/* ===== Variables ===== */
:root {
  --bg:          #FBFBFA;
  --surface:     #FFFFFF;
  --ink:         #1B1C1E;
  --muted:       #71767E;
  --line:        #E3E6EA;
  --node-border: #C9CDD3;
  --node-fill:   #FFFFFF;
  --accent:      #34568B;
  --accent-soft: #EAEFF7;
  --danger:      #9A4A3C;
  --radius:      8px;
}

/* ===== Reset ===== */
*, *::before, *::after { box-sizing: border-box; }
html, body { height: 100%; margin: 0; }

body {
  font-family: -apple-system, BlinkMacSystemFont, "Segoe UI", Roboto, Helvetica, Arial, sans-serif;
  color: var(--ink);
  background: var(--bg);
  font-size: 14px;
  line-height: 1.45;
  -webkit-font-smoothing: antialiased;
}

/* ===== App shell ===== */
.app {
  display: flex;
  flex-direction: column;
  height: 100vh;
  overflow: hidden;
}

/* ===== Header ===== */
header {
  display: flex;
  align-items: center;
  gap: 12px;
  padding: 10px 16px;
  border-bottom: 1px solid var(--line);
  background: var(--surface);
  flex-shrink: 0;
  flex-wrap: wrap;
  z-index: 10;
}

.header-brand {
  display: flex;
  flex-direction: column;
  gap: 1px;
  white-space: nowrap;
}
.header-brand h1 {
  font-size: 15px;
  font-weight: 600;
  margin: 0;
  letter-spacing: -0.01em;
}
.header-brand .sub {
  font-size: 11px;
  color: var(--muted);
}

/* ===== Main area ===== */
main {
  flex: 1;
  display: flex;
  min-height: 0;
  overflow: hidden;
}

.canvas-wrap {
  flex: 1;
  position: relative;
  min-width: 0;
}