:root {
    --ink: #171916;
    --ink-2: #1d201c;
    --ink-3: #252922;
    --paper: #eee9da;
    --paper-soft: #c8c2b2;
    --paper-dim: #8e8b80;
    --line: rgba(238, 233, 218, 0.24);
    --line-strong: rgba(238, 233, 218, 0.5);
    --accent: #c9876e;
    --accent-bright: #e2a087;
    --moss: #8e9a78;
    --blue: #7f9ea6;
    --danger: #d9776d;
    --sans: "Noto Sans KR", sans-serif;
    --serif: "Gowun Batang", serif;
    --mono: "DM Mono", monospace;
    --panel-width: 304px;
    --right-width: 326px;
}

* { box-sizing: border-box; }

html, body { min-height: 100%; }

body {
    margin: 0;
    background: var(--ink);
    color: var(--paper);
    font-family: var(--sans);
    font-size: 14px;
    -webkit-font-smoothing: antialiased;
}

button, input { font: inherit; }

button { color: inherit; }

button:focus-visible,
input:focus-visible,
[tabindex]:focus-visible {
    outline: 2px solid var(--accent-bright);
    outline-offset: 3px;
}

.app-shell { min-height: 100vh; }

.topbar {
    height: 82px;
    display: grid;
    grid-template-columns: minmax(280px, 1fr) minmax(260px, 0.72fr) minmax(410px, 1fr);
    align-items: center;
    gap: 24px;
    padding: 0 22px;
    border-bottom: 1px solid var(--line);
    background: rgba(23, 25, 22, 0.96);
    position: sticky;
    top: 0;
    z-index: 20;
    backdrop-filter: blur(18px);
}

.brand-block { display: flex; align-items: center; gap: 14px; min-width: 0; }
.back-link {
    width: 38px;
    height: 38px;
    border: 1px solid var(--line);
    display: grid;
    place-items: center;
    color: var(--paper);
    text-decoration: none;
    transition: 180ms ease;
}
.back-link:hover { border-color: var(--paper-soft); background: rgba(255,255,255,0.04); transform: translateX(-2px); }
.brand-kicker { color: var(--paper-dim); font: 10px/1 var(--mono); letter-spacing: 0.12em; }
.brand-title-row { display: flex; gap: 9px; align-items: center; margin-top: 5px; }
.brand-title-row h1 { margin: 0; font: 500 19px/1 var(--mono); letter-spacing: -0.035em; }
.beta-badge { padding: 3px 6px; border: 1px solid var(--accent); color: var(--accent-bright); font: 9px/1 var(--mono); }

.project-meta { display: grid; gap: 5px; justify-self: center; width: min(100%, 330px); }
.project-meta label { color: var(--paper-dim); font: 9px/1 var(--mono); letter-spacing: 0.14em; }
.project-meta input {
    width: 100%;
    border: 0;
    border-bottom: 1px solid var(--line);
    background: transparent;
    color: var(--paper);
    padding: 4px 0 7px;
    font: 500 13px/1.2 var(--sans);
}

.top-actions { display: flex; justify-content: flex-end; gap: 8px; }
.text-button, .primary-button, .tool-button, .icon-button {
    border: 1px solid var(--line);
    background: transparent;
    cursor: pointer;
    transition: 160ms ease;
}
.text-button { padding: 10px 12px; color: var(--paper-soft); font-size: 12px; }
.text-button:hover, .tool-button:hover { border-color: var(--paper-soft); color: var(--paper); background: rgba(255,255,255,0.035); }
.primary-button { display: flex; gap: 20px; align-items: center; padding: 10px 14px; border-color: var(--paper); background: var(--paper); color: var(--ink); font-size: 12px; font-weight: 700; }
.primary-button:hover { background: var(--accent-bright); border-color: var(--accent-bright); }

.workspace {
    min-height: calc(100vh - 82px);
    display: grid;
    grid-template-columns: var(--panel-width) minmax(560px, 1fr) var(--right-width);
}

.panel { min-width: 0; padding: 24px 20px 30px; background: var(--ink-2); }
.panel-left { border-right: 1px solid var(--line); }
.panel-right { border-left: 1px solid var(--line); }
.panel-heading { display: flex; align-items: center; justify-content: space-between; gap: 12px; }
.panel-heading > div { display: flex; align-items: baseline; gap: 10px; }
.section-index { color: var(--accent-bright); font: 11px/1 var(--mono); }
.panel-heading h2 { margin: 0; font: 600 16px/1.2 var(--sans); letter-spacing: -0.02em; }
.panel-intro { margin: 13px 0 18px; color: var(--paper-dim); font-size: 11px; line-height: 1.7; word-break: keep-all; }
.icon-button { width: 32px; height: 32px; color: var(--paper-soft); font-size: 18px; }
.icon-button:hover { color: var(--paper); border-color: var(--paper-soft); transform: rotate(-18deg); }

.preset-row { display: grid; grid-template-columns: repeat(3, 1fr); padding: 3px; background: var(--ink); border: 1px solid var(--line); }
.preset { border: 0; background: transparent; padding: 8px 4px; color: var(--paper-dim); font-size: 11px; cursor: pointer; }
.preset.active { background: var(--paper); color: var(--ink); font-weight: 700; }

.program-list { margin-top: 15px; border-top: 1px solid var(--line); }
.program-row { display: grid; grid-template-columns: 9px 1fr auto; align-items: center; gap: 10px; min-height: 45px; border-bottom: 1px solid var(--line); }
.program-swatch { width: 7px; height: 7px; border-radius: 50%; background: var(--paper-soft); }
.program-swatch.public { background: var(--paper); }
.program-swatch.private { background: var(--blue); }
.program-swatch.service { background: var(--moss); }
.program-swatch.outdoor { background: var(--accent); }
.program-name { display: grid; gap: 2px; min-width: 0; }
.program-name b { font-size: 12px; font-weight: 500; }
.program-name small { color: var(--paper-dim); font: 9px/1 var(--mono); text-transform: uppercase; }
.counter { display: flex; align-items: center; border: 1px solid var(--line); }
.counter button { width: 25px; height: 25px; border: 0; background: transparent; color: var(--paper-dim); cursor: pointer; }
.counter button:hover { background: rgba(255,255,255,0.06); color: var(--paper); }
.counter output { min-width: 22px; text-align: center; font: 11px/1 var(--mono); }

.control-section { margin-top: 20px; }
.control-label-row { display: flex; align-items: center; justify-content: space-between; }
.control-label-row label { font-size: 12px; font-weight: 600; }
.control-label-row output { color: var(--accent-bright); font: 10px/1 var(--mono); }
input[type="range"] { accent-color: var(--accent); }
.control-section input[type="range"] { width: 100%; margin: 14px 0 6px; }
.range-legend { display: flex; justify-content: space-between; color: var(--paper-dim); font: 9px/1 var(--mono); }

.toggle-stack { margin-top: 18px; border-top: 1px solid var(--line); }
.switch-row { min-height: 61px; border-bottom: 1px solid var(--line); display: grid; grid-template-columns: 1fr auto; align-items: center; gap: 12px; cursor: pointer; position: relative; }
.switch-row > span { display: grid; gap: 4px; }
.switch-row b { font-size: 11px; font-weight: 600; }
.switch-row small { color: var(--paper-dim); font-size: 9px; line-height: 1.45; word-break: keep-all; }
.switch-row input { position: absolute; opacity: 0; }
.switch-row i { width: 30px; height: 16px; border-radius: 20px; background: #4b4d47; position: relative; transition: 160ms ease; }
.switch-row i::after { content: ""; position: absolute; width: 10px; height: 10px; border-radius: 50%; background: var(--paper); left: 3px; top: 3px; transition: 160ms ease; }
.switch-row input:checked + i { background: var(--accent); }
.switch-row input:checked + i::after { transform: translateX(14px); background: var(--ink); }

.generate-button { width: 100%; margin-top: 18px; display: flex; justify-content: space-between; align-items: center; border: 1px solid var(--accent); background: var(--accent); color: var(--ink); padding: 12px 14px; font-size: 12px; font-weight: 700; cursor: pointer; }
.generate-button:hover { background: var(--accent-bright); border-color: var(--accent-bright); }
.generate-button:active { transform: translateY(1px); }

.manual-transition { margin-top: 22px; }
.mini-heading { display: flex; align-items: baseline; justify-content: space-between; gap: 10px; }
.mini-heading h3 { margin: 0; font-size: 11px; }
.mini-heading > span, .mini-heading button { color: var(--paper-dim); font: 9px/1 var(--mono); }
.mini-heading button { border: 0; background: transparent; padding: 0; cursor: pointer; }
.mini-heading button:hover { color: var(--accent-bright); }
.transition-palette { margin-top: 10px; display: grid; grid-template-columns: 1fr 1fr; gap: 6px; }
.transition-chip { text-align: left; border: 1px solid var(--line); background: transparent; padding: 8px; color: var(--paper-soft); cursor: pointer; display: grid; gap: 4px; }
.transition-chip:hover { border-color: var(--accent); background: rgba(201,135,110,0.08); }
.transition-chip b { font-size: 10px; }
.transition-chip span { color: var(--paper-dim); font: 8px/1 var(--mono); }

.canvas-column { min-width: 0; display: flex; flex-direction: column; background: var(--ink); }
.canvas-toolbar { min-height: 58px; display: flex; align-items: center; justify-content: space-between; gap: 18px; padding: 0 20px; border-bottom: 1px solid var(--line); }
.view-tabs { display: flex; align-self: stretch; }
.view-tab { border: 0; border-bottom: 2px solid transparent; background: transparent; color: var(--paper-dim); padding: 0 14px; cursor: pointer; font-size: 11px; }
.view-tab.active { color: var(--paper); border-bottom-color: var(--accent); }
.canvas-tools { display: flex; align-items: center; gap: 8px; }
.zoom-control { display: flex; align-items: center; gap: 8px; color: var(--paper-dim); font: 9px/1 var(--mono); }
.zoom-control input { width: 70px; }
.tool-button { padding: 7px 9px; color: var(--paper-dim); font-size: 10px; }

.diagram-frame { flex: 1; min-height: 590px; position: relative; display: flex; flex-direction: column; overflow: hidden; }
.diagram-caption { display: flex; justify-content: space-between; align-items: baseline; padding: 18px 24px 0; }
.diagram-caption p { margin: 0; color: var(--paper-soft); font: italic 13px/1.2 var(--serif); }
.diagram-caption span { color: var(--paper-dim); font: 9px/1 var(--mono); letter-spacing: .08em; }
.svg-scroll { flex: 1; min-height: 480px; overflow: auto; display: grid; align-items: center; }
#topology-svg { width: 100%; min-width: 780px; height: 100%; min-height: 500px; overflow: visible; transition: width 180ms ease; }

.depth-line { stroke: var(--line); stroke-width: 1; }
.depth-tick { stroke: var(--paper-dim); stroke-width: 1; }
.depth-index { fill: var(--paper-soft); font: 400 12px var(--mono); }
.depth-name { fill: var(--paper-dim); font: 400 9px var(--mono); letter-spacing: .08em; }
.edge-path { fill: none; stroke: var(--paper-soft); stroke-width: 1.4; opacity: .82; transition: 160ms ease; }
.edge-path.highlight { stroke: var(--accent-bright); stroke-width: 2.6; opacity: 1; }
.sight-path { fill: none; stroke: var(--accent); stroke-width: 1.2; stroke-dasharray: 7 6; opacity: 0; transition: opacity 180ms ease; }
.show-sight .sight-path { opacity: .66; }
.node { cursor: grab; }
.node:active { cursor: grabbing; }
.node .node-circle { stroke: var(--paper); stroke-width: 1.7; fill: var(--ink); transition: 160ms ease; }
.node.transition .node-circle { fill: var(--accent); stroke: var(--accent-bright); }
.node.root .node-circle { fill: var(--paper); stroke: var(--paper); }
.node.private .node-circle { stroke: var(--blue); }
.node.service .node-circle { stroke: var(--moss); }
.node.outdoor .node-circle { stroke: var(--accent-bright); }
.node.selected .node-circle { stroke-width: 3; filter: drop-shadow(0 0 8px rgba(226,160,135,.4)); }
.node:hover .node-circle { stroke-width: 3; }
.node-code { fill: var(--paper); font: 500 13px var(--mono); text-anchor: middle; dominant-baseline: central; pointer-events: none; }
.node.root .node-code { fill: var(--ink); }
.node-label { fill: var(--paper-soft); font: 500 10px var(--sans); text-anchor: middle; pointer-events: none; }
.node-meta { fill: var(--paper-dim); font: 400 8px var(--mono); text-anchor: middle; pointer-events: none; letter-spacing: .06em; }
.node-halo { fill: none; stroke: var(--accent); stroke-width: 1; stroke-dasharray: 2 5; opacity: 0; }
.node.transition .node-halo { opacity: .5; }

.canvas-footer { min-height: 48px; display: flex; align-items: center; justify-content: space-between; gap: 14px; padding: 9px 22px; border-top: 1px solid var(--line); }
.canvas-footer p { margin: 0; color: var(--paper-dim); font-size: 9px; }
.legend { display: flex; flex-wrap: wrap; gap: 12px; }
.legend span { display: inline-flex; align-items: center; gap: 5px; color: var(--paper-dim); font-size: 9px; }
.legend-node { width: 8px; height: 8px; display: inline-block; border-radius: 50%; border: 1px solid var(--paper); }
.legend-node.root { background: var(--paper); }
.legend-node.transition { background: var(--accent); border-color: var(--accent); }
.legend-line { width: 15px; height: 1px; display: inline-block; background: var(--paper-soft); }
.legend-line.sight { background: repeating-linear-gradient(90deg, var(--accent) 0 3px, transparent 3px 5px); }

.logic-strip { display: grid; grid-template-columns: repeat(4, 1fr); border-top: 1px solid var(--line); min-height: 96px; }
.logic-strip article { padding: 14px 16px; display: grid; align-content: center; gap: 5px; border-right: 1px solid var(--line); }
.logic-strip article:last-child { border-right: 0; }
.logic-strip span { color: var(--paper-dim); font: 8px/1 var(--mono); letter-spacing: .08em; }
.logic-strip strong { font: 400 20px/1.1 var(--mono); }
.logic-strip small { color: var(--paper-dim); font-size: 9px; }
.logic-strip .score-card { background: var(--paper); color: var(--ink); }
.logic-strip .score-card span, .logic-strip .score-card small { color: rgba(23,25,22,.65); }

.selection-card { margin-top: 18px; padding: 15px; border: 1px solid rgba(201,135,110,.55); background: rgba(201,135,110,.05); }
.selection-topline { display: flex; align-items: center; justify-content: space-between; color: var(--accent-bright); font: 9px/1 var(--mono); }
.selection-card > label { display: block; margin-top: 14px; color: var(--paper-dim); font-size: 9px; }
.selection-card > input { width: 100%; margin-top: 3px; border: 0; border-bottom: 1px solid var(--line); padding: 5px 0 8px; background: transparent; color: var(--paper); font-size: 17px; font-weight: 600; }
.selection-card > p { min-height: 50px; margin: 12px 0 0; color: var(--paper-soft); font: 13px/1.7 var(--serif); word-break: keep-all; }
.attribute-grid { display: grid; grid-template-columns: repeat(3, 1fr); margin-top: 13px; border-top: 1px solid var(--line); border-bottom: 1px solid var(--line); }
.attribute-grid div { padding: 10px 4px; display: grid; gap: 5px; border-right: 1px solid var(--line); }
.attribute-grid div:last-child { border-right: 0; }
.attribute-grid span { color: var(--paper-dim); font-size: 8px; }
.attribute-grid b { font: 500 10px/1 var(--mono); }
.selection-actions { display: grid; grid-template-columns: 1.4fr 1fr; gap: 6px; margin-top: 12px; }
.selection-actions button { border: 1px solid var(--line); background: transparent; color: var(--paper-soft); padding: 8px 4px; cursor: pointer; font-size: 9px; }
.selection-actions button:hover { border-color: var(--accent); color: var(--paper); }
.selection-actions button:disabled { opacity: .35; cursor: not-allowed; }

.explanation-section, .recommendation-section { margin-top: 24px; }
.route-list { margin: 13px 0 0; padding: 0; list-style: none; }
.route-list li { position: relative; padding: 0 0 17px 28px; color: var(--paper-soft); font-size: 10px; line-height: 1.55; }
.route-list li::before { content: attr(data-step); position: absolute; left: 0; top: -2px; width: 18px; height: 18px; border: 1px solid var(--line-strong); border-radius: 50%; display: grid; place-items: center; color: var(--paper); font: 8px/1 var(--mono); }
.route-list li:not(:last-child)::after { content: ""; position: absolute; left: 9px; top: 18px; width: 1px; height: calc(100% - 18px); background: var(--line); }
.route-list b { color: var(--paper); font-weight: 600; }
.route-list em { color: var(--accent-bright); font-style: normal; }

.recommendation-list { margin-top: 11px; display: grid; gap: 7px; }
.recommendation { display: grid; grid-template-columns: 33px 1fr auto; align-items: center; gap: 9px; border: 1px solid var(--line); padding: 8px; }
.recommendation-index { width: 30px; height: 30px; display: grid; place-items: center; border: 1px solid var(--line); color: var(--paper-dim); font: 9px/1 var(--mono); }
.recommendation-copy { display: grid; gap: 3px; }
.recommendation-copy b { font-size: 10px; }
.recommendation-copy small { color: var(--paper-dim); font-size: 8px; }
.recommendation button { border: 0; background: transparent; color: var(--accent-bright); font-size: 16px; cursor: pointer; }
.recommendation button:hover { transform: translateX(2px); }

.principle-note { margin-top: 25px; padding: 15px; border-left: 2px solid var(--accent); background: rgba(255,255,255,.025); }
.principle-note > span { color: var(--accent-bright); font: 8px/1 var(--mono); letter-spacing: .1em; }
.principle-note p { margin: 9px 0 0; color: var(--paper-soft); font: 12px/1.7 var(--serif); }
.principle-note em { color: var(--paper); font-style: normal; }
.live-dot { display: inline-flex; align-items: center; gap: 5px; color: var(--paper-dim); font: 8px/1 var(--mono); }
.live-dot i { width: 5px; height: 5px; border-radius: 50%; background: var(--moss); box-shadow: 0 0 0 4px rgba(142,154,120,.1); }

.toast { position: fixed; left: 50%; bottom: 24px; z-index: 50; transform: translate(-50%, 20px); opacity: 0; pointer-events: none; padding: 10px 14px; background: var(--paper); color: var(--ink); box-shadow: 0 14px 35px rgba(0,0,0,.3); font-size: 11px; transition: 180ms ease; }
.toast.show { opacity: 1; transform: translate(-50%, 0); }

@media (max-width: 1180px) {
    :root { --panel-width: 270px; --right-width: 290px; }
    .topbar { grid-template-columns: minmax(260px, 1fr) minmax(200px, .65fr) auto; gap: 14px; }
    .top-actions .text-button:first-of-type { display: none; }
    .workspace { grid-template-columns: var(--panel-width) minmax(500px, 1fr); }
    .panel-right { grid-column: 1 / -1; display: grid; grid-template-columns: 1.05fr 1fr 1fr; gap: 20px; border-left: 0; border-top: 1px solid var(--line); }
    .panel-right > .panel-heading { grid-column: 1 / -1; }
    .selection-card, .explanation-section, .recommendation-section { margin-top: 0; }
    .principle-note { display: none; }
}

@media (max-width: 820px) {
    .topbar { height: auto; min-height: 72px; grid-template-columns: 1fr auto; padding: 12px 14px; }
    .project-meta { display: none; }
    .text-button { display: none; }
    .primary-button { padding: 9px 10px; }
    .primary-button span:first-child { display: none; }
    .workspace { min-height: calc(100vh - 72px); display: flex; flex-direction: column; }
    .panel-left { order: 2; border-right: 0; border-top: 1px solid var(--line); }
    .canvas-column { order: 1; min-height: calc(100vh - 72px); }
    .panel-right { order: 3; display: block; }
    .panel-right > section, .panel-right > aside { margin-top: 20px; }
    .panel { padding: 20px 16px; }
    .program-list { display: grid; grid-template-columns: 1fr 1fr; }
    .program-row:nth-child(odd) { border-right: 1px solid var(--line); padding-right: 10px; }
    .program-row:nth-child(even) { padding-left: 10px; }
    .diagram-frame { min-height: 570px; }
    .canvas-toolbar { padding: 0 10px; }
    .zoom-control { display: none; }
    .diagram-caption { padding: 13px 14px 0; }
    .diagram-caption span { display: none; }
    .canvas-footer { align-items: flex-start; flex-direction: column; }
    .logic-strip { grid-template-columns: 1fr 1fr; }
    .logic-strip article { border-bottom: 1px solid var(--line); }
    .logic-strip article:nth-child(2) { border-right: 0; }
}

@media (max-width: 520px) {
    .brand-kicker, .beta-badge { display: none; }
    .brand-title-row { margin-top: 0; }
    .brand-title-row h1 { font-size: 16px; }
    .back-link { width: 34px; height: 34px; }
    .canvas-tools .tool-button:first-of-type { display: none; }
    .view-tab { padding: 0 9px; font-size: 10px; }
    .program-list { display: block; }
    .program-row:nth-child(odd), .program-row:nth-child(even) { border-right: 0; padding-left: 0; padding-right: 0; }
}

@media (prefers-reduced-motion: reduce) {
    *, *::before, *::after { scroll-behavior: auto !important; transition-duration: .01ms !important; animation-duration: .01ms !important; }
}