/* ---------------------------------------------------
   Peptide Calculator Lab — base styles
   Theme: Lab Notebook — aged paper, graph-paper grid,
   blue-black ink, red-pen annotation for results & flags.
--------------------------------------------------- */

:root {
  --bg: #f1ead4;
  --bg-alt: #e8dcbc;
  --card: #f8f2df;
  --paper: #fdf9ec;
  --card-border: #cdbf98;
  --text: #202c49;
  --text-dim: #4f5a7c;
  --text-faint: #838aa5;
  --accent: #202c49;
  --accent-dim: #10182e;
  --accent-soft: rgba(32, 44, 73, 0.07);
  --danger: #9c3226;
  --danger-soft: rgba(156, 50, 38, 0.08);
  --danger-border: rgba(156, 50, 38, 0.35);
  --radius: 4px;
  --max-width: 880px;
  --font: Charter, "Iowan Old Style", Georgia, "Times New Roman", serif;
  --font-display: "Courier New", ui-monospace, SFMono-Regular, Menlo, monospace;
}

* {
  box-sizing: border-box;
}

html {
  scroll-behavior: smooth;
}

body {
  margin: 0;
  font-family: var(--font);
  background: var(--bg);
  color: var(--text);
  line-height: 1.6;
  -webkit-font-smoothing: antialiased;
}

a {
  color: var(--accent);
  text-decoration: none;
}

a:hover {
  text-decoration: underline;
}

img {
  max-width: 100%;
  display: block;
}

.container {
  max-width: var(--max-width);
  margin: 0 auto;
  padding: 0 20px;
}

/* ---------------- Header ---------------- */

.site-header {
  position: sticky;
  top: 0;
  z-index: 50;
  background: rgba(241, 234, 212, 0.9);
  backdrop-filter: blur(10px);
  border-bottom: 1px solid var(--card-border);
}

.header-inner {
  display: flex;
  align-items: center;
  justify-content: space-between;
  padding: 16px 20px;
  max-width: var(--max-width);
  margin: 0 auto;
}

.brand {
  display: flex;
  align-items: center;
  gap: 10px;
  font-family: var(--font-display);
  font-weight: 700;
  font-size: 17px;
  letter-spacing: 0;
  color: var(--text);
}

.brand svg {
  flex-shrink: 0;
}

.brand-name span {
  color: var(--accent);
}

.header-nav {
  display: flex;
  gap: 24px;
  font-family: var(--font-display);
}

.header-nav a {
  color: var(--text-dim);
  font-size: 13px;
  font-weight: 700;
}

.header-nav a:hover {
  color: var(--text);
  text-decoration: none;
}

/* ---------------- Mobile nav (details/summary, no JS required) ---------------- */

.mobile-nav {
  display: none;
  position: relative;
}

.mobile-nav summary {
  list-style: none;
  cursor: pointer;
  color: var(--text-dim);
  font-family: var(--font-display);
  font-size: 12.5px;
  font-weight: 700;
  padding: 8px 14px;
  border: 1px solid var(--card-border);
  border-radius: 3px;
}

.mobile-nav summary::-webkit-details-marker {
  display: none;
}

.mobile-nav[open] summary {
  color: var(--accent);
  border-color: var(--accent);
}

.mobile-nav > nav {
  position: absolute;
  right: 0;
  top: calc(100% + 8px);
  background: var(--card);
  border: 1px solid var(--card-border);
  border-radius: 4px;
  padding: 10px;
  min-width: 240px;
  box-shadow: 0 16px 32px -10px rgba(32, 44, 73, 0.25);
  z-index: 60;
}

.mobile-nav > nav a {
  display: block;
  padding: 9px 10px;
  border-radius: 3px;
  color: var(--text-dim);
  font-family: var(--font-display);
  font-size: 13px;
}

.mobile-nav > nav a:hover {
  background: var(--accent-soft);
  color: var(--accent);
  text-decoration: none;
}

/* ---------------- Breadcrumb ---------------- */

.breadcrumb {
  padding: 14px 20px 0;
}

.breadcrumb ol {
  max-width: var(--max-width);
  margin: 0 auto;
  padding: 0;
  list-style: none;
  display: flex;
  flex-wrap: wrap;
  gap: 4px;
  font-family: var(--font-display);
  font-size: 12px;
  color: var(--text-faint);
}

.breadcrumb li {
  display: flex;
  align-items: center;
  gap: 4px;
}

.breadcrumb li:not(:last-child)::after {
  content: "/";
  margin-left: 4px;
  color: var(--text-faint);
}

.breadcrumb a {
  color: var(--text-dim);
}

.breadcrumb a:hover {
  color: var(--accent);
}

.breadcrumb li[aria-current] {
  color: var(--text-faint);
}

/* ---------------- Tool grid (homepage) ---------------- */

.tool-grid {
  display: grid;
  grid-template-columns: repeat(2, 1fr);
  gap: 20px;
  margin-top: 8px;
}

.tool-card {
  background: var(--card);
  border: 1px solid var(--card-border);
  border-radius: var(--radius);
  padding: 24px;
  transition: border-color 0.15s ease, transform 0.15s ease;
}

.tool-card:hover {
  border-color: var(--accent);
  transform: translateY(-2px);
}

.tool-card h3 {
  margin: 0 0 8px;
  font-family: var(--font-display);
  font-size: 15.5px;
}

.tool-card h3 a {
  color: var(--text);
}

.tool-card h3 a:hover {
  color: var(--accent);
  text-decoration: none;
}

.tool-card p {
  margin: 0 0 14px;
  color: var(--text-dim);
  font-size: 14px;
}

.tool-card .tool-link {
  font-family: var(--font-display);
  font-size: 12.5px;
  font-weight: 700;
  color: var(--accent);
}

.tool-card .tool-preview {
  display: block;
  font-family: var(--font-display);
  font-variant-numeric: tabular-nums;
  font-size: 12px;
  color: var(--text-dim);
  background: var(--paper);
  border: 1px solid var(--card-border);
  border-radius: 3px;
  padding: 6px 10px;
  margin: 0 0 12px;
}

/* ---------------- Related tools ---------------- */

.related-tools {
  display: flex;
  flex-wrap: wrap;
  gap: 10px;
  margin: 10px 0 0;
  padding: 0;
  list-style: none;
}

.related-tools a {
  display: inline-block;
  padding: 8px 16px;
  border: 1px solid var(--card-border);
  border-radius: 3px;
  font-family: var(--font-display);
  font-size: 12.5px;
  color: var(--text-dim);
}

.related-tools a:hover {
  border-color: var(--accent);
  color: var(--accent);
  text-decoration: none;
}

/* ---------------- Mode toggle (segmented, e.g. "solve for" selection) ---------------- */

.mode-toggle {
  display: flex;
  border: 1px solid var(--card-border);
  border-radius: 5px;
  padding: 4px;
  gap: 4px;
  margin-bottom: 22px;
}

.mode-toggle button {
  flex: 1;
  border: none;
  background: transparent;
  color: var(--text-dim);
  font-size: 12px;
  font-weight: 700;
  padding: 10px 8px;
  border-radius: 3px;
  cursor: pointer;
  font-family: var(--font-display);
  transition: all 0.15s ease;
}

.mode-toggle button.active {
  background: var(--accent);
  color: var(--paper);
}

/* ---------------- Buttons ---------------- */

.btn {
  display: inline-block;
  background: var(--accent);
  color: var(--paper);
  font-family: var(--font-display);
  font-weight: 700;
  padding: 12px 24px;
  border-radius: 3px;
  font-size: 13.5px;
}

.btn:hover {
  text-decoration: none;
  opacity: 0.9;
}

/* ---------------- Calculator suite (tabs, presets, vial, breakdown) ---------------- */

.calc-tabs {
  display: flex;
  flex-wrap: wrap;
  gap: 4px;
  margin-bottom: 26px;
  border-bottom: 1px solid var(--card-border);
}

.calc-tab {
  background: transparent;
  border: 1px solid transparent;
  border-bottom: none;
  color: var(--text-dim);
  font-family: var(--font-display);
  font-size: 12.5px;
  font-weight: 700;
  padding: 10px 14px;
  border-radius: 3px 3px 0 0;
  margin-bottom: -1px;
  cursor: pointer;
}

.calc-tab:hover {
  color: var(--text);
}

.calc-tab.active {
  color: var(--text);
  background: var(--card);
  border-color: var(--card-border);
  border-bottom-color: var(--card);
}

.calc-tab:focus-visible {
  outline: 2px solid var(--accent);
  outline-offset: 2px;
}

.calc-panel[hidden] {
  display: none;
}

.field-columns {
  display: grid;
  grid-template-columns: repeat(3, minmax(0, 1fr));
  gap: 22px;
  align-items: start;
}

.preset-grid {
  display: flex;
  flex-wrap: wrap;
  align-content: flex-start;
  gap: 6px;
  margin: 10px 0;
}

.preset-btn {
  border: 1px solid var(--card-border);
  background: var(--paper);
  color: var(--text-dim);
  font-family: var(--font-display);
  font-size: 11.5px;
  font-weight: 700;
  padding: 6px 10px;
  border-radius: 3px;
  cursor: pointer;
}

.preset-btn:hover {
  border-color: var(--accent);
  color: var(--text);
}

.preset-btn.active {
  background: var(--accent);
  border: 2px solid var(--accent);
  color: var(--paper);
  padding: 5px 9px;
}

.preset-btn:focus-visible {
  outline: 2px solid var(--accent);
  outline-offset: 1px;
}

.sub-toggle-row {
  margin-bottom: 20px;
}

.result-hero-row {
  display: grid;
  grid-template-columns: repeat(auto-fit, minmax(200px, 1fr));
  gap: 24px;
}

.result-list {
  display: grid;
  grid-template-columns: repeat(2, 1fr);
  gap: 10px 24px;
  margin-top: 18px;
  padding-top: 18px;
  border-top: 1px solid var(--card-border);
  text-align: left;
}

.result-list-item {
  display: flex;
  justify-content: space-between;
  gap: 10px;
  font-family: var(--font-display);
  font-size: 12.5px;
}

.result-list-item .rli-label {
  color: var(--text-dim);
}

.result-list-item .rli-value {
  color: var(--text);
  font-weight: 700;
  font-variant-numeric: tabular-nums;
  text-align: right;
}

.vial-visual {
  margin-top: 24px;
}

.vial-header {
  display: flex;
  justify-content: space-between;
  align-items: baseline;
  margin-bottom: 8px;
  font-family: var(--font-display);
}

.vial-title {
  font-weight: 700;
  color: var(--text);
  text-transform: uppercase;
  letter-spacing: 0.5px;
  font-size: 11px;
}

.vial-total {
  color: var(--text-dim);
  font-size: 12px;
  font-variant-numeric: tabular-nums;
}

.vial-bar {
  display: flex;
  height: 26px;
  border: 1px solid var(--card-border);
  border-radius: 3px;
  overflow: hidden;
  background: var(--paper);
}

.vial-segment {
  height: 100%;
  min-width: 2px;
  transition: width 0.2s ease;
}

.vial-segment--a {
  background: var(--danger);
}

.vial-segment--b {
  background: rgba(32, 44, 73, 0.18);
}

.vial-legend {
  display: flex;
  gap: 20px;
  flex-wrap: wrap;
  margin-top: 10px;
  font-family: var(--font-display);
  font-size: 12px;
  color: var(--text-dim);
}

.legend-item {
  display: flex;
  align-items: center;
  gap: 6px;
}

.legend-swatch {
  width: 10px;
  height: 10px;
  border-radius: 2px;
  flex-shrink: 0;
}

.legend-swatch--a {
  background: var(--danger);
}

.legend-swatch--b {
  background: rgba(32, 44, 73, 0.18);
  border: 1px solid var(--card-border);
}

.calc-controls {
  display: flex;
  flex-wrap: wrap;
  gap: 10px;
  margin-top: 26px;
}

.ctrl-btn {
  font-family: var(--font-display);
  font-size: 12px;
  font-weight: 700;
  color: var(--text-dim);
  background: var(--paper);
  border: 1px solid var(--card-border);
  border-radius: 3px;
  padding: 9px 16px;
  cursor: pointer;
}

.ctrl-btn:hover {
  border-color: var(--accent);
  color: var(--text);
}

.ctrl-btn:focus-visible {
  outline: 2px solid var(--accent);
  outline-offset: 2px;
}

.copy-status {
  margin-top: 8px;
  font-size: 12px;
  color: var(--danger);
  min-height: 16px;
}

.breakdown {
  margin-top: 20px;
  border: 1px solid var(--card-border);
  border-radius: var(--radius);
  background: var(--card);
  padding: 4px 20px;
}

.breakdown summary {
  cursor: pointer;
  padding: 14px 0;
  font-family: var(--font-display);
  font-weight: 700;
  font-size: 13px;
  color: var(--text);
  list-style: none;
}

.breakdown summary::-webkit-details-marker {
  display: none;
}

.breakdown summary::before {
  content: "▸ ";
  color: var(--danger);
}

.breakdown[open] summary::before {
  content: "▾ ";
}

.breakdown-step {
  padding: 12px 0;
  border-top: 1px solid var(--card-border);
}

.breakdown-step:first-of-type {
  border-top: none;
  padding-top: 0 0 12px;
}

.breakdown-step .bs-label {
  color: var(--text-dim);
  text-transform: uppercase;
  font-family: var(--font-display);
  font-size: 10.5px;
  letter-spacing: 0.5px;
  margin-bottom: 4px;
}

.breakdown-step .bs-formula {
  color: var(--text);
  font-family: var(--font-display);
  font-variant-numeric: tabular-nums;
  font-size: 13px;
}

@media (max-width: 760px) {
  .field-columns {
    grid-template-columns: 1fr;
    gap: 16px;
  }

  /* Once fields stack vertically, matching label-area heights
     across columns is no longer necessary. */
  .field-label-row {
    min-height: 0;
  }
}

@media (max-width: 640px) {
  .result-list {
    grid-template-columns: 1fr;
  }
}

@media print {
  .site-header,
  .mobile-nav,
  .breadcrumb,
  .site-footer,
  .calc-tabs,
  .calc-controls,
  .hero,
  .tool-grid,
  .content-section {
    display: none !important;
  }

  .calc-card {
    box-shadow: none;
    border: 1px solid #999;
  }
}

/* ---------------- Hero ---------------- */

.hero {
  padding: 64px 20px 40px;
  text-align: center;
  background-image:
    linear-gradient(rgba(32, 44, 73, 0.055) 1px, transparent 1px),
    linear-gradient(90deg, rgba(32, 44, 73, 0.055) 1px, transparent 1px);
  background-size: 26px 26px;
}

.eyebrow {
  display: inline-block;
  font-family: var(--font-display);
  font-size: 11.5px;
  font-weight: 700;
  letter-spacing: 1.5px;
  text-transform: uppercase;
  color: var(--danger);
  background: var(--danger-soft);
  border: 1px solid var(--danger-border);
  padding: 6px 14px;
  border-radius: 3px;
  margin-bottom: 20px;
}

.hero h1 {
  font-family: var(--font-display);
  font-size: clamp(26px, 4.6vw, 40px);
  line-height: 1.2;
  margin: 0 0 16px;
  font-weight: 700;
  letter-spacing: 0;
}

.hero p.lead {
  max-width: 620px;
  margin: 0 auto;
  color: var(--text-dim);
  font-size: 17px;
}

.hero-trust {
  display: flex;
  flex-wrap: wrap;
  justify-content: center;
  gap: 10px 22px;
  margin-top: 22px;
  font-family: var(--font-display);
  font-size: 12.5px;
  font-weight: 700;
  color: var(--text-dim);
}

.hero-trust-item {
  display: flex;
  align-items: center;
  gap: 6px;
}

.hero-trust-item::before {
  content: "✓";
  color: var(--danger);
  font-weight: 700;
}

/* ---------------- Calculator Card ---------------- */

.calc-section {
  padding: 24px 20px 60px;
}

.calc-card {
  background: var(--card);
  border: 1px solid var(--card-border);
  border-radius: var(--radius);
  padding: 32px;
  box-shadow: 0 16px 40px -22px rgba(32, 44, 73, 0.3);
}

.calc-card h2 {
  margin: 0 0 24px;
  font-family: var(--font-display);
  font-size: 18px;
  font-weight: 700;
  display: flex;
  align-items: center;
  gap: 10px;
}

.calc-card h2::before {
  content: "";
  width: 8px;
  height: 8px;
  border-radius: 50%;
  background: var(--danger);
  flex-shrink: 0;
}

.field-group {
  margin-bottom: 22px;
  min-width: 0;
}

.field-label-row {
  display: flex;
  flex-direction: column;
  align-items: flex-start;
  justify-content: flex-start;
  gap: 6px;
  margin-bottom: 8px;
  min-height: 66px;
}

.field-label {
  display: block;
  min-width: 0;
  font-family: var(--font-display);
  font-size: 12px;
  font-weight: 700;
  color: var(--text-dim);
  text-transform: uppercase;
  letter-spacing: 0.4px;
  line-height: 1.4;
}

.field-input {
  width: 100%;
  min-width: 0;
  background: var(--paper);
  border: 1px solid var(--card-border);
  border-radius: 3px;
  padding: 14px 16px;
  font-size: 17px;
  color: var(--text);
  font-family: var(--font-display);
  font-variant-numeric: tabular-nums;
  transition: border-color 0.15s ease, box-shadow 0.15s ease;
}

.field-input:focus {
  outline: none;
  border-color: var(--accent);
  box-shadow: 0 0 0 3px var(--accent-soft);
}

.field-input::placeholder {
  color: var(--text-faint);
}

.field-hint {
  margin: 8px 0 0;
  font-size: 12.5px;
  color: var(--text-faint);
}

.field-error {
  min-height: 20px;
  margin-top: 4px;
  font-size: 12.5px;
  font-weight: 700;
  color: var(--danger);
}

.field-input.input-error {
  border-color: var(--danger);
  box-shadow: 0 0 0 3px var(--danger-soft);
}

.calc-intro {
  color: var(--text-dim);
  font-size: 15px;
  margin: 0 0 28px;
}

.unit-toggle {
  display: inline-flex;
  flex-shrink: 0;
  border: 1px solid var(--card-border);
  border-radius: 4px;
  padding: 3px;
  gap: 2px;
}

.unit-toggle button {
  border: none;
  background: transparent;
  color: var(--text-dim);
  font-size: 12px;
  font-weight: 700;
  padding: 5px 14px;
  border-radius: 2px;
  cursor: pointer;
  font-family: var(--font-display);
  transition: all 0.15s ease;
}

.unit-toggle button.active {
  background: var(--accent);
  color: var(--paper);
}

/* ---------------- Result ---------------- */

.result-box {
  margin-top: 28px;
  background-color: var(--paper);
  background-image:
    linear-gradient(rgba(32, 44, 73, 0.07) 1px, transparent 1px),
    linear-gradient(90deg, rgba(32, 44, 73, 0.07) 1px, transparent 1px);
  background-size: 16px 16px;
  border: 1px solid var(--card-border);
  border-radius: var(--radius);
  padding: 28px;
  text-align: center;
}

.result-group {
  padding: 8px 0;
}

.result-divider {
  height: 1px;
  background: var(--card-border);
  margin: 18px 0;
}

.result-caption {
  font-family: var(--font-display);
  font-size: 11.5px;
  font-weight: 700;
  letter-spacing: 1px;
  text-transform: uppercase;
  color: var(--text-dim);
  margin-bottom: 6px;
}

.result-value {
  font-family: var(--font-display);
  font-variant-numeric: tabular-nums;
  font-size: 36px;
  font-weight: 700;
  color: var(--danger);
  letter-spacing: 0;
}

.result-value .unit {
  font-size: 17px;
  font-weight: 700;
  color: var(--text-dim);
  margin-left: 4px;
}

.result-secondary {
  margin-top: 8px;
  font-family: var(--font-display);
  font-variant-numeric: tabular-nums;
  font-size: 13.5px;
  color: var(--text-faint);
}

.result-secondary strong {
  color: var(--text-dim);
}

.calc-note {
  margin-top: 18px;
  font-size: 12.5px;
  color: var(--text-faint);
  text-align: center;
  line-height: 1.5;
}

.warning-banner {
  margin-top: 18px;
  border: 1px solid var(--danger-border);
  background: var(--danger-soft);
  color: var(--danger);
  border-radius: 3px;
  padding: 12px 16px;
  font-size: 13.5px;
  display: none;
}

.warning-banner.visible {
  display: block;
}

/* ---------------- SEO content ---------------- */

.content-section {
  padding: 20px 20px 80px;
}

.content-inner {
  max-width: 720px;
  margin: 0 auto;
}

.content-inner h2 {
  font-family: var(--font-display);
  font-size: 20px;
  font-weight: 700;
  margin: 48px 0 14px;
  color: var(--text);
}

.content-inner h2:first-child {
  margin-top: 0;
}

.content-inner h3 {
  font-family: var(--font-display);
  font-size: 15.5px;
  font-weight: 700;
  margin: 28px 0 10px;
  color: var(--accent);
}

.content-inner p {
  color: var(--text-dim);
  font-size: 15.5px;
  margin: 0 0 16px;
}

.content-inner ul {
  margin: 0 0 16px;
  padding-left: 20px;
  color: var(--text-dim);
  font-size: 15.5px;
}

.content-inner ul li {
  margin-bottom: 8px;
}

.content-inner ul li:last-child {
  margin-bottom: 0;
}

.review-date-placeholder {
  color: var(--danger);
  font-style: italic;
}

.content-inner table {
  width: 100%;
  border-collapse: collapse;
  margin: 0 0 20px;
  font-family: var(--font-display);
  font-size: 13.5px;
  display: block;
  overflow-x: auto;
}

.content-inner th,
.content-inner td {
  text-align: left;
  padding: 10px 14px;
  border-bottom: 1px solid var(--card-border);
  color: var(--text-dim);
  white-space: nowrap;
}

.content-inner th {
  color: var(--text);
  font-size: 11px;
  text-transform: uppercase;
  letter-spacing: 0.5px;
}

.step-list {
  background: var(--card);
  border: 1px solid var(--card-border);
  border-radius: var(--radius);
  padding: 22px 26px;
  margin: 20px 0;
  font-family: var(--font-display);
  font-variant-numeric: tabular-nums;
}

.step-list p {
  margin-bottom: 14px;
  font-size: 14.5px;
}

.step-list p:last-child {
  margin-bottom: 0;
}

.step-list strong {
  color: var(--text);
}

.example-actions {
  margin: 20px 0;
}

.capability-grid {
  display: grid;
  grid-template-columns: repeat(2, 1fr);
  gap: 20px;
  margin: 20px 0;
}

.capability-card {
  background: var(--card);
  border: 1px solid var(--card-border);
  border-radius: var(--radius);
  padding: 22px 24px;
}

.capability-card h3 {
  margin-top: 0;
}

.guide-pending {
  color: var(--text-faint);
  font-style: italic;
  font-size: 0.9em;
}

@media (max-width: 640px) {
  .capability-grid {
    grid-template-columns: 1fr;
  }
}

.faq-item {
  border-bottom: 1px solid var(--card-border);
  padding: 18px 0;
}

.faq-item:last-child {
  border-bottom: none;
}

.faq-item h3 {
  margin: 0 0 8px;
  font-family: var(--font-display);
  font-size: 14.5px;
}

.faq-item p {
  margin: 0;
  font-size: 14.5px;
}

.disclaimer-box {
  background: var(--card);
  border: 1px solid var(--card-border);
  border-left: 3px solid var(--danger);
  border-radius: 3px;
  padding: 18px 20px;
  font-size: 13.5px;
  color: var(--text-faint);
  margin-top: 30px;
}

.disclaimer-box strong {
  color: var(--text-dim);
}

/* ---------------- Footer ---------------- */

.site-footer {
  border-top: 1px solid var(--card-border);
  padding: 40px 20px 30px;
  background: var(--bg-alt);
}

.footer-inner {
  max-width: var(--max-width);
  margin: 0 auto;
  display: flex;
  flex-wrap: wrap;
  justify-content: space-between;
  gap: 24px;
}

.footer-brand {
  max-width: 380px;
}

.footer-brand .brand {
  margin-bottom: 10px;
}

.footer-brand p {
  color: var(--text-faint);
  font-size: 13px;
  margin: 0;
}

.footer-links {
  display: flex;
  gap: 44px;
  flex-wrap: wrap;
}

.footer-col h4 {
  font-family: var(--font-display);
  font-size: 11.5px;
  text-transform: uppercase;
  letter-spacing: 0.8px;
  color: var(--text-faint);
  margin: 0 0 12px;
}

.footer-col a {
  display: block;
  font-family: var(--font-display);
  color: var(--text-dim);
  font-size: 13px;
  margin-bottom: 8px;
}

.footer-col a:hover {
  color: var(--accent);
  text-decoration: none;
}

.footer-bottom {
  max-width: var(--max-width);
  margin: 30px auto 0;
  padding-top: 20px;
  border-top: 1px solid var(--card-border);
  font-family: var(--font-display);
  font-size: 12px;
  color: var(--text-faint);
  text-align: center;
}

/* ---------------- Responsive ---------------- */

@media (max-width: 640px) {
  .header-nav {
    display: none;
  }

  .mobile-nav {
    display: block;
  }

  .calc-card {
    padding: 22px;
  }

  .result-value {
    font-size: 30px;
  }

  .hero {
    padding: 44px 20px 30px;
  }

  .tool-grid {
    grid-template-columns: 1fr;
  }

  .mode-toggle {
    flex-direction: column;
  }
}