:root {
  --navy: #222C67;       /* Dark Blue: header, primary button */
  --blue: #007CBA;       /* Blue: links, hover, accents */
  --text: #2E2925;       /* Black: body text */
  --muted: #6D6E71;      /* Dark gray: supporting text */
  --white: #FFFFFF;
  --red: #D60036;        /* Errors and warnings */
  --gold: #E5B611;       /* Accent only */

  /* Supporting neutrals; these are not in the supplied palette */
  --border: #C7C9CB;
  --surface: #F5F6F8;
}

* { box-sizing: border-box; }

body {
  margin: 0;
  color: var(--text);
  font: 16px/1.5 Arial, Helvetica, sans-serif;
}

a { color: var(--blue); }
a:focus-visible,
button:focus-visible,
input:focus-visible {
  outline: 3px solid #e7a600;
  outline-offset: 2px;
}

.site-container {
  width: min(100% - 2rem, 1400px);
  margin-inline: auto;
}

.site-header { background: var(--navy); color: white; }
.site-header-inner {
  display: flex;
  align-items: center;
  justify-content: space-between;
  gap: 1.5rem;
  padding-block: 1rem;
}
.site-brand { color: white; font-size: 1.25rem; font-weight: 700; }
.site-nav { display: flex; flex-wrap: wrap; gap: 1.5rem; }
.site-nav a { color: white; }
.site-main { min-height: 75vh; padding-block: 2rem 4rem; }
.site-footer {
  padding-block: 2rem;
  border-top: 1px solid var(--border);
  background: var(--surface);
}

.model-page h1 {
  margin: 0 0 1.5rem;
  font-size: clamp(1.9rem, 3vw, 2.6rem);
  line-height: 1.2;
}

.model-grid {
  display: grid;
  grid-template-columns: minmax(360px, 500px) minmax(0, 1fr);
  gap: 1.5rem;
  align-items: start;
}

.controls-panel,
.results-panel {
  min-width: 0;
  padding: 1.5rem;
  border: 1px solid var(--border);
  background: white;
}

.controls-panel > div + div { margin-top: 1.5rem; }

.panel-title {
  margin: 0 0 1rem;
  color: var(--navy);
  font-size: 1.35rem;
}

.fields-grid,
.conditions-grid {
  display: grid;
  grid-template-columns: repeat(2, minmax(0, 1fr));
  gap: 1rem 1.25rem;
}

.fields-grid > *,
.conditions-grid > * { min-width: 0; }

.controls-panel input[type="number"] {
  min-height: 38px;
  padding: 0.4rem 0.6rem;
  border: 1px solid #aebbc5;
  border-radius: 3px;
  color: var(--text);
}

.controls-panel input:disabled {
  background: var(--surface);
  color: var(--muted);
}

#calculate {
  padding: 0.65rem 1.5rem;
  border: 1px solid var(--navy);
  border-radius: 3px;
  background: var(--navy);
  color: white;
  font: inherit;
  font-weight: 700;
  cursor: pointer;
}

#calculate:hover { background: var(--blue); }

.results-description {
  max-width: 75ch;
  margin: 1.25rem 0 0;
  color: var(--muted);
}

@media (max-width: 1050px) {
  .model-grid { grid-template-columns: 1fr; }
}

@media (max-width: 600px) {
  .site-header-inner { align-items: flex-start; flex-direction: column; }
  .controls-panel, .results-panel { padding: 1rem; }
  .fields-grid, .conditions-grid { grid-template-columns: 1fr; }
  #mm0_chart { height: 450px !important; }
}}

.section-header {
  margin: 0 0 0.75rem;
  padding-bottom: 0.35rem;
  border-bottom: 2px solid var(--border);
  color: var(--navy);
  font-size: 20px;
}

.calculate-row {
  margin-top: 1.25rem;
  text-align: center;
}

/* Compact the left panel */
.controls-panel {
  padding: 1rem;
}

.controls-panel > div + div {
  margin-top: 0.75rem;
}

.controls-panel .section-header {
  margin-bottom: 0.4rem;
  padding-bottom: 0.2rem;
}

.controls-panel .fields-grid,
.controls-panel .conditions-grid {
  gap: 0.5rem 1rem;
}

.controls-panel input[type="number"] {
  min-height: 32px;
  padding: 0.25rem 0.5rem;
}

.controls-panel .calculate-row {
  margin-top: 0.75rem;
}

.model-grid {
  grid-template-columns: minmax(0, 570px) minmax(0, 1fr);
}

/* Stack the panels before the graph becomes too narrow. */
@media (max-width: 1200px) {
  .model-grid {
    grid-template-columns: 1fr;
  }
}

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

.controls-panel > div + div {
  margin-top: 0.75rem;
}

.controls-panel .section-header {
  margin-bottom: 0.3rem;
  padding-bottom: 0.15rem;
}

.controls-panel .fields-grid,
.controls-panel .conditions-grid {
  row-gap: 0.35rem;
}

/* Align both headings and reduce space above them */
.controls-panel,
.results-panel {
  padding: 0.75rem 1rem 1rem;
}

.controls-panel .section-header,
.results-panel .panel-title {
  margin-top: 0;
  line-height: 1.3;
}

/* Bring the condition controls closer to Solutes */
.controls-panel > .conditions-grid {
  margin-top: 0.6rem;
}

.controls-panel > div:first-child .section-header {
  font-size: 1.35rem;
}
#calculate:hover {
  background: var(--blue);
}

#solute_calculate_warning {
  color: var(--red);
}

a:focus-visible,
button:focus-visible,
input:focus-visible {
  outline: 3px solid var(--navy);
  outline-offset: 2px;
}

.controls-panel .section-header {
  border-bottom-color: var(--blue);
}

.site-main {
  min-height: 0;
  padding-bottom: 1.5rem;
}

.fda-logo {
    display: block;
    width: 300px;
    max-width: 100%;
    height: auto;
}

/* Let the header use the full screen width, despite .site-container. */
.site-container.site-header-inner {
    max-width: none;
    width: 100%;
    margin: 0;
    padding: 14px 16px;
    box-sizing: border-box;

    display: grid;
    grid-template-columns: 1fr auto 1fr;
    align-items: center;
    gap: 16px;
}

.site-header-inner .site-brand {
    justify-self: start;
}

.fda-logo {
    display: block;
    width: 260px;
    height: auto;
}

.site-tool-title {
    justify-self: center;
    color: #fff;
    font-size: 1.5rem;
    font-weight: 600;
    text-align: center;
}

.site-header-inner .site-nav {
    justify-self: end;
}

@media (max-width: 1100px) {
    .site-container.site-header-inner {
        grid-template-columns: 1fr auto;
    }

    .site-tool-title {
        grid-column: 1 / -1;
        grid-row: 2;
    }
}

.polymer-section > h3,
.results-panel > h3 {
    font-size: 20px !important;
    line-height: 1.3 !important;
    margin-top: 0 !important;
    margin-bottom: 10px !important;
}

.site-main {
    padding: 20px 24px;
    box-sizing: border-box;
}