:root{--bg:#f3f4f6;--panel:#fff;--ink:#1a1a1a;--muted:#6b7280;--line:#e5e7eb;--accent:#2563eb;--accent-ink:#fff;--shadow:0 6px 24px rgba(0,0,0,.12),0 1px 3px rgba(0,0,0,.08);--radius:12px;--font:"Inter",system-ui,-apple-system,"Segoe UI",Roboto,sans-serif}
*{box-sizing:border-box}
html,body{margin:0;height:100%;font-family:var(--font);color:var(--ink);background:var(--bg);-webkit-font-smoothing:antialiased}
button{font:inherit;color:inherit;background:none;border:0;cursor:pointer;border-radius:8px;padding:6px 10px}
button:hover{background:rgba(0,0,0,.06)}
button.primary{background:var(--accent);color:var(--accent-ink);font-weight:600;padding:7px 14px}
button.primary:hover{background:#1d4ed8}
input{font:inherit;color:inherit}
.hidden{display:none!important}
.muted{color:var(--muted)}.small{font-size:12px}
.spacer{flex:1}
.logo{display:flex;align-items:center;gap:8px;font-weight:700;font-size:18px;text-decoration:none;color:inherit;letter-spacing:-.01em}
.logo-mark{width:22px;height:22px;border-radius:6px;background:var(--ink);position:relative;flex:none}
.logo-mark::after{content:"";position:absolute;inset:4px;border-radius:3px;background:#ffd23f}

/* ---------- home ---------- */
.topbar{display:flex;align-items:center;gap:12px;padding:10px 16px;background:var(--panel);border-bottom:1px solid var(--line)}
.boards{max-width:1100px;margin:0 auto;padding:28px 20px}
.boards h1{font-size:22px;margin:0 0 18px}
.board-grid{display:grid;grid-template-columns:repeat(auto-fill,minmax(240px,1fr));gap:16px}
.board-card{background:var(--panel);border:1px solid var(--line);border-radius:var(--radius);overflow:hidden;cursor:pointer;transition:box-shadow .15s,transform .15s;display:flex;flex-direction:column;text-decoration:none;color:inherit}
.board-card:hover{box-shadow:var(--shadow);transform:translateY(-1px)}
.board-thumb{height:130px;background:#fafafa url("data:image/svg+xml,%3Csvg xmlns='http://www.w3.org/2000/svg' width='20' height='20'%3E%3Cpath d='M20 0H0v20' fill='none' stroke='%23e5e7eb'/%3E%3C/svg%3E");display:flex;align-items:center;justify-content:center;color:#d1d5db;font-size:36px}
.board-meta{padding:12px 14px;display:flex;align-items:center;gap:8px}
.board-meta .name{font-weight:600;flex:1;white-space:nowrap;overflow:hidden;text-overflow:ellipsis}
.board-meta .more{padding:2px 8px;font-size:18px;line-height:1}
.card-menu{position:absolute;background:var(--panel);border:1px solid var(--line);border-radius:10px;box-shadow:var(--shadow);padding:6px;display:flex;flex-direction:column;min-width:150px;z-index:20}
.card-menu button{text-align:left}
.card-menu button.danger{color:#dc2626}
.login{position:fixed;inset:0;display:flex;align-items:center;justify-content:center;background:var(--bg)}
.login-card{background:var(--panel);padding:32px;border-radius:16px;box-shadow:var(--shadow);display:flex;flex-direction:column;gap:12px;width:340px}
.login-card input{padding:10px 12px;border:1px solid var(--line);border-radius:8px}
.login-card .err{color:#dc2626;font-size:13px;min-height:16px}

/* ---------- editor ---------- */
body.editor{overflow:hidden;background:#fff}
.stage{position:fixed;inset:0;overflow:hidden;background:#fbfbfb;touch-action:none}
#svg{width:100%;height:100%;display:block;user-select:none}
#svg.tool-hand{cursor:grab}#svg.tool-hand.panning{cursor:grabbing}
#svg.tool-sticky,#svg.tool-text,#svg.tool-shape,#svg.tool-frame,#svg.tool-connector,#svg.tool-image{cursor:crosshair}
#svg.tool-pen{cursor:crosshair}
.topbar.floating{position:fixed;top:12px;left:12px;right:12px;z-index:10;border:1px solid var(--line);border-radius:var(--radius);box-shadow:var(--shadow);padding:8px 12px;pointer-events:auto}
.board-name{border:1px solid transparent;border-radius:8px;padding:5px 8px;font-weight:600;font-size:15px;min-width:120px;max-width:360px;background:transparent}
.board-name:hover{border-color:var(--line)}.board-name:focus{outline:none;border-color:var(--accent);background:#fff}
.presence{display:flex;gap:-4px}
.presence .avatar{width:28px;height:28px;border-radius:50%;color:#fff;font-size:12px;font-weight:700;display:flex;align-items:center;justify-content:center;border:2px solid #fff;margin-left:-6px}
.menu{position:relative}
.dropdown{position:absolute;top:calc(100% + 6px);right:0;background:var(--panel);border:1px solid var(--line);border-radius:10px;box-shadow:var(--shadow);padding:6px;display:flex;flex-direction:column;min-width:160px;z-index:30}
.dropdown button{text-align:left;white-space:nowrap}
.toolbar{position:fixed;left:12px;top:50%;transform:translateY(-50%);z-index:10;background:var(--panel);border:1px solid var(--line);border-radius:var(--radius);box-shadow:var(--shadow);padding:6px;display:flex;flex-direction:column;gap:2px}
.toolbar button{width:40px;height:40px;padding:8px;display:flex;align-items:center;justify-content:center}
.toolbar button svg{width:22px;height:22px}
.toolbar button.active{background:var(--ink);color:#fff}
.toolbar .sep{height:1px;background:var(--line);margin:4px 6px}
.toolbar .menu .dropdown{top:0;left:calc(100% + 8px);right:auto}
.dropdown.shapes{flex-direction:row;flex-wrap:wrap;width:184px;min-width:0}
.dropdown.shapes button{width:40px;height:40px}
.zoombar{position:fixed;right:12px;bottom:12px;z-index:10;background:var(--panel);border:1px solid var(--line);border-radius:10px;box-shadow:var(--shadow);display:flex;padding:4px;gap:2px}
.zoombar button{padding:6px 10px;min-width:36px;font-size:13px}
.ctx{position:fixed;z-index:12;background:var(--panel);border:1px solid var(--line);border-radius:10px;box-shadow:var(--shadow);padding:5px;display:flex;align-items:center;gap:3px;transform:translate(-50%,-100%)}
.ctx button{padding:5px 7px;font-size:13px;display:flex;align-items:center;gap:4px}
.ctx button svg{width:18px;height:18px}
.ctx .sep{width:1px;height:22px;background:var(--line);margin:0 3px}
.ctx .swatch{width:20px;height:20px;border-radius:5px;border:1px solid rgba(0,0,0,.15);display:inline-block}
.ctx select{font:inherit;font-size:13px;border:1px solid var(--line);border-radius:6px;padding:3px 4px;background:#fff}
.ctx input[type=color]{width:26px;height:26px;border:0;padding:0;background:none;cursor:pointer}
.palette{position:absolute;top:calc(100% + 6px);left:0;background:var(--panel);border:1px solid var(--line);border-radius:10px;box-shadow:var(--shadow);padding:8px;display:grid;grid-template-columns:repeat(6,24px);gap:6px;z-index:40}
.palette .swatch{width:24px;height:24px;cursor:pointer}
.palette .swatch:hover{transform:scale(1.15)}
#cursors{position:absolute;inset:0;pointer-events:none;overflow:hidden}
.rcursor{position:absolute;left:0;top:0;pointer-events:none;transition:transform .08s linear;will-change:transform}
.rcursor svg{width:18px;height:18px;display:block;filter:drop-shadow(0 1px 1px rgba(0,0,0,.3))}
.rcursor .label{position:absolute;left:14px;top:14px;color:#fff;font-size:11px;font-weight:600;padding:2px 6px;border-radius:6px;white-space:nowrap}
.help{position:fixed;right:12px;bottom:60px;z-index:20;background:var(--panel);border:1px solid var(--line);border-radius:12px;box-shadow:var(--shadow);padding:14px 16px;font-size:13px}
.help h3{margin:0 0 8px;font-size:14px}.help table td{padding:2px 10px 2px 0}.help td:first-child{font-family:ui-monospace,Menlo,monospace;color:var(--muted)}
.toast{position:fixed;left:50%;bottom:24px;transform:translateX(-50%);background:var(--ink);color:#fff;padding:8px 14px;border-radius:8px;font-size:13px;z-index:50}

/* ---------- canvas items ---------- */
.item{cursor:move}
.item .txt{width:100%;height:100%;display:flex;flex-direction:column;padding:8px;overflow:hidden;font-family:var(--font);line-height:1.25;word-wrap:break-word;overflow-wrap:anywhere;box-sizing:border-box}
.item .txt p{margin:0}
.item .txt a{color:#2563eb}
.item.text .txt{padding:0;overflow:visible;white-space:pre-wrap}
.item.text foreignObject{overflow:visible}
.item.frame .frame-title{font-size:14px;fill:#555;font-weight:600;font-family:var(--font)}
.item.card .card-body{width:100%;height:100%;background:#fff;border-radius:8px;box-shadow:0 1px 3px rgba(0,0,0,.15);overflow:hidden;font-family:var(--font);display:flex;flex-direction:column;box-sizing:border-box}
.item.card .card-title{padding:10px 12px;font-size:14px;overflow:hidden;flex:1}
.item.card .card-title p{margin:0}
.item.card .card-desc{padding:0 12px 10px;font-size:12px;color:#666}
.conn{cursor:pointer}.conn .hit{stroke:transparent;stroke-width:14;fill:none}
.conn-caption{font-family:var(--font);font-size:12px}
.sel-box{fill:none;stroke:#2563eb;stroke-width:1.5;vector-effect:non-scaling-stroke;pointer-events:none}
.handle{fill:#fff;stroke:#2563eb;stroke-width:1.5;vector-effect:non-scaling-stroke}
.handle.nw,.handle.se{cursor:nwse-resize}.handle.ne,.handle.sw{cursor:nesw-resize}.handle.n,.handle.s{cursor:ns-resize}.handle.e,.handle.w{cursor:ew-resize}
.marquee{fill:rgba(37,99,235,.08);stroke:#2563eb;stroke-width:1;vector-effect:non-scaling-stroke;pointer-events:none}
.remote-sel{fill:none;stroke-width:2;vector-effect:non-scaling-stroke;pointer-events:none;stroke-dasharray:4 3}
.anchor{fill:#fff;stroke:#2563eb;stroke-width:1.5;vector-effect:non-scaling-stroke;cursor:crosshair;opacity:0}
.item:hover .anchor,#svg.tool-connector .item .anchor{opacity:1}
.conn-end{fill:#fff;stroke:#2563eb;stroke-width:1.5;vector-effect:non-scaling-stroke;cursor:move}
.edit-host{position:absolute;left:0;top:0;pointer-events:none}
.text-editor{position:absolute;pointer-events:auto;outline:none;overflow:auto;font-family:var(--font);line-height:1.25;padding:8px;word-wrap:break-word;overflow-wrap:anywhere;box-sizing:border-box;transform-origin:0 0;background:transparent}
.text-editor p{margin:0}
.snapline{stroke:#e6007a;stroke-width:1;vector-effect:non-scaling-stroke;pointer-events:none}
@media (max-width:720px){.topbar.floating .small,.help{display:none}.board-name{max-width:140px}}