:root{--bg: #f4f6f8;--panel: #ffffff;--panel-border: #dbe2ea;--text: #13243b;--muted: #55657c;--primary: #1d6fd8;--danger: #bf2f45;--line: #2a3e57;--node: #d7e5f8;--node-active: #8bc8ff;--node-muted: #e8edf4}*{box-sizing:border-box}body{margin:0;background:radial-gradient(circle at 14% 10%,#e8effa 0%,var(--bg) 46%,#edf2f7 100%);color:var(--text);font-family:Avenir Next,Segoe UI,sans-serif}.app-shell{min-height:100vh;max-width:1040px;margin:0 auto;padding:28px 20px 36px}.app-header{margin-bottom:12px;display:flex;align-items:flex-end;justify-content:space-between;gap:14px}.app-kicker{margin:0;letter-spacing:.08em;text-transform:uppercase;color:var(--muted);font-size:12px}.app-title{margin:6px 0 0;font-size:30px}.app-nav{display:flex;gap:8px;flex-wrap:wrap}.app-nav__item{border:1px solid var(--panel-border);background:#e8edf4;color:#163253;border-radius:10px;height:34px;padding:0 12px;font-weight:600;cursor:pointer}.app-nav__item--active{background:var(--primary);color:#fff;border-color:transparent}.page{display:grid;gap:14px}.panel{border:1px solid var(--panel-border);border-radius:16px;background:var(--panel);padding:14px;box-shadow:0 9px 24px #1d28370f}.panel__title{margin:0 0 10px;font-size:16px}.page-title{margin:0;font-size:22px}.page-subtitle{margin:8px 0 0;color:var(--muted)}.controls-row{display:flex;flex-wrap:wrap;gap:10px}.capacity-note{margin:0 0 10px;color:var(--muted);font-weight:600}.input{height:38px;min-width:140px;border-radius:10px;border:1px solid var(--panel-border);padding:0 12px;font-size:14px}.input:focus{outline:2px solid rgba(29,111,216,.35);outline-offset:0}.btn{height:38px;border:0;border-radius:10px;padding:0 14px;font-weight:600;cursor:pointer}.btn:disabled{cursor:not-allowed;opacity:.55}.btn--blocked{opacity:.65}.btn--primary{background:var(--primary);color:#fff}.btn--neutral{background:#e7edf5;color:#13243b}.btn--danger{background:var(--danger);color:#fff}.content-grid{display:grid;grid-template-columns:2fr 1fr;gap:14px}.stage-shell{border-radius:14px;border:1px solid var(--panel-border);overflow:hidden}.stack-wall{stroke:var(--line);stroke-width:4;stroke-linecap:round}.edge-arrow{fill:none;stroke-width:2.5}.edge-arrow--default{stroke:#3f5775}.edge-arrow--active{stroke:#1d6fd8}.edge-arrow--muted{stroke:#91a2b8}.edge-arrow--dashed{stroke-dasharray:6 5}.edge-arrow__head--default{fill:#3f5775}.edge-arrow__head--active{fill:#1d6fd8}.edge-arrow__head--muted{fill:#91a2b8}.queue-slot{fill:transparent;stroke:#7a8ca3;stroke-width:2;stroke-dasharray:6 6}.queue-slot__label{fill:#65788f;font-size:12px;font-weight:600}.linkedlist-slot{fill:#1d6fd814;stroke:#1d6fd8;stroke-width:2;stroke-dasharray:6 6}.linkedlist-sentinel{fill:#f2f6fb;stroke:#7588a1;stroke-width:2;stroke-dasharray:6 5}.linkedlist-sentinel__label{fill:#576c87;font-size:12px;font-weight:700}.node-card{stroke:#21446a;stroke-width:2}.node-card--default{fill:var(--node)}.node-card--active{fill:var(--node-active)}.node-card--muted{fill:var(--node-muted)}.node-card__label{fill:#0f243b;font-size:18px;font-weight:700}.pointer__shape{fill:#243a55}.pointer--warn .pointer__shape{fill:#93453f}.pointer__label{fill:#fff;font-size:12px;font-weight:700}.log-list{list-style:none;margin:0;padding:0;display:grid;gap:8px}.log-current{background:#eef4fc;border:1px solid #d6e4f8;border-radius:10px;padding:10px;font-weight:600}.log-item{background:#f8fafc;border:1px solid #e3e9f1;border-radius:10px;padding:8px 10px;display:flex;align-items:center;justify-content:space-between;color:var(--muted)}.output-preview,.preview-compare{margin-top:12px;padding-top:12px;border-top:1px dashed #d9e2ed}.preview-compare__desc{margin:0 0 8px;color:var(--muted);font-size:13px}.output-preview__title{margin:0 0 8px;font-size:15px}.output-preview__subtitle{margin:0 0 8px;font-size:13px;color:#24415f}.output-preview__empty{margin:0;color:var(--muted)}.output-preview__chips{display:flex;flex-wrap:wrap;gap:8px}.output-chip{display:inline-flex;align-items:center;padding:6px 10px;border-radius:999px;background:#eaf2ff;color:#194271;border:1px solid #c9defa;font-weight:600}.queue-preview-grid{display:grid;grid-template-columns:1fr 1fr;gap:10px}.queue-preview-card{border:1px solid #dfe7f0;border-radius:12px;padding:10px;background:#f9fbfd}.queue-preview-list{list-style:none;margin:0;padding:0;display:grid;gap:8px}.queue-preview-item{display:flex;align-items:center;justify-content:space-between;border:1px solid #d7e5f9;border-radius:10px;padding:7px 9px;background:#eef5ff;color:#163254}.queue-preview-item strong{font-size:14px}.linkedlist-seq-panel{border:1px solid #dfe7f0;border-radius:12px;padding:10px;background:#f9fbfd}.tree-node-dot__body{fill:#d7e5f8;stroke:#21446a;stroke-width:2}.tree-node-dot__label{fill:#0f243b;font-size:11px;font-weight:700}.tree-node-dot--active .tree-node-dot__body{fill:#8bc8ff}.tree-node-dot--found .tree-node-dot__body{fill:#7ddf9f;stroke:#227548}.tree-node-dot--muted .tree-node-dot__body{fill:#e8edf4;stroke:#7a8da7}.tree-node-dot--muted .tree-node-dot__label{fill:#61758f}.rb-node-dot__body{stroke-width:2}.rb-node-dot__label{font-size:10px;font-weight:700}.rb-node-dot--red .rb-node-dot__body{fill:#d94a5e;stroke:#962e3d}.rb-node-dot--black .rb-node-dot__body{fill:#2a3646;stroke:#101926}.rb-node-dot--red .rb-node-dot__label,.rb-node-dot--black .rb-node-dot__label{fill:#fff}.rb-node-dot--active .rb-node-dot__body{stroke:#1d6fd8;stroke-width:3}.rb-node-dot--found .rb-node-dot__body{stroke:#2b9d53;stroke-width:3;filter:drop-shadow(0 0 5px rgba(43,157,83,.35))}.rb-node-dot--muted{opacity:.55}.bst-status-panel{border:1px solid #dfe7f0;border-radius:12px;padding:10px;background:#f9fbfd}.bst-status-panel__text{margin:0;color:#264566;font-weight:600;min-height:20px}.rbt-legend{margin-top:10px;display:flex;flex-wrap:wrap;gap:10px}.rbt-legend__item{display:inline-flex;align-items:center;gap:6px;font-size:12px;color:#2a425f;background:#f3f7fc;border:1px solid #d7e3f2;border-radius:999px;padding:5px 10px}.rbt-legend__dot{width:10px;height:10px;border-radius:50%;display:inline-block}.rbt-legend__dot--red{background:#d94a5e}.rbt-legend__dot--black{background:#2a3646}.rbt-rotate-guide{fill:none;stroke-width:3}.rbt-rotate-guide--left{stroke:#dd8a17}.rbt-rotate-guide--right{stroke:#1f9aa8}.rbt-rotate-guide__head--left{fill:#dd8a17}.rbt-rotate-guide__head--right{fill:#1f9aa8}.rbt-rotate-guide__text{fill:#2b445f;font-size:12px;font-weight:700}@media(max-width:900px){.app-header{align-items:flex-start;flex-direction:column}.content-grid,.queue-preview-grid{grid-template-columns:1fr}}