/* OpenSim application / data-canvas. Width tokens: sm 36rem, md 48rem,
   lg 64rem, xl 80rem. Width queries are centralized at the end. */
:root {
  color-scheme: light;
  --font-body: "Noto Sans CJK SC", "Source Han Sans SC", "PingFang SC", "Microsoft YaHei", sans-serif;
  --font-display: Georgia, "Noto Serif CJK SC", "Source Han Serif SC", "Songti SC", SimSun, serif;
  --font-mono: "SFMono-Regular", Consolas, "Liberation Mono", monospace;
  --text-sm: 0.875rem;
  --text-body: 1rem;
  --text-lg: 1.25rem;
  --text-h2: clamp(1.375rem, 1.2rem + 0.5vw, 1.75rem);
  --text-h1: clamp(2rem, 1.4rem + 2.4vw, 3.75rem);
  --space-1: 0.25rem;
  --space-2: 0.5rem;
  --space-3: 0.75rem;
  --space-4: 1rem;
  --space-5: 1.25rem;
  --space-6: 1.5rem;
  --space-8: 2rem;
  --space-10: 2.5rem;
  --page-gutter: clamp(1rem, 2.5vw, 2.75rem);
  --shell-max: 106rem;
  --control-size: 2.75rem;
  --radius: 0.5rem;
  --page: #eeeae3;
  --surface: #faf8f4;
  --surface-raised: #ffffff;
  --ink: #202e2d;
  --muted: #52615d;
  --line: #cbc8bf;
  --control-line: #77847d;
  --accent: #b93722;
  --accent-hover: #962b1a;
  --data: #136b5e;
  --data-soft: #e2eee7;
  --focus: #006a61;
  --danger: #9f2d20;
  --danger-soft: #fff0e9;
  --canvas: #102829;
  --canvas-raised: #183638;
  --canvas-ink: #f2f5ec;
  --canvas-muted: #b9cfca;
  --canvas-line: #628a83;
  --canvas-data: #8be3c7;
  --shadow: 0 0.25rem 1.25rem rgb(26 42 38 / 6%);
  --motion-fast: 160ms;
  --motion-enter: 320ms;
}

html { box-sizing: border-box; }
*, *::before, *::after { box-sizing: border-box; }

body {
  margin: 0;
  color: var(--ink);
  background: radial-gradient(ellipse at top right, #fbf8ed, transparent 65%), var(--page);
  font-family: var(--font-body);
  font-size: var(--text-body);
  line-height: 1.65;
  overflow-wrap: anywhere;
}

h1, h2, h3, p, figure, dl { margin: 0; }
h1, h2, h3 {
  font-family: var(--font-display);
  font-weight: 600;
  line-height: 1.2;
  text-wrap: balance;
}
h1 { font-size: var(--text-h1); }
h2 { font-size: var(--text-h2); }
h3 { font-size: var(--text-lg); }
small { font-size: var(--text-sm); }
p, li, dd { max-inline-size: 75ch; }
ul, ol { margin-block: var(--space-3); padding-inline-start: var(--space-6); }
li + li { margin-block-start: var(--space-2); }
dd { margin-inline-start: 0; }
a {
  color: var(--data);
  text-decoration-thickness: 0.1em;
  text-underline-offset: 0.2em;
}

button, input, select, textarea {
  min-inline-size: var(--control-size);
  min-block-size: var(--control-size);
  max-inline-size: 100%;
  border: 1px solid var(--control-line);
  border-radius: var(--radius);
  font: inherit;
}
button, select, input[type="file"] { cursor: pointer; }
button {
  padding: var(--space-2) var(--space-4);
  color: var(--ink);
  background: var(--surface-raised);
  font-weight: 600;
  line-height: 1.5;
  white-space: normal;
  overflow-wrap: anywhere;
  transition: background-color var(--motion-fast), border-color var(--motion-fast);
}
input, select, textarea {
  inline-size: 100%;
  padding: var(--space-2) var(--space-3);
  color: var(--ink);
  background: var(--surface-raised);
  line-height: 1.5;
}
input[type="number"] { font-variant-numeric: tabular-nums; }
input[type="file"] { padding: var(--space-2); font-size: var(--text-sm); }
input::file-selector-button {
  min-block-size: var(--control-size);
  margin-inline-end: var(--space-2);
  padding: var(--space-2) var(--space-3);
  border: 1px solid var(--control-line);
  border-radius: var(--radius);
  color: var(--ink);
  background: var(--surface);
  font: inherit;
  cursor: pointer;
}
textarea { resize: vertical; }
::placeholder { color: var(--muted); opacity: 1; }
:focus-visible, [tabindex="-1"]:focus {
  outline: 3px solid var(--focus);
  outline-offset: 3px;
}
[aria-invalid="true"] { border: 2px solid var(--danger); }
button:disabled, input:disabled, select:disabled, [aria-disabled="true"] {
  border-style: dashed;
  color: var(--muted);
  background: #e9e7e1;
  cursor: not-allowed;
}
[hidden] { display: none !important; }
img, video, svg { max-inline-size: 100%; block-size: auto; }
code, pre { font-family: var(--font-mono); font-size: var(--text-sm); }
pre {
  max-inline-size: 100%;
  padding: var(--space-4);
  overflow: auto;
  border: 1px solid var(--line);
  background: var(--surface);
}
.convergence-figure { max-inline-size: 48rem; margin-block: var(--space-6); }
.convergence-figure svg { display: block; inline-size: 100%; font: 16px var(--font-body); }
.convergence-figure figcaption { color: var(--muted); font-size: var(--text-sm); }
.evidence-table { overflow: auto; margin-block: var(--space-4); }
.evidence-table table { inline-size: 100%; border-collapse: collapse; min-inline-size: 36rem; }
.evidence-table caption { text-align: start; font-weight: 600; padding-block: var(--space-3); }
.evidence-table th, .evidence-table td { padding: var(--space-3); text-align: start; border-block-end: 1px solid var(--line); }

.skip-link {
  position: absolute;
  z-index: 10;
  inset-block-start: var(--space-3);
  inset-inline-start: var(--page-gutter);
  min-inline-size: var(--control-size);
  min-block-size: var(--control-size);
  padding: var(--space-2) var(--space-4);
  border: 1px solid var(--control-line);
  color: var(--ink);
  background: var(--surface-raised);
  transform: translateY(calc(-100% - 2rem));
}
.skip-link:focus { transform: none; }

.app-header, #workspace, .footer, body > footer {
  inline-size: 100%;
  max-inline-size: var(--shell-max);
  margin-inline: auto;
  padding-inline: var(--page-gutter);
}
.app-header {
  display: flex;
  flex-wrap: wrap;
  align-items: center;
  justify-content: space-between;
  gap: var(--space-3) var(--space-6);
  padding-block: var(--space-5);
  border-block-end: 1px solid var(--line);
}
.brand {
  display: inline-flex;
  flex-wrap: wrap;
  align-items: baseline;
  gap: var(--space-2);
  min-inline-size: var(--control-size);
  min-block-size: var(--control-size);
  color: var(--ink);
  font-family: var(--font-display);
  font-size: 1.75rem;
  font-weight: 700;
  line-height: 1.25;
  text-decoration: none;
}
.header-meta {
  display: flex;
  flex: 1 1 100%;
  flex-wrap: wrap;
  align-items: center;
  gap: var(--space-2) var(--space-4);
  min-inline-size: 0;
  color: var(--muted);
  font-size: var(--text-sm);
}
.header-meta a, .footer > a, body > footer > a {
  display: inline-flex;
  align-items: center;
  min-inline-size: var(--control-size);
  min-block-size: var(--control-size);
}
.header-meta label { display: grid; gap: var(--space-1); }
.version-control { display: flex; flex-wrap: wrap; align-items: center; gap: var(--space-2); min-inline-size: 0; }
#version-menu { inline-size: auto; max-inline-size: 100%; font-size: var(--text-sm); }
#workspace {
  padding-block: var(--space-8) var(--space-10);
  container-type: inline-size;
  container-name: workspace;
}
#workspace > * + * { margin-block-start: var(--space-6); }
.intro {
  display: grid;
  gap: var(--space-3);
  padding-inline-start: var(--space-4);
  border-inline-start: 3px solid var(--accent);
}
.intro h1 { max-inline-size: 25ch; }
.intro p:not(.eyebrow) { color: var(--muted); }
.eyebrow {
  color: var(--data);
  font-family: var(--font-mono);
  font-size: var(--text-sm);
  font-weight: 600;
  letter-spacing: 0.07em;
  line-height: 1.5;
  text-transform: uppercase;
}

.workspace-grid {
  display: grid;
  grid-template-columns: minmax(0, 1fr);
  align-items: start;
  gap: var(--space-4);
}
.workspace-grid > *, .form-grid > *, .metric-grid > *, .canvas-toolbar > *, .panel-heading > * {
  min-inline-size: 0;
}
.parameter-panel, .results-panel, .evidence-panel, .model-panel {
  min-inline-size: 0;
  padding: var(--space-4);
  border: 1px solid var(--line);
  border-radius: var(--radius);
  background: var(--surface);
  box-shadow: var(--shadow);
}
.parameter-panel { border-block-start: 3px solid var(--data); }
.panel-heading {
  display: flex;
  flex-wrap: wrap;
  align-items: baseline;
  justify-content: space-between;
  gap: var(--space-2) var(--space-4);
  margin-block-end: var(--space-5);
}
.panel-heading p {
  color: var(--muted);
  font-size: var(--text-body);
  line-height: 1.6;
}
.panel-heading .eyebrow, .panel-heading span, .field-hint, .field small {
  color: var(--muted);
  font-size: var(--text-sm);
  line-height: 1.6;
}
#case-form { display: grid; gap: var(--space-5); }
.parameter-panel > .field { margin-block-start: var(--space-6); padding-block-start: var(--space-5); border-block-start: 1px solid var(--line); }
fieldset { min-inline-size: 0; margin: 0; padding: 0; border: 0; }
legend { max-inline-size: 100%; margin-block-end: var(--space-3); padding: 0; font-weight: 600; }
.form-grid {
  display: grid;
  grid-template-columns: repeat(auto-fit, minmax(min(100%, 11rem), 1fr));
  align-items: start;
  gap: var(--space-4);
}
.field { display: grid; align-content: start; gap: var(--space-2); min-inline-size: 0; }
.field label { font-size: var(--text-body); font-weight: 600; line-height: 1.5; }
.field-wide { grid-column: 1 / -1; }
.buttons { display: flex; flex-wrap: wrap; align-items: stretch; gap: var(--space-2); }
.buttons > button, .buttons > a { flex: 1 1 9rem; }
.primary-button, #solve-button {
  border-color: var(--accent);
  color: #ffffff;
  background: var(--accent);
}
.secondary-button {
  border-color: var(--control-line);
  color: var(--ink);
  background: var(--surface-raised);
}
.primary-button:disabled, #solve-button:disabled, .secondary-button:disabled {
  border-color: var(--control-line);
  color: var(--muted);
  background: #e9e7e1;
}
#status, #error {
  min-inline-size: 0;
  max-inline-size: 75ch;
  padding: var(--space-3) var(--space-4);
  border: 1px solid var(--control-line);
  border-inline-start-width: 3px;
  border-radius: var(--radius);
  font-size: var(--text-body);
  line-height: 1.65;
}
#status { border-color: var(--data); color: var(--data); background: var(--data-soft); }
#error { border-color: var(--danger); color: var(--danger); background: var(--danger-soft); }
/* Collapse only empty live regions, never a runtime failure. */
#status:empty, #error:empty { padding: 0; border: 0; }
.evidence-copy-status { margin-block: var(--space-3); }
.evidence-copy-status[data-state="failed"] { color: var(--danger); font-weight: 600; }

.canvas-panel {
  min-inline-size: 0;
  border: 1px solid var(--canvas-line);
  border-radius: var(--radius);
  color: var(--canvas-ink);
  background: var(--canvas);
  box-shadow: var(--shadow);
}
.canvas-toolbar {
  display: flex;
  flex-wrap: wrap;
  align-items: center;
  justify-content: space-between;
  gap: var(--space-3) var(--space-4);
  padding: var(--space-4);
  border-block-end: 1px solid var(--canvas-line);
}
.canvas-panel .panel-heading { margin-block-end: 0; }
.canvas-panel .eyebrow, .canvas-panel .panel-heading p, .canvas-panel .panel-heading span {
  color: var(--canvas-muted);
}
.canvas-panel a { color: var(--canvas-data); }
.view-switch { display: flex; flex-wrap: wrap; gap: var(--space-2); }
.view-switch button {
  flex: 1 1 auto;
  border-color: var(--canvas-line);
  color: var(--canvas-ink);
  background: var(--canvas-raised);
  font-size: var(--text-sm);
}
.view-switch button[aria-pressed="true"], .view-switch button[aria-selected="true"] {
  border-color: var(--canvas-data);
  color: var(--canvas);
  background: var(--canvas-data);
  text-decoration: underline;
  text-decoration-thickness: 2px;
  text-underline-offset: 0.25em;
}
.canvas-panel :focus-visible { outline-color: var(--canvas-data); }
.canvas-panel #status, .canvas-panel #error { margin: var(--space-4); }

/* Decorative grid only; the solver / renderer owns all field marks. */
.canvas-stage {
  display: grid;
  min-inline-size: 0;
  min-block-size: 17.5rem;
  background-color: var(--canvas);
  background-image: linear-gradient(rgb(139 227 199 / 7%) 1px, transparent 1px),
    linear-gradient(90deg, rgb(139 227 199 / 7%) 1px, transparent 1px);
  background-size: 2rem 2rem;
}
#flow-canvas {
  display: block;
  inline-size: 100%;
  max-inline-size: 100%;
  block-size: clamp(17.5rem, 42vw, 32rem);
  min-block-size: 17.5rem;
}
.color-legend {
  display: flex;
  flex-wrap: wrap;
  align-items: center;
  justify-content: space-between;
  gap: var(--space-2) var(--space-4);
  padding: var(--space-3) var(--space-4);
  border-block-start: 1px solid var(--canvas-line);
  color: var(--canvas-muted);
  background: var(--canvas-raised);
  font-size: var(--text-sm);
  font-variant-numeric: tabular-nums;
}
.color-legend > * { min-inline-size: 0; }
#plot-description {
  max-inline-size: 75ch;
  padding: var(--space-4);
  color: var(--canvas-muted);
  font-size: var(--text-body);
  line-height: 1.65;
}
.metric-grid {
  display: grid;
  grid-template-columns: repeat(auto-fit, minmax(min(100%, 12rem), 1fr));
  gap: var(--space-3);
  margin-block: var(--space-4);
}
.metric-card {
  display: grid;
  align-content: start;
  gap: var(--space-2);
  min-inline-size: 0;
  padding: var(--space-4);
  border: 1px solid var(--line);
  border-block-start: 2px solid var(--data);
  border-radius: var(--radius);
  color: var(--ink);
  background: var(--surface-raised);
}
.metric-card dt, .metric-card h3, .metric-card p, .metric-card small, .metric-card .metric-label {
  color: var(--muted);
  font-family: var(--font-body);
  font-size: var(--text-sm);
  font-weight: 400;
  line-height: 1.6;
}
.metric-card [id^="metric-"], .metric-card dd, .metric-card strong, .metric-card output {
  color: var(--data);
  font-family: var(--font-mono);
  font-size: clamp(1.125rem, 1rem + 0.3vw, 1.375rem);
  font-weight: 600;
  font-variant-numeric: tabular-nums;
  line-height: 1.5;
  overflow-wrap: anywhere;
}
#result-summary, #convergence, .model-panel > p, .evidence-panel > p {
  max-inline-size: 75ch;
  line-height: 1.7;
}
.model-panel > * + *, .evidence-panel > * + * { margin-block-start: var(--space-3); }
.model-panel { border-inline-start: 3px solid var(--data); }
.evidence-panel { border-inline-start: 3px solid var(--accent); }
.evidence-report summary {
  min-inline-size: var(--control-size);
  min-block-size: var(--control-size);
  padding: var(--space-2) var(--space-3);
  border: 1px solid var(--control-line);
  border-radius: var(--radius);
  color: var(--data);
  background: var(--surface-raised);
  font-weight: 600;
  cursor: pointer;
}
.evidence-report[open] > * + * { margin-block-start: var(--space-3); }
.results-panel .buttons { margin-block-start: var(--space-5); }
.footer, body > footer {
  display: flex;
  flex-wrap: wrap;
  justify-content: space-between;
  align-items: baseline;
  gap: var(--space-3) var(--space-6);
  padding-block: var(--space-5) var(--space-8);
  border-block-start: 1px solid var(--line);
  color: var(--muted);
  font-size: var(--text-sm);
  line-height: 1.6;
}
#edited-at { font-variant-numeric: tabular-nums; }
noscript {
  display: block;
  margin: var(--space-4) var(--page-gutter);
  padding: var(--space-4);
  border: 2px solid var(--danger);
  color: var(--danger);
  background: var(--danger-soft);
}

/* Central width tokens: sm / md / lg / xl, retaining DOM reading order. */
@media (min-width: 36rem) {
  .header-meta { flex-basis: auto; flex-grow: 0; }
  .parameter-panel, .results-panel, .evidence-panel, .model-panel, .canvas-toolbar {
    padding: var(--space-5);
  }
  .workspace-grid { gap: var(--space-5); }
}
@media (min-width: 48rem) {
  #workspace { padding-block-start: var(--space-10); }
  .workspace-grid { gap: var(--space-6); }
  .parameter-panel .form-grid {
    grid-template-columns: repeat(auto-fit, minmax(min(100%, 12rem), 1fr));
  }
  .canvas-toolbar { padding: var(--space-5) var(--space-6); }
}
@media (min-width: 64rem) {
  .parameter-panel .form-grid {
    grid-template-columns: repeat(auto-fit, minmax(min(100%, 8.5rem), 1fr));
  }
  #flow-canvas { block-size: clamp(24rem, 38vw, 36rem); }
}
@media (min-width: 80rem) {
  .parameter-panel, .results-panel, .evidence-panel, .model-panel { padding: var(--space-6); }
  #flow-canvas { block-size: clamp(30rem, 36vw, 42rem); }
}

/* Split only when the workspace itself fits both panels, including embedded views. */
@container workspace (inline-size >= 58rem) {
  .workspace-grid { grid-template-columns: minmax(18rem, 22rem) minmax(0, 1fr); }
  .workspace-grid > :not(.parameter-panel):not(.canvas-panel) { grid-column: 1 / -1; }
}
@container workspace (inline-size >= 74rem) {
  .workspace-grid { grid-template-columns: minmax(20rem, 24rem) minmax(0, 1fr); gap: var(--space-8); }
}

@media (hover: hover) and (pointer: fine) {
  .primary-button:hover:not(:disabled), #solve-button:hover:not(:disabled) {
    border-color: var(--accent-hover);
    background: var(--accent-hover);
  }
  .secondary-button:hover:not(:disabled) { border-color: var(--data); background: var(--data-soft); }
  .view-switch button:hover:not(:disabled):not([aria-pressed="true"]):not([aria-selected="true"]) {
    border-color: var(--canvas-data);
    background: #214648;
  }
  a:hover { text-decoration-thickness: 0.15em; }
}

@keyframes workspace-enter {
  from { transform: translateY(0.375rem); }
  to { transform: none; }
}
@media (prefers-reduced-motion: no-preference) {
  .intro { animation: workspace-enter var(--motion-enter) ease-out; }
  .workspace-grid { animation: workspace-enter var(--motion-enter) 60ms ease-out backwards; }
}
@media (prefers-reduced-motion: reduce) {
  *, *::before, *::after {
    animation: none !important;
    transition: none !important;
    scroll-behavior: auto !important;
  }
}
@media (forced-colors: active) {
  :root {
    --page: Canvas;
    --surface: Canvas;
    --surface-raised: Canvas;
    --ink: CanvasText;
    --muted: CanvasText;
    --line: CanvasText;
    --control-line: ButtonText;
    --accent: ButtonText;
    --accent-hover: ButtonText;
    --data: CanvasText;
    --data-soft: Canvas;
    --focus: Highlight;
    --danger: CanvasText;
    --danger-soft: Canvas;
    --canvas: Canvas;
    --canvas-raised: Canvas;
    --canvas-ink: CanvasText;
    --canvas-muted: CanvasText;
    --canvas-line: CanvasText;
    --canvas-data: Highlight;
    --shadow: none;
  }
  body, .canvas-stage { background-image: none; }
  button, .primary-button, #solve-button, .secondary-button, .view-switch button {
    border-color: ButtonText;
    color: ButtonText;
    background: ButtonFace;
  }
  .primary-button:hover:not(:disabled), #solve-button:hover:not(:disabled),
  .secondary-button:hover:not(:disabled),
  .view-switch button:hover:not(:disabled):not([aria-pressed="true"]):not([aria-selected="true"]) {
    border-color: ButtonText;
    color: ButtonText;
    background: ButtonFace;
  }
  .view-switch button[aria-pressed="true"], .view-switch button[aria-selected="true"] {
    border-color: Highlight;
    color: HighlightText;
    background: Highlight;
  }
  button:disabled, input:disabled, select:disabled, .primary-button:disabled,
  #solve-button:disabled, .secondary-button:disabled, [aria-disabled="true"] {
    border-color: GrayText;
    color: GrayText;
    background: Canvas;
  }
  a, .canvas-panel a { color: LinkText; }
  #flow-canvas { border: 1px solid CanvasText; }
}

/* Account entry and registration/login dialog. */
.account {
  display: flex;
  align-items: center;
  gap: 8px;
  flex-wrap: wrap;
}
.account-email {
  max-width: 260px;
  overflow: hidden;
  text-overflow: ellipsis;
  white-space: nowrap;
  font-size: 14px;
  color: ButtonText;
}
.account .secondary-button {
  min-height: 36px;
  padding: 4px 12px;
  font-size: 14px;
}
#auth-dialog {
  width: min(440px, calc(100vw - 32px));
  border: 1px solid CanvasText;
  border-radius: 10px;
  padding: 20px;
  background: Canvas;
  color: CanvasText;
}
#auth-dialog::backdrop {
  background: rgb(0 0 0 / 45%);
}
.auth-form {
  display: grid;
  gap: 12px;
}
.auth-form h2 {
  margin: 0;
  font-size: 20px;
}
.auth-form p {
  margin: 0;
}
.auth-form .field {
  display: grid;
  gap: 6px;
}
.auth-form input {
  min-height: 40px;
  padding: 6px 10px;
  font: inherit;
  border: 1px solid CanvasText;
  border-radius: 6px;
  background: Field;
  color: FieldText;
}
.auth-form .buttons {
  display: flex;
  flex-wrap: wrap;
  gap: 8px;
  margin-top: 4px;
}
.auth-error {
  margin: 0;
  padding: 8px 10px;
  border: 1px solid CanvasText;
  border-radius: 6px;
  background: Canvas;
  color: CanvasText;
}