:root {
  --bg0: #0b0f1a;
  --bg1: #111827;
  --bg2: #1a2334;
  --bg3: #223049;
  --border: #2c3a55;
  --text: #e6edf7;
  --muted: #8fa3c0;
  --accent: #4cc9f0;
  --accent2: #7c6cff;
  --good: #35d07f;
  --warn: #ffb454;
  --bad: #ff5c7a;
  --mono: ui-monospace, "SF Mono", "Cascadia Code", "JetBrains Mono", Menlo, Consolas, monospace;
}

* { box-sizing: border-box; }

/* The hidden attribute must always win over display rules below (e.g. the
   flex container styles applied to .overlay / .output-tools). */
[hidden] { display: none !important; }

html, body {
  margin: 0;
  padding: 0;
  background:
    radial-gradient(1200px 600px at 15% -10%, rgba(76, 201, 240, .14), transparent 60%),
    radial-gradient(1000px 700px at 100% 0%, rgba(124, 108, 255, .12), transparent 55%),
    var(--bg0);
  color: var(--text);
  font-family: -apple-system, BlinkMacSystemFont, "Segoe UI", "PingFang SC", "Microsoft YaHei", Roboto, sans-serif;
  min-height: 100vh;
  line-height: 1.5;
}

/* ---------- top bar ---------- */
.topbar {
  display: flex;
  align-items: center;
  justify-content: space-between;
  gap: 16px;
  padding: 18px clamp(16px, 4vw, 40px);
  border-bottom: 1px solid var(--border);
  background: rgba(17, 24, 39, .7);
  backdrop-filter: blur(8px);
  position: sticky;
  top: 0;
  z-index: 10;
}
.brand { display: flex; gap: 14px; align-items: center; }
.logo { width: 42px; height: 42px; flex: none; }
.brand h1 { margin: 0; font-size: 20px; letter-spacing: .3px; }
.brand .accent { color: var(--accent); }
.tagline { margin: 2px 0 0; color: var(--muted); font-size: 12.5px; }
.badges { display: flex; gap: 8px; flex-wrap: wrap; justify-content: flex-end; }
.badge {
  font-size: 11.5px;
  padding: 5px 11px;
  border-radius: 999px;
  border: 1px solid var(--border);
  color: var(--muted);
  background: var(--bg2);
  white-space: nowrap;
}
.badge-engine.ok { color: var(--good); border-color: rgba(53,208,127,.4); }
.badge-engine.err { color: var(--bad); border-color: rgba(255,92,122,.4); }

/* ---------- layout ---------- */
.layout {
  display: grid;
  grid-template-columns: minmax(0, 5fr) minmax(0, 6fr);
  gap: 20px;
  padding: 22px clamp(16px, 4vw, 40px);
  align-items: start;
}
@media (max-width: 900px) { .layout { grid-template-columns: 1fr; } }

/* Right column groups the 3Dmol viewer and the results panel together so the
   structure frame stays on the right regardless of how many cards exist. */
.col-right {
  display: flex;
  flex-direction: column;
  gap: 20px;
  min-width: 0;
}


.card {
  background: linear-gradient(180deg, var(--bg2), var(--bg1));
  border: 1px solid var(--border);
  border-radius: 16px;
  padding: 20px;
  box-shadow: 0 12px 40px rgba(0, 0, 0, .35);
}
.panel-title {
  margin: 0 0 14px;
  font-size: 15px;
  letter-spacing: .5px;
  color: var(--accent);
  text-transform: uppercase;
  font-weight: 600;
}

/* ---------- fields ---------- */
.field { margin-bottom: 14px; }
.field label {
  display: block;
  font-size: 12.5px;
  color: var(--muted);
  margin-bottom: 6px;
}
textarea, input[type="number"], input[type="text"] {
  width: 100%;
  background: var(--bg0);
  border: 1px solid var(--border);
  border-radius: 10px;
  color: var(--text);
  padding: 10px 12px;
  font-family: var(--mono);
  font-size: 13px;
  transition: border-color .15s, box-shadow .15s;
}
textarea:focus, input:focus {
  outline: none;
  border-color: var(--accent);
  box-shadow: 0 0 0 3px rgba(76, 201, 240, .15);
}
textarea { resize: vertical; line-height: 1.45; }
.hint { font-size: 11.5px; color: var(--muted); margin-top: 5px; }
.tip { color: var(--accent); cursor: help; margin-left: 4px; }

.grid2 {
  display: grid;
  grid-template-columns: 1fr 1fr;
  gap: 12px;
}
@media (max-width: 480px) { .grid2 { grid-template-columns: 1fr; } }

.check {
  display: flex;
  align-items: center;
  gap: 8px;
  font-size: 13px;
  color: var(--text);
  margin: 4px 0 16px;
  cursor: pointer;
}
.check input { accent-color: var(--accent); width: 16px; height: 16px; }

/* ---------- presets ---------- */
.preset-row { display: flex; flex-wrap: wrap; gap: 8px; }
.chip {
  background: var(--bg3);
  border: 1px solid var(--border);
  color: var(--text);
  padding: 6px 13px;
  border-radius: 999px;
  font-size: 12.5px;
  cursor: pointer;
  transition: all .12s;
}
.chip:hover { border-color: var(--accent); color: var(--accent); }
.chip.active { background: var(--accent); border-color: var(--accent); color: #0b0f1a; font-weight: 600; }

/* ---------- SMILES generator ---------- */
.smiles-row {
  display: grid;
  grid-template-columns: minmax(0, 1fr) auto;
  gap: 8px;
  align-items: stretch;
}
.smiles-button {
  min-width: 142px;
  display: inline-flex;
  align-items: center;
  justify-content: center;
  gap: 8px;
  padding-inline: 14px;
}
.smiles-status { min-height: 1.5em; }
.smiles-status.ok { color: var(--good); }
.smiles-status.err { color: var(--bad); }
.mini-spinner {
  width: 14px;
  height: 14px;
  border: 2px solid rgba(230, 237, 247, .3);
  border-top-color: currentColor;
  border-radius: 50%;
  animation: spin .75s linear infinite;
}
@media (max-width: 560px) {
  .smiles-row { grid-template-columns: 1fr; }
  .smiles-button { width: 100%; }
}

/* ---------- buttons ---------- */
.actions { display: flex; gap: 10px; }
.btn {
  flex: 1;
  border: 1px solid var(--border);
  background: var(--bg3);
  color: var(--text);
  border-radius: 12px;
  padding: 11px 16px;
  font-size: 14px;
  cursor: pointer;
  transition: all .15s;
}
.btn:hover:not(:disabled) { border-color: var(--accent); }
.btn:disabled { opacity: .45; cursor: not-allowed; }
.btn-primary {
  background: linear-gradient(135deg, var(--accent), var(--accent2));
  border: none;
  color: #0b0f1a;
  font-weight: 700;
}
.btn-primary:hover { filter: brightness(1.08); }
.btn-primary:disabled { background: var(--bg3); color: var(--muted); }
.btn-small { flex: 0 0 auto; padding: 7px 14px; font-size: 12.5px; }

/* ---------- output ---------- */
.energy-block {
  text-align: center;
  padding: 22px 16px 18px;
  border: 1px solid var(--border);
  border-radius: 14px;
  background: radial-gradient(500px 200px at 50% 0%, rgba(76,201,240,.10), transparent 70%);
  margin-bottom: 14px;
}
.energy-val {
  font-family: var(--mono);
  font-size: clamp(22px, 3.4vw, 34px);
  font-weight: 700;
  color: var(--accent);
}
.energy-sub { margin-top: 6px; color: var(--muted); font: 13px var(--mono); }
.dim { color: var(--border); }

.stats {
  display: grid;
  grid-template-columns: repeat(4, 1fr);
  gap: 10px;
  margin-bottom: 14px;
}
.stat {
  background: var(--bg2);
  border: 1px solid var(--border);
  border-radius: 12px;
  text-align: center;
  padding: 10px 4px;
}
.stat-k { font: 700 19px var(--mono); color: var(--text); }
.stat-l { font-size: 11px; color: var(--muted); margin-top: 2px; }

.table-wrap { overflow-x: auto; border: 1px solid var(--border); border-radius: 12px; }
table { border-collapse: collapse; width: 100%; font-size: 12.5px; }
th, td { padding: 8px 10px; text-align: left; white-space: nowrap; }
th {
  background: var(--bg3);
  color: var(--muted);
  font-weight: 600;
  position: sticky;
  top: 0;
}
td { border-top: 1px solid var(--border); font-family: var(--mono); }
tr:hover td { background: rgba(76,201,240,.05); }
td.num, th.num { text-align: right; }
.sym { color: var(--accent); font-weight: 700; }

.output-tools { display: flex; gap: 10px; align-items: center; margin-top: 14px; }

.err {
  margin-top: 14px;
  border: 1px solid rgba(255,92,122,.4);
  background: rgba(255,92,122,.08);
  color: var(--bad);
  border-radius: 12px;
  padding: 12px 14px;
  font: 13px var(--mono);
  white-space: pre-wrap;
}

/* ---------- roadmap ---------- */
.roadmap {
  margin: 0 clamp(16px, 4vw, 40px) 22px;
}
.roadmap-grid {
  display: grid;
  grid-template-columns: 1fr 1fr;
  gap: 14px;
}
@media (max-width: 700px) { .roadmap-grid { grid-template-columns: 1fr; } }
.roadmap-item {
  display: flex;
  gap: 14px;
  align-items: center;
  border: 1px dashed var(--border);
  border-radius: 14px;
  padding: 16px;
  opacity: .72;
  background: var(--bg1);
}
.rm-emoji { font-size: 24px; }
.rm-title { font-weight: 600; }
.rm-desc { font-size: 12.5px; color: var(--muted); margin-top: 2px; }
.tag {
  font-size: 10.5px;
  color: var(--warn);
  border: 1px solid rgba(255,180,84,.4);
  border-radius: 999px;
  padding: 1px 8px;
  margin-left: 6px;
  vertical-align: 1px;
}

/* ---------- footer ---------- */
.footer {
  color: var(--muted);
  font-size: 12px;
  text-align: center;
  padding: 4px clamp(16px, 4vw, 40px) 40px;
}
.footer strong { color: var(--text); }

/* ---------- overlay ---------- */
.overlay {
  position: fixed;
  inset: 0;
  background: rgba(8, 11, 20, .78);
  backdrop-filter: blur(4px);
  display: flex;
  align-items: center;
  justify-content: center;
  z-index: 50;
}
.overlay-box { text-align: center; color: var(--text); }
.overlay-box p { color: var(--muted); font-size: 13px; }
.spinner {
  width: 46px;
  height: 46px;
  margin: 0 auto 16px;
  border: 4px solid var(--bg3);
  border-top-color: var(--accent);
  border-radius: 50%;
  animation: spin 0.9s linear infinite;
}
@keyframes spin { to { transform: rotate(360deg); } }
.sep { border: none; border-top: 1px solid var(--border); margin: 18px 0 14px; }
.sub-title { font-size: 13.5px; margin: 0 0 10px; color: var(--text); }
.hint-inline { font-size: 11px; color: var(--muted); font-weight: 400; }
.grid3 { display: grid; grid-template-columns: 1fr 1fr 1fr; gap: 10px; }
@media (max-width: 480px) { .grid3 { grid-template-columns: 1fr; } }
.btn-accent { border-color: rgba(124,108,255,.5); color: var(--accent2); }
.btn-secondary { background: linear-gradient(135deg, var(--warn), #ff8a3d); color: #1a1205; font-weight: 700; border:none; }
.btn-secondary:hover:not(:disabled) { filter: brightness(1.08); }
.tag-good { color: var(--good); border-color: rgba(53,208,127,.4); }
a.btn { text-decoration: none; max-width: 120px; }
.roadmap-item.disabled a.btn { color: var(--muted); }

.loadbar { margin-top: 14px; width: 260px; }
.loadbar-track {
  height: 8px;
  border-radius: 999px;
  background: var(--bg3);
  overflow: hidden;
  border: 1px solid var(--border);
}
.loadbar-fill {
  height: 100%;
  width: 0%;
  border-radius: 999px;
  background: linear-gradient(90deg, var(--accent), var(--accent2));
  transition: width .2s ease;
}
.loadbar.indeterminate .loadbar-fill {
  width: 35% !important;
  animation: loadbar-indeterminate 1.1s ease-in-out infinite;
}
@keyframes loadbar-indeterminate {
  0% { transform: translateX(-120%); }
  100% { transform: translateX(330%); }
}
.loadbar-text { margin: 8px 0 0; font: 12px var(--mono); color: var(--muted); }

.traj { margin-top: 14px; border: 1px solid var(--border); border-radius: 12px; padding: 12px 12px 8px; background: var(--bg1); }
.traj-title { margin: 0 0 8px; font-size: 12.5px; color: var(--muted); font-weight: 600; }
.traj-svg svg { width: 100%; height: auto; display: block; }

/* ---------- 3Dmol viewer ---------- */
.panel-mol .mol-container {
  height: 340px;
  border: 1px solid var(--border);
  border-radius: 12px;
  overflow: hidden;
  background: #0c1420;
  position: relative;
}
.mol-placeholder {
  position: absolute;
  inset: 0;
  display: flex;
  align-items: center;
  justify-content: center;
  color: var(--muted);
  font-size: 13px;
  text-align: center;
  padding: 12px;
}

.mol-head { display: flex; align-items: center; justify-content: space-between; gap: 8px; margin-bottom: 8px; }
.mol-head .panel-title { margin: 0; }
.mol-status {
  font: 12px var(--mono);
  color: var(--accent);
  border: 1px solid rgba(76,201,240,.45);
  border-radius: 999px;
  padding: 3px 11px;
  background: rgba(76,201,240,.08);
  white-space: nowrap;
}
.replay { margin-top: 10px; }
.replay-controls { display: flex; align-items: center; gap: 10px; }
.replay-btn { flex: 0 0 auto; padding: 5px 12px; font-size: 13px; }
#replay-slider { flex: 1; accent-color: var(--accent); margin: 0; }
.replay-label { font: 12px var(--mono); color: var(--muted); white-space: nowrap; }