
    background: #a93226;
}

/* ── Templates ───────────────────────────────────────────────────────── */
.ll-templates-section {
    margin-top: 1rem;
}
.ll-template-grid {
    display: flex;
    flex-wrap: wrap;
    gap: 0.4rem;
    margin-top: 0.5rem;
}
.ll-template-btn {
    padding: 0.3rem 0.75rem;
    border: 1px solid var(--border-primary);
    border-radius: 4px;
    background: var(--bg-primary);
    color: var(--text-primary);
    font-size: 0.82rem;
    cursor: pointer;
    white-space: nowrap;
    transition:
        background 0.12s,
        border-color 0.12s;
}
.ll-template-btn:hover {
    background: #2980b9;
    border-color: #2980b9;
    color: #fff;
}

/* ── Quick Reference ─────────────────────────────────────────────────── */
.ll-ref {
    margin-top: 1rem;
    font-size: 0.85rem;
}
.ll-ref summary {
    cursor: pointer;
    color: var(--text-secondary);
    user-select: none;
    padding: 0.25rem 0;
}
.ll-ref table {
    width: 100%;
    border-collapse: collapse;
    margin-top: 0.5rem;
}
.ll-ref td {
    padding: 0.2rem 0.4rem;
    vertical-align: top;
}
.ll-ref td:first-child {
    white-space: nowrap;
}
.ll-ref td:last-child {
    color: var(--text-secondary);
    padding-left: 0.75rem;
}
.ll-ref code {
    background: var(--bg-primary);
    border: 1px solid var(--border-primary);
    border-radius: 3px;
    padding: 0.1rem 0.3rem;
    font-size: 0.82rem;
}

/* ── Diagram ─────────────────────────────────────────────────────────── */
.ll-diagram-scroll {
    overflow-x: auto;
    padding-bottom: 0.5rem;
    min-height: 140px;
}
#ll-diagram {
    display: block;
}
.ll-stats {
    margin-top: 0.5rem;
    font-size: 0.85rem;
    color: var(--text-secondary);
}

/* ── SVG element classes ─────────────────────────────────────────────── */
:root {
    --ll-node-fill: #dbeeff;
    --ll-node-stroke: #2980b9;
    --ll-arrow: #555;
    --ll-flash-color: #f5c518;
}
@media (prefers-color-scheme: dark) {
    :root {
        --ll-node-fill: #1a3a5c;
        --ll-node-stroke: #5dade2;
        --ll-arrow: #aaa;
        --ll-flash-color: #d4a017;
    }
}

.ll-node-rect {
    fill: var(--ll-node-fill);
    stroke: var(--ll-node-stroke);
    stroke-width: 2;
}
.ll-divider {
    stroke: var(--ll-node-stroke);
    stroke-width: 1;
    opacity: 0.4;
}
.ll-val-text {
    font-family: "Courier New", Courier, monospace;
    font-size: 16px;
    font-weight: bold;
    fill: var(--text-primary);
}
.ll-next-label {
    font-size: 9px;
    fill: var(--text-secondary);
    font-family: system-ui, sans-serif;
}
.ll-ptr-dot {
    fill: var(--ll-node-stroke);
}
.ll-null-ptr {
    fill: var(--text-secondary);
    font-size: 15px;
    font-family: system-ui, sans-serif;
}
.ll-arrow {
    stroke: var(--ll-arrow);
    stroke-width: 2;
    fill: none;
}
.ll-arrowhead {
    fill: var(--ll-arrow);
}
.ll-null-rect {
    fill: var(--bg-primary);
    stroke: var(--text-secondary);
    stroke-width: 1.5;
    stroke-dasharray: 4 3;
}
.ll-null-text {
    font-family: "Courier New", Courier, monospace;
    font-size: 12px;
    font-style: italic;
    fill: var(--text-secondary);
}
.ll-head-label {
    font-family: system-ui, sans-serif;
    font-size: 12px;
    font-weight: bold;
    fill: var(--text-primary);
}
.ll-null-label {
    font-family: system-ui, sans-serif;
    font-size: 12px;
    font-style: italic;
    fill: var(--text-secondary);
}
.ll-index-label {
    font-family: system-ui, sans-serif;
    font-size: 10px;
    fill: var(--text-secondary);
}

/* ── Node group interactivity ────────────────────────────────────────── */
.ll-node-group {
    cursor: grab;
}
.ll-node-group:hover .ll-node-rect {
    stroke-width: 3;
    filter: brightness(1.08);
}

/* ── Node icons (edit / delete) ──────────────────────────────────────── */
.ll-node-icon {
    opacity: 0;
    cursor: pointer;
    transition: opacity 0.15s;
}
.ll-node-group:hover .ll-node-icon {
    opacity: 1;
}
.ll-icon-circle {
    fill: var(--bg-secondary);
    stroke: var(--ll-node-stroke);
    stroke-width: 1.5;
}
.ll-node-icon:hover .ll-icon-circle {
    fill: var(--ll-node-stroke);
}
.ll-icon-text {
    font-size: 10px;
    font-family: system-ui, sans-serif;
    fill: var(--text-primary);
    text-anchor: middle;
    dominant-baseline: middle;
    pointer-events: none;
    user-select: none;
}
.ll-node-icon:hover .ll-icon-text {
    fill: #fff;
}

/* ── Node flash animation (new/changed nodes) ────────────────────────── */
@keyframes ll-flash {
    0%   { fill: var(--ll-flash-color); }
    60%  { fill: var(--ll-flash-color); }
    100% { fill: var(--ll-node-fill); }
}
.ll-node-new .ll-node-rect {
    animation: ll-flash 0.7s ease-out forwards;
}

/* ── Output panel ────────────────────────────────────────────────────── */
.ll-output-panel {
    display: flex;
    flex-direction: column;
}
.ll-history {
    font-family: "Courier New", Courier, monospace;
    font-size: 0.82rem;
    flex: 1;
    max-height: 500px;
    overflow-y: auto;
    padding: 0.5rem 0.75rem;
    background: var(--bg-primary);
    border: 1px solid var(--border-primary);
    border-radius: 4px;
}
.ll-entry {
    margin-bottom: 0.5rem;
}
.ll-code-line {
    color: var(--text-primary);
}
.ll-log-line {
    color: var(--text-secondary);
    padding-left: 1rem;
}
.ll-op-line {
    color: #2980b9;
    padding-left: 1rem;
    font-style: italic;
}
.ll-ret-line {
    color: #27ae60;
    padding-left: 1rem;
}
.ll-err-line {
    color: #e74c3c;
    padding-left: 1rem;
}
@media (prefers-color-scheme: dark) {
    .ll-ret-line {
        color: #2ecc71;
    }
    .ll-op-line {
        color: #5dade2;
    }
}