:root {
  --bg1: #0b1020; --bg2: #1b2547;
  --panel: rgba(16, 22, 44, .72); --line: rgba(255, 255, 255, .12);
  --fg: #e8ecf8; --mut: #94a0c4; --acc: #5ec8ff;
  color-scheme: dark;
}
* { box-sizing: border-box; }
html, body { margin: 0; height: 100%; overflow: hidden; }
body {
  font: 14px/1.45 system-ui, -apple-system, "Segoe UI", Roboto, sans-serif; color: var(--fg);
  background: radial-gradient(ellipse at 50% 40%, var(--bg2), var(--bg1) 70%);
  user-select: none; -webkit-user-select: none;
}
#c { position: fixed; inset: 0; width: 100%; height: 100%; display: block; touch-action: none; cursor: grab; }
#c.dragging { cursor: grabbing; }
#c.hover { cursor: pointer; }

.panel {
  position: fixed; background: var(--panel); border: 1px solid var(--line); border-radius: 14px;
  backdrop-filter: blur(10px); -webkit-backdrop-filter: blur(10px); padding: 14px 16px;
}
.panel h3 { margin: 0 0 10px; font-size: 12px; letter-spacing: .08em; text-transform: uppercase; color: var(--mut); }

#top {
  position: fixed; top: 0; left: 0; right: 0; display: flex; gap: 16px; align-items: center;
  justify-content: space-between; padding: 12px 16px; pointer-events: none; flex-wrap: wrap;
}
#top > * { pointer-events: auto; }
.brand { display: flex; align-items: center; gap: 10px; }
.brand .logo { font-size: 28px; color: var(--acc); }
.brand b { display: block; font-size: 17px; }
.brand small { color: var(--mut); }
.tools { display: flex; gap: 8px; flex-wrap: wrap; align-items: center; }

button {
  font: inherit; color: var(--fg); cursor: pointer; background: rgba(255, 255, 255, .06);
  border: 1px solid var(--line); border-radius: 10px; padding: 7px 12px; transition: .15s;
}
button:hover { background: rgba(255, 255, 255, .13); }
button:focus-visible { outline: 2px solid var(--acc); outline-offset: 2px; }
button.on { background: var(--acc); color: #05263a; border-color: transparent; font-weight: 600; }
.seg { display: flex; background: var(--panel); border: 1px solid var(--line); border-radius: 12px; padding: 3px; gap: 2px; backdrop-filter: blur(10px); }
.seg button { border: 0; background: transparent; padding: 6px 10px; }
.seg button.on { background: var(--acc); }
.tog { background: var(--panel); backdrop-filter: blur(10px); }

#list { left: 16px; top: 84px; width: 210px; max-height: calc(100% - 150px); overflow: auto; }
#molList { display: flex; flex-direction: column; gap: 6px; }
.mol {
  display: flex; align-items: center; gap: 10px; text-align: left; width: 100%; padding: 8px 10px;
}
.mol .k { width: 18px; color: var(--mut); font-size: 12px; }
.mol .n { flex: 1; font-weight: 600; }
.mol .f { color: var(--mut); font-size: 13px; }
.mol.on { color: var(--fg); font-weight: 400; background: rgba(94, 200, 255, .18); border-color: var(--acc); }
.mol.on .f, .mol.on .k { color: var(--fg); }

#info { right: 16px; top: 84px; width: 290px; max-height: calc(100% - 150px); overflow: auto; }
#info .title { display: flex; align-items: baseline; justify-content: space-between; gap: 8px; }
#info h2 { margin: 0; font-size: 20px; }
.formula { font-size: 18px; color: var(--acc); font-weight: 600; white-space: nowrap; }
#info p { margin: 6px 0 10px; color: var(--mut); }
dl { display: grid; grid-template-columns: auto 1fr; gap: 3px 12px; margin: 0 0 12px; }
dt { color: var(--mut); } dd { margin: 0; text-align: right; }
#legend { display: flex; flex-wrap: wrap; gap: 6px 12px; margin-bottom: 12px; }
#legend span { display: inline-flex; align-items: center; gap: 6px; font-size: 13px; }
#legend i { width: 12px; height: 12px; border-radius: 50%; border: 1px solid rgba(255, 255, 255, .35); }
#measure { border-top: 1px solid var(--line); padding-top: 10px; display: flex; flex-direction: column; gap: 4px; }
#measure b { font-size: 12px; letter-spacing: .08em; text-transform: uppercase; color: var(--mut); }
#mMeasure { min-height: 40px; }
#mMeasure em { color: var(--acc); font-style: normal; font-weight: 600; }

#tip {
  position: fixed; pointer-events: none; padding: 5px 9px; border-radius: 8px; font-size: 13px;
  background: rgba(8, 12, 26, .9); border: 1px solid var(--line); transform: translate(12px, 12px); opacity: 0;
  transition: opacity .1s; white-space: nowrap;
}
#tip.show { opacity: 1; }
#help {
  position: fixed; left: 50%; bottom: 14px; transform: translateX(-50%); color: var(--mut); font-size: 13px;
  background: var(--panel); border: 1px solid var(--line); border-radius: 999px; padding: 7px 16px;
  backdrop-filter: blur(10px); text-align: center; max-width: calc(100% - 32px); pointer-events: none;
}
#help b { color: var(--fg); font-weight: 600; }

.overlay { position: fixed; inset: 0; display: grid; place-items: center; background: rgba(5, 8, 18, .85); }
.overlay[hidden] { display: none; }
.card { background: var(--panel); border: 1px solid var(--line); border-radius: 16px; padding: 22px 26px; max-width: 360px; }

@media (max-width: 820px) {
  #list { top: auto; bottom: 56px; left: 8px; right: 8px; width: auto; max-height: none; padding: 8px; }
  #list h3 { display: none; }
  #molList { flex-direction: row; overflow-x: auto; }
  .mol { width: auto; flex: none; }
  .mol .k, .mol .f { display: none; }
  #info { top: auto; bottom: 130px; right: 8px; left: 8px; width: auto; max-height: 30%; padding: 10px 12px; }
  #info dl, #legend, #measure { display: none; }
  #top { padding: 8px; }
  .brand small { display: none; }
  #help { bottom: 10px; font-size: 11px; border-radius: 12px; }
}

#molList h4 { margin: 10px 0 2px; font-size: 11px; letter-spacing: .06em; text-transform: uppercase; color: var(--acc); font-weight: 600; }
#molList h4:first-child { margin-top: 0; }
@media (max-width: 820px) { #molList h4 { display: none; } }
#info .title { flex-wrap: wrap; }