:root {
  color-scheme: light;
  --ink: #182235;
  --muted: #718096;
  --line: #e5eaf1;
  --panel: #ffffff;
  --canvas: #f7f9fc;
  --blue: #2667e8;
  --blue-soft: #eaf1ff;
  --orange: #ee8b3a;
  --red: #d6555f;
  --shadow: 0 8px 28px rgba(34, 52, 84, .08);
  font-family: Inter, ui-sans-serif, system-ui, -apple-system, BlinkMacSystemFont, "Segoe UI", sans-serif;
}

* { box-sizing: border-box; }
html, body { height: 100%; overflow: hidden; }
body { margin: 0; min-width: 400px; color: var(--ink); background: #f1f4f8; }
button, textarea { font: inherit; }
button { cursor: pointer; }

.app-header { height: 44px; display: flex; align-items: center; justify-content: space-between; padding: 0 10px; background: var(--panel); border-bottom: 1px solid var(--line); }
.section-kicker { margin: 0 0 4px; color: #91a0b5; font-size: 10px; font-weight: 800; letter-spacing: .18em; }
h1, h2, p { margin-top: 0; }
h1 { margin-bottom: 0; font-size: 17px; letter-spacing: -.02em; }
h2 { margin-bottom: 0; font-size: 14px; letter-spacing: -.01em; }
.header-actions { display: flex; gap: 6px; }
.button { border: 1px solid transparent; border-radius: 6px; padding: 5px 10px; font-size: 11px; font-weight: 700; transition: .15s ease; }
.button:hover { transform: translateY(-1px); }
.button-ghost { color: #43516a; border-color: var(--line); background: white; }
.save-status-button { display: inline-flex; align-items: center; justify-content: center; width: 17px; height: 17px; padding: 0; border: 0; border-radius: 50%; background: transparent; }
.save-status-button:hover { transform: none; }
.save-status-dot { display: block; width: 7px; height: 7px; border-radius: 50%; background: #aab4c2; }
.save-status-dot.is-saved { background: #2f9d6d; }
.button-primary { color: white; background: #28364f; }
.load-menu { position: relative; }

.app-shell { display: grid; grid-template-columns: 140px minmax(0, 1fr) 180px; grid-template-rows: minmax(0, 1fr); height: calc(100vh - 44px); height: calc(100dvh - 44px); min-height: 0; overflow: hidden; }
.sidebar { background: var(--panel); }
.left-panel { min-height: 0; overflow-y: auto; overflow-x: hidden; border-right: 1px solid var(--line); }
.right-panel { min-height: 0; overflow-y: auto; border-left: 1px solid var(--line); }
.simulation-panel { display: flex; align-items: center; justify-content: space-between; margin: 9px 20px 0; padding: 7px 8px; background: white; border: 1px solid var(--line); border-radius: 7px; box-shadow: 0 3px 10px rgba(34, 52, 84, .05); }
.simulation-panel[hidden] { display: none; }
.simulation-time span { display: block; color: #9aa7b9; font-size: 8px; font-weight: 800; letter-spacing: .12em; }
.simulation-time strong { display: block; margin-top: 2px; color: #35445e; font-size: 13px; font-variant-numeric: tabular-nums; }
.simulation-speed-select { min-width: 52px; padding: 4px 5px; color: #596982; background: #f8fafc; border: 1px solid var(--line); border-radius: 5px; font-size: 10px; font-weight: 800; }
.simulation-speed-select:hover { color: var(--blue); border-color: #a6bde9; background: var(--blue-soft); }
.panel-section { padding: 6px; border-bottom: 1px solid var(--line); }
.left-panel > .panel-section:first-child .section-heading { align-items: center; margin-bottom: 4px; }
.section-heading { display: flex; justify-content: space-between; align-items: flex-start; margin-bottom: 4px; }
.section-heading.compact { margin-bottom: 15px; }
.part-count { display: grid; place-items: center; min-width: 16px; padding: 1px 3px; border-radius: 10px; color: var(--blue); background: var(--blue-soft); font-size: 9px; font-weight: 400; }
.add-buttons { display: grid; grid-template-columns: repeat(2, minmax(0, 1fr)); gap: 2px; }
.part-button { position: relative; display: grid; grid-template-columns: 1fr; grid-template-areas: "icon" "label"; align-items: center; gap: 2px; min-width: 0; width: 100%; padding: 5px 4px 4px; text-align: center; color: var(--ink); background: #fbfcfe; border: 1px solid var(--line); border-radius: 9px; transition: .15s ease; cursor: grab; touch-action: pan-y; }
.part-button:active { cursor: grabbing; }
.part-button:hover { border-color: #a6bde9; background: #f5f8ff; transform: translateY(-1px); }
.part-button strong { display: block; font-size: 7.5px; font-weight: 400; line-height: 1.2; }
.part-label { grid-area: label; min-width: 0; }
.part-usage-count { position: absolute; top: 4px; right: 4px; min-width: 16px; padding: 1px 3px; color: var(--muted); background: #eef2f7; border-radius: 10px; font-size: 9px; font-weight: 800; text-align: center; }
.part-icon { display: grid; grid-area: icon; place-items: center; justify-self: center; width: 30px; height: 21px; }
.part-icon svg { display: block; width: 100%; height: 100%; overflow: visible; }
.part-icon-path { fill: none; stroke: #7387a6; stroke-width: .5; stroke-linecap: round; stroke-linejoin: round; }
.part-icon-train { stroke: #7f3d35; stroke-width: .12; }
.part-icon-text { fill: #4c5b73; font-size: 1.8px; font-weight: 700; }
.part-icon-connector { stroke: white; stroke-width: .1; }
.part-icon-connector.male { fill: #ee8b3a; }
.part-icon-connector.female { fill: white; stroke: #b9c3d1; }
.tool-button { display: grid; justify-items: center; gap: 3px; padding: 8px 2px 7px; color: #4c5b73; background: #f8fafc; border: 1px solid var(--line); border-radius: 7px; font-size: 18px; }
.tool-button span { font-size: 9px; font-weight: 700; }
.tool-button:hover { color: var(--blue); border-color: #a6bde9; background: var(--blue-soft); }
.tool-button.danger:hover { color: var(--red); border-color: #efb7bc; background: #fff2f3; }
.workspace { display: flex; flex-direction: column; min-width: 0; background: var(--canvas); }
.zoom-controls { position: absolute; z-index: 2; top: 14px; right: 14px; display: flex; align-items: center; gap: 4px; padding: 3px; background: rgba(245, 247, 251, .94); border: 1px solid var(--line); border-radius: 7px; box-shadow: 0 3px 10px rgba(34, 52, 84, .08); }
.selection-controls { position: absolute; z-index: 2; top: 14px; left: 50%; display: flex; align-items: center; gap: 4px; padding: 3px; background: rgba(245, 247, 251, .94); border: 1px solid var(--line); border-radius: 7px; box-shadow: 0 3px 10px rgba(34, 52, 84, .08); transform: translateX(-50%); visibility: hidden; opacity: 0; pointer-events: none; }
.selection-controls.is-visible { visibility: visible; opacity: 1; pointer-events: auto; }
.selection-controls .tool-button { min-width: 48px; padding: 4px 6px; }
.selection-menu { position: relative; }
.selection-controls .menu-button { min-width: 30px; padding: 4px 5px; font-size: 20px; line-height: 1; }
.selection-menu-popup { position: absolute; z-index: 3; top: calc(100% + 6px); right: 0; min-width: 154px; padding: 4px; background: white; border: 1px solid var(--line); border-radius: 7px; box-shadow: 0 5px 14px rgba(34, 52, 84, .14); }
.selection-menu-popup[hidden] { display: none; }
.sample-list[hidden], .load-menu-divider[hidden] { display: none; }
.load-menu-divider { height: 1px; margin: 4px 5px; background: var(--line); }
.selection-menu-item { display: block; width: 100%; padding: 8px 9px; color: #4c5b73; background: transparent; border: 0; border-radius: 5px; font-size: 10px; text-align: left; white-space: nowrap; }
.selection-menu-item:hover { color: var(--blue); background: var(--blue-soft); }
.zoom-button, .zoom-value { display: grid; place-items: center; height: 25px; border: 0; border-radius: 5px; color: #52627d; background: transparent; font-size: 16px; line-height: 1; }
.zoom-button { width: 25px; }
.zoom-value { width: 42px; padding: 0px; font-size: 10px; font-weight: 800; }
.zoom-button:hover, .zoom-value:hover { color: var(--blue); background: white; }
.floor-filter { height: 25px; padding: 0 4px; color: #52627d; background: transparent; border: 0; border-radius: 5px; font-size: 10px; font-weight: 800; }
.floor-filter:hover:not(:disabled) { color: var(--blue); background: white; }
.floor-filter:disabled { color: #aab4c2; cursor: not-allowed; }
.shortcut-overlay { position: fixed; z-index: 10; inset: 0; display: grid; place-items: center; padding: 20px; background: rgba(24, 34, 53, .32); }
.shortcut-overlay[hidden] { display: none; }
.shortcut-dialog { width: min(420px, calc(100vw - 40px)); max-height: calc(100vh - 40px); overflow: auto; padding: 18px 20px; background: white; border: 1px solid var(--line); border-radius: 12px; box-shadow: 0 12px 36px rgba(34, 52, 84, .2); }
.shortcut-dialog-header { display: flex; align-items: center; justify-content: space-between; gap: 12px; margin-bottom: 14px; }
.shortcut-dialog-header h2 { margin: 0; }
.shortcut-close { display: grid; place-items: center; width: 26px; height: 26px; padding: 0; color: #718096; background: #f8fafc; border: 1px solid #eef1f5; border-radius: 6px; font-size: 19px; line-height: 1; }
.shortcut-close:hover { color: var(--blue); background: var(--blue-soft); }
.shortcut-list { display: grid; grid-template-columns: max-content 1fr; gap: 9px 16px; margin: 0; align-items: center; color: #596982; font-size: 11px; }
.shortcut-list dt, .shortcut-list dd { margin: 0; }
.shortcut-list dt { color: var(--ink); white-space: nowrap; }
.shortcut-list kbd { display: inline-block; min-width: 18px; padding: 2px 5px; color: #43516a; background: #f1f4f8; border: 1px solid #d7dee8; border-bottom-width: 2px; border-radius: 4px; font-family: inherit; font-size: 10px; text-align: center; }
.shortcut-note { margin: 16px 0 0; color: var(--muted); font-size: 10px; line-height: 1.6; }
.canvas-wrap { position: relative; flex: 1; min-height: 0; padding: 4.5px; }
#layout-canvas, #layout-canvas * { user-select: none; -webkit-user-select: none; }
#layout-canvas { display: block; width: 100%; height: 100%; min-height: 0; background: white; border: 1px solid #dce3ed; border-radius: 10px; box-shadow: var(--shadow); touch-action: none; cursor: grab; }
#layout-canvas.is-panning { cursor: grabbing; }
.canvas-background { pointer-events: all; }
.empty-state { position: absolute; top: 50%; left: 50%; display: grid; justify-items: center; gap: 6px; transform: translate(-50%, -50%); color: #8b99ae; pointer-events: none; text-align: center; }
.empty-state[hidden] { display: none; }
.empty-state strong { color: #62718a; font-size: 13px; }
.empty-state span { font-size: 11px; }
.empty-mark { display: grid; place-items: center; width: 43px; height: 43px; margin-bottom: 4px; border: 1px dashed #b9c5d6; border-radius: 12px; color: #8fa2c0; font-size: 27px; font-weight: 300; }
.inspector { min-height: 0; }
.inspector-content { margin-top: 4px; }
.no-selection { padding: 12px 8px; color: #9aa7b9; background: #f8fafc; border: 1px dashed #dbe2eb; border-radius: 8px; font-size: 11px; line-height: 1.4; text-align: center; }
.property-title { display: flex; align-items: center; gap: 9px; margin-bottom: 10px; }
.property-name strong, .property-name small { display: block; }
.property-name strong { font-size: 12px; }
.property-name small { margin-top: 2px; color: var(--muted); font-size: 10px; }
.position-property { padding: 6px 8px; background: #f8fafc; border-radius: 6px; }
.position-values { display: flex; justify-content: space-between; gap: 4px; color: #35445e; font-size: 11px; font-weight: 400; }
.inspector-row { display: flex; align-items: center; justify-content: space-between; margin-top: 6px; padding: 6px 8px; color: #596982; background: #f8fafc; border-radius: 6px; font-size: 10px; }
.inspector-row output { color: #35445e; font-size: 11px; font-weight: 400; }
.switch-state-control { margin-top: 6px; padding: 6px 8px; color: #596982; background: #f8fafc; border-radius: 6px; font-size: 10px; }
.switch-state-control > label { display: block; margin-bottom: 5px; color: #9aa7b9; font-size: 9px; font-weight: 700; }
.switch-mode-control { display: flex; align-items: center; justify-content: space-between; gap: 8px; margin-top: 7px; color: #596982; font-size: 10px; font-weight: 700; }
.switch-mode-control select { min-width: 102px; padding: 4px 5px; color: #596982; background: white; border: 1px solid var(--line); border-radius: 5px; font-size: 10px; }
.train-color-control { display: flex; align-items: center; justify-content: space-between; gap: 8px; margin-top: 7px; color: #596982; font-size: 10px; font-weight: 700; }
.train-color-control select { min-width: 102px; padding: 4px 5px; color: #596982; background: white; border: 1px solid var(--line); border-radius: 5px; font-size: 10px; }
.train-speed-control { display: grid; gap: 4px; margin-top: 7px; color: #596982; font-size: 10px; font-weight: 700; }
.train-speed-input { display: flex; align-items: center; gap: 8px; }
.train-speed-input input { flex: 1; min-width: 0; accent-color: var(--blue); }
.train-speed-input output { min-width: 30px; color: #35445e; font-size: 11px; font-weight: 400; text-align: right; }
.text-content-control { display: grid; gap: 4px; margin-top: 7px; color: #596982; font-size: 10px; font-weight: 700; }
.text-content-control input { width: 100%; box-sizing: border-box; padding: 5px 6px; color: #35445e; background: white; border: 1px solid var(--line); border-radius: 5px; font-size: 11px; }
.switch-point-control + .switch-point-control { margin-top: 6px; }
.switch-point-control > label { display: block; margin-bottom: 4px; color: #9aa7b9; font-size: 9px; font-weight: 700; }
.switch-options { display: flex; gap: 4px; }
.switch-option { flex: 1; padding: 5px 4px; color: #596982; background: white; border: 1px solid var(--line); border-radius: 5px; font-size: 10px; }
.switch-option:hover, .switch-option.is-active { color: var(--blue); border-color: #a6bde9; background: var(--blue-soft); }

/* SVG rail styling */
.rail-instance { cursor: grab; }
.rail-instance:active { cursor: grabbing; }
.rail-height-shadow { fill: none; stroke: #61718d; stroke-width: .58; stroke-linecap: butt; stroke-linejoin: round; opacity: .2; pointer-events: none; }
.rail-shadow { fill: none; stroke: #1d3f78; stroke-width: 1; stroke-linecap: butt; stroke-linejoin: round; opacity: .16; pointer-events: none; }
.rail-line { fill: none; stroke: #3f6fba; stroke-width: .85; stroke-linecap: butt; stroke-linejoin: round; pointer-events: none; }
.rail-line.auto-switch { stroke: #d34b4b; }
.rail-line.fixed { stroke: #3b9b68; }
.rail-inner { fill: none; stroke: #b9cdf0; stroke-width: .24; stroke-linecap: butt; stroke-linejoin: round; pointer-events: none; }
.train-body { stroke: #7f3d35; stroke-width: .12; pointer-events: none; }
.train-hit { fill: transparent; stroke: transparent; stroke-width: 1.2; }
.text-box { fill: rgba(255, 255, 255, .55); stroke: #cbd5e1; stroke-width: .08; stroke-dasharray: .22 .16; cursor: grab; }
.text-content { pointer-events: none; user-select: none; }
.rail-hit { fill: none; stroke: transparent; stroke-width: 1.2; stroke-linecap: round; stroke-linejoin: round; }
.connector { stroke: white; stroke-width: .1; cursor: crosshair; }
.connector.male { fill: #f3c38c; }
.connector.female { fill: white; stroke: white; }
.connector.selected { fill: #f6c34f; stroke: #8d6910; stroke-width: .14; }
.connector.connected { fill: transparent; stroke: white; }
.connector.invalid { stroke: #d34b4b; stroke-width: .14; }
.connector.invalid.male { fill: #f3c38c; }
.connector.invalid.female { fill: white; }
.switch-marker { fill: #f3c742; stroke: #8d6910; stroke-width: .06; stroke-linejoin: round; cursor: pointer; pointer-events: auto; }
.switch-marker:hover { fill: #ffe27a; }
.switch-marker.disabled { fill: #aeb5bf; stroke: #737b87; cursor: default; }
.switch-marker.disabled:hover { fill: #aeb5bf; }
.selection-outline { fill: none; stroke: var(--blue); stroke-width: .05; stroke-dasharray: .2 .14; opacity: .78; pointer-events: none; }
.selection-box { fill: rgba(38, 103, 232, .08); stroke: var(--blue); stroke-width: .05; stroke-dasharray: .2 .14; opacity: .8; pointer-events: none; }
.connection-line { stroke: #3f6fba; stroke-width: .16; stroke-dasharray: .22 .28; stroke-linecap: round; opacity: .8; pointer-events: none; }
.connection-line.invalid { stroke: #d34b4b; }
.route-preview { opacity: .42; pointer-events: none; }
.route-preview .rail-line { stroke: #5d8fe0; }
.route-preview .rail-inner { stroke: #d1e0fa; }
.route-preview-connector { fill: #5d8fe0; stroke: white; stroke-width: .08; }
.route-preview-target { fill: none; stroke: #5d8fe0; stroke-width: .1; stroke-dasharray: .25 .18; pointer-events: none; }
.route-preview-target.invalid { stroke: #d34b4b; }
.direct-connection-preview { fill: none; stroke: #d34b4b; stroke-width: .12; stroke-dasharray: .28 .2; stroke-linecap: round; opacity: .9; pointer-events: none; }

@media (max-width: 720px) {
  .app-shell { grid-template-columns: 72px minmax(0, 1fr) 100px; }
  .panel-section { padding: 4px; }
  .add-buttons { grid-template-columns: 1fr; }
}

@media (orientation: portrait) {
  .app-shell { grid-template-columns: 160px minmax(0, 1fr); grid-template-rows: minmax(0, 1fr) 30vh; }
  .left-panel { grid-column: 1; grid-row: 1 / span 2; }
  .workspace { grid-column: 2; grid-row: 1; }
  .right-panel { grid-column: 2; grid-row: 2; height: 30vh; border-top: 1px solid var(--line); border-left: 0; }
  .selection-controls { top: auto; bottom: 14px; }
  .selection-controls .selection-menu-popup { top: auto; bottom: calc(100% + 6px); }
  .load-menu-popup { top: calc(100% + 6px); bottom: auto; max-height: calc(100dvh - 54px); overflow-y: auto; }
}

@media (orientation: portrait) and (max-width: 720px) {
  .app-shell { grid-template-columns: 72px minmax(0, 1fr); }
}