:root {
  --ink: #142233;
  --panel: #1a2c41;
  --rule: #2d4762;
  --text: #dce6ee;
  --muted: #8ea3b6;
  --nitrogen: #8097ff;
  --sulfur: #f2c94c;
  --oxygen: #ff7a6b;
  --carbon: #b9c4ce;
  --verified: #7fdcc1;

  --font: "Martian Mono", ui-monospace, "SF Mono", Menlo, Consolas, monospace;
  --step--1: 0.8125rem;
  --step-0: 0.9375rem;
  --step-1: 1.125rem;
  --step-2: 1.5rem;
}

* { box-sizing: border-box; }

html { background: var(--ink); }

body {
  margin: 0;
  color: var(--text);
  font-family: var(--font);
  font-size: var(--step-0);
  font-variation-settings: "wdth" 87.5;
  line-height: 1.6;
  -webkit-font-smoothing: antialiased;
}

code {
  font-family: inherit;
  color: var(--sulfur);
}

:focus-visible {
  outline: 2px solid var(--sulfur);
  outline-offset: 2px;
}

.visually-hidden {
  position: absolute;
  width: 1px;
  height: 1px;
  overflow: hidden;
  clip: rect(0 0 0 0);
  white-space: nowrap;
}

.window {
  max-width: 68rem;
  margin: 2.5rem auto 3rem;
  padding: 0 1.25rem;
}

/* Banner: the same double-ruled box the terminal app draws. */
.banner {
  border: 4px double var(--nitrogen);
  padding: 1.5rem 1.75rem 1.25rem;
}

.banner h1 {
  margin: 0;
  font-size: clamp(1.25rem, 3.4vw, 2.125rem);
  font-weight: 600;
  font-variation-settings: "wdth" 112.5;
  line-height: 1.15;
  letter-spacing: -0.01em;
}

.banner-sub {
  margin: 0.5rem 0 1.25rem;
  color: var(--muted);
  font-size: var(--step--1);
}

.profile {
  display: grid;
  grid-template-columns: max-content 1fr;
  gap: 0.15rem 1.5rem;
  margin: 0;
  padding-top: 1rem;
  border-top: 1px solid var(--rule);
}

.profile dt { color: var(--muted); }
.profile dd { margin: 0; font-weight: 500; }

/* Mode choice */
.choose { margin-top: 2rem; }

.prompt,
.panel-title {
  margin: 0 0 1rem;
  font-size: var(--step-1);
  font-weight: 500;
}

.prompt::before {
  content: "> ";
  color: var(--nitrogen);
}

.choices {
  display: grid;
  grid-template-columns: repeat(auto-fit, minmax(17rem, 1fr));
  gap: 1rem;
}

.choice {
  display: grid;
  grid-template-columns: auto 1fr;
  gap: 0.15rem 0.75rem;
  padding: 1rem 1.25rem;
  text-align: left;
  font: inherit;
  color: inherit;
  background: transparent;
  border: 1px solid var(--rule);
  cursor: pointer;
}

.choice:hover { border-color: var(--muted); }

.choice .key { color: var(--nitrogen); font-weight: 600; grid-row: span 2; }
.choice .choice-title { font-weight: 600; }
.choice .choice-desc { color: var(--muted); font-size: var(--step--1); }

.choice[aria-pressed="true"] {
  background: var(--panel);
  border-color: var(--nitrogen);
  box-shadow: inset 4px 0 0 var(--nitrogen);
}

.choice[data-mode="internal"][aria-pressed="true"] {
  border-color: var(--sulfur);
  box-shadow: inset 4px 0 0 var(--sulfur);
}

.choice[data-mode="internal"] .key { color: var(--sulfur); }

/* Input panels */
.panel,
.results {
  margin-top: 2rem;
  padding: 1.5rem 1.75rem;
  background: var(--panel);
}

.hint {
  max-width: 72ch;
  margin: 0 0 1rem;
  color: var(--muted);
  font-size: var(--step--1);
}

.format {
  margin: 0 0 1rem;
  padding: 0.75rem 1rem;
  border-left: 2px solid var(--sulfur);
  font: inherit;
  font-size: var(--step--1);
  background: var(--ink);
  overflow-x: auto;
}

.toolbar {
  display: flex;
  flex-wrap: wrap;
  align-items: center;
  gap: 0.5rem 0.75rem;
  margin-bottom: 0.75rem;
}

.tool {
  padding: 0.4rem 0.8rem;
  font: inherit;
  font-size: var(--step--1);
  color: var(--text);
  background: transparent;
  border: 1px solid var(--rule);
  cursor: pointer;
}

.tool:hover { border-color: var(--muted); }

.file-tool input {
  position: absolute;
  opacity: 0;
  width: 1px;
  height: 1px;
}

.file-tool:focus-within { outline: 2px solid var(--sulfur); outline-offset: 2px; }

.check {
  display: inline-flex;
  align-items: center;
  gap: 0.5rem;
  font-size: var(--step--1);
  color: var(--muted);
}

.check input { accent-color: var(--nitrogen); }

textarea,
input[type="number"],
input[type="text"],
select {
  width: 100%;
  padding: 0.75rem 1rem;
  font: inherit;
  color: var(--text);
  background: var(--ink);
  border: 1px solid var(--rule);
  border-radius: 0;
}

textarea {
  min-height: 12rem;
  resize: vertical;
  line-height: 1.5;
  white-space: pre;
}

textarea::placeholder,
input::placeholder { color: #5f7488; }

.tabs {
  display: flex;
  gap: 0;
  margin-bottom: 1.25rem;
  border-bottom: 1px solid var(--rule);
}

.tabs [role="tab"] {
  padding: 0.6rem 1rem;
  font: inherit;
  color: var(--muted);
  background: transparent;
  border: 0;
  border-bottom: 2px solid transparent;
  margin-bottom: -1px;
  cursor: pointer;
}

.tabs [role="tab"][aria-selected="true"] {
  color: var(--text);
  border-bottom-color: var(--sulfur);
}

.fields {
  display: grid;
  grid-template-columns: 10rem 1fr 1fr;
  gap: 1rem;
  margin-bottom: 1rem;
}

.fields label {
  display: grid;
  gap: 0.35rem;
  font-size: var(--step--1);
  color: var(--muted);
}

.optional { color: #6b8094; }

.actions {
  display: flex;
  flex-wrap: wrap;
  align-items: center;
  gap: 1rem;
  margin-top: 1rem;
}

.convert {
  padding: 0.8rem 1.6rem;
  font: inherit;
  font-weight: 600;
  color: var(--ink);
  background: var(--sulfur);
  border: 0;
  cursor: pointer;
}

.convert:hover { background: #f7d873; }
.convert:disabled { opacity: 0.6; cursor: progress; }

.shortcut { color: var(--muted); font-size: var(--step--1); }

.error {
  margin: 1.5rem 0 0;
  padding: 0.85rem 1.1rem;
  color: var(--text);
  border-left: 4px solid var(--oxygen);
  background: rgba(255, 122, 107, 0.08);
}

.error::before { content: "Error: "; color: var(--oxygen); font-weight: 600; }

/* Results */
.verify {
  margin: 0 0 1.5rem;
  color: var(--verified);
}

.results h3 {
  margin: 1.5rem 0 0.75rem;
  font-size: var(--step-0);
  font-weight: 600;
}

.results-grid {
  display: grid;
  grid-template-columns: minmax(0, 1fr) minmax(0, 1fr);
  gap: 1.5rem;
  align-items: start;
}

.results-grid.single { grid-template-columns: minmax(0, 1fr); }

.results-grid > div h3 { margin-top: 0; }

.more { margin-top: 1.5rem; }

.more summary {
  cursor: pointer;
  color: var(--nitrogen);
  font-size: var(--step--1);
}

.more summary:focus-visible { outline: 2px solid var(--nitrogen); outline-offset: 2px; }

.more[open] summary { margin-bottom: 0.75rem; }

.viewer { margin: 0; }

.viewer svg {
  display: block;
  width: 100%;
  height: 22rem;
  background: var(--ink);
  border: 1px solid var(--rule);
  cursor: grab;
  touch-action: none;
}

.viewer svg:active { cursor: grabbing; }

.viewer figcaption {
  margin-top: 0.5rem;
  color: var(--muted);
  font-size: var(--step--1);
}

.legend { margin-left: 0.75rem; }

.legend i {
  display: inline-block;
  width: 0.6rem;
  height: 0.6rem;
  margin: 0 0.3rem 0 0.6rem;
  border-radius: 50%;
}

.el-N { background: var(--nitrogen); fill: var(--nitrogen); }
.el-C { background: var(--carbon); fill: var(--carbon); }
.el-O { background: var(--oxygen); fill: var(--oxygen); }
.el-S { background: var(--sulfur); fill: var(--sulfur); }
.el-X { background: var(--text); fill: var(--text); }

.viewer line {
  stroke: #56728f;
  stroke-width: 1.5;
  stroke-linecap: round;
}

.viewer circle { stroke: var(--ink); stroke-width: 0.75; }

.table-wrap {
  max-height: 32rem;
  overflow: auto;
  border: 1px solid var(--rule);
}

.table-wrap.short { max-height: 22rem; }

table.data {
  width: 100%;
  border-collapse: collapse;
  font-size: var(--step--1);
  font-variation-settings: "wdth" 75;
  font-variant-numeric: tabular-nums;
}

table.data th,
table.data td {
  padding: 0.35rem 0.75rem;
  text-align: left;
  white-space: nowrap;
}

table.data th {
  position: sticky;
  top: 0;
  font-weight: 600;
  background: var(--panel);
  border-bottom: 1px solid var(--rule);
}

table.data td.num,
table.data th.num { text-align: right; }

table.data tbody tr:nth-child(even) { background: rgba(255, 255, 255, 0.025); }

table.data .dim { color: #5f7488; }

table.data input {
  width: 7rem;
  padding: 0.3rem 0.5rem;
  font-variation-settings: "wdth" 75;
}

table.data input:disabled { opacity: 0.35; }

table.data input[aria-invalid="true"] {
  border-color: var(--oxygen);
  box-shadow: inset 0 0 0 1px var(--oxygen);
}

table.residue-form th,
table.residue-form td { padding: 0.3rem 0.4rem; }
table.residue-form input { width: 100%; min-width: 4.75rem; text-align: right; }
table.residue-form select {
  width: 100%;
  min-width: 4.5rem;
  padding: 0.3rem 0.4rem;
  font: inherit;
  font-variation-settings: "wdth" 75;
  color: var(--text);
  background: var(--ink);
  border: 1px solid var(--rule);
}
.residue-form th:nth-child(n+6):nth-child(-n+8) { color: var(--oxygen); }

table.data th .col-kind,
table.data th .col-name {
  display: block;
  line-height: 1.25;
}

table.data th .col-kind {
  margin-bottom: 0.15rem;
  color: var(--muted);
  font-size: 0.7rem;
  font-weight: 500;
  text-transform: lowercase;
  letter-spacing: 0.01em;
}

table.data th .col-name { font-weight: 600; }

.residue-form th:nth-child(n+6):nth-child(-n+8) .col-kind { color: #c98a82; }
.residue-form th:nth-child(n+6):nth-child(-n+8) .col-name { color: var(--oxygen); }

.atom-form td { padding-top: 0.3rem; padding-bottom: 0.3rem; }
.atom-form .row-residue { color: var(--muted); }
.atom-form input[data-field="name"] { width: 4.5rem; font-weight: 600; }
.atom-form input[data-field="x"],
.atom-form input[data-field="y"],
.atom-form input[data-field="z"] { width: 100%; min-width: 6.5rem; text-align: right; }

.remove {
  width: 2rem;
  height: 2rem;
  font: inherit;
  color: var(--muted);
  background: transparent;
  border: 1px solid transparent;
  cursor: pointer;
}

.remove:hover { color: var(--oxygen); border-color: var(--rule); }

.form-tools { margin-top: 0.75rem; }

.region-beta { color: var(--sulfur); }
.region-alpha-R { color: var(--nitrogen); }
.region-alpha-L { color: var(--oxygen); }

@media (max-width: 52rem) {
  .results-grid,
  .fields { grid-template-columns: 1fr; }
  .window { margin-top: 1.25rem; }
  .banner,
  .panel,
  .results { padding: 1.25rem; }
}