/* ===== Design Tokens ===== */
:root {
  --colour-teal: #3B8284;
  --colour-coral: #FD7A7F;
  --colour-navy: #26588D;
  --colour-dark: #2A3439;
  --colour-white: #FFFFFF;
  --colour-light-grey: #F4F5F6;
  --colour-mid-grey: #D1D5DB;
  --colour-border: #E2E5E9;
  --radius: 6px;
  --shadow: 0 1px 3px rgba(42, 52, 57, 0.1);
}

/* ===== Reset & Base ===== */
*, *::before, *::after { box-sizing: border-box; margin: 0; padding: 0; }

html { font-size: 16px; -webkit-text-size-adjust: 100%; }

body {
  font-family: Roboto, arial, sans-serif;
  color: var(--colour-dark);
  background: var(--colour-light-grey);
  line-height: 1.6;
  min-height: 100vh;
}

h1, h2, h3, h4,
.btn,
.section-heading,
.tab-btn,
.methodology-summary {
  font-family: Montserrat, sans-serif;
}

/* ===== Layout ===== */
.container {
  max-width: 1100px;
  margin: 0 auto;
  padding: 1.5rem 1rem;
}

header {
  text-align: center;
  margin-bottom: 2rem;
}

header h1 {
  font-size: 1.5rem;
  color: var(--colour-navy);
  margin-bottom: 0.25rem;
}

header p {
  font-size: 0.9rem;
  color: var(--colour-dark);
  opacity: 0.7;
}

/* ===== Cards ===== */
.card {
  background: var(--colour-white);
  border: 1px solid var(--colour-border);
  border-radius: var(--radius);
  box-shadow: var(--shadow);
  padding: 1.5rem;
  margin-bottom: 1.5rem;
}

.card h2 {
  font-size: 1.1rem;
  color: var(--colour-navy);
  margin-bottom: 1rem;
}

/* ===== Tabs ===== */
.tabs {
  display: flex;
  border-bottom: 2px solid var(--colour-border);
  margin-bottom: 1.25rem;
}

.tab-btn {
  flex: 1;
  padding: 0.6rem 1rem;
  background: none;
  border: none;
  border-bottom: 2px solid transparent;
  margin-bottom: -2px;
  font-size: 0.95rem;
  font-weight: 600;
  color: var(--colour-dark);
  opacity: 0.5;
  cursor: pointer;
  transition: opacity 0.15s, border-color 0.15s;
}

.tab-btn:hover { opacity: 0.8; }

.tab-btn.active {
  opacity: 1;
  color: var(--colour-teal);
  border-bottom-color: var(--colour-teal);
}

.tab-panel { display: none; }
.tab-panel.active { display: block; }

/* ===== Forms ===== */
label {
  display: block;
  font-size: 0.85rem;
  font-weight: 600;
  margin-bottom: 0.25rem;
  color: var(--colour-dark);
}

input[type="text"],
input[type="password"],
input[type="number"],
input[type="file"] {
  width: 100%;
  padding: 0.55rem 0.75rem;
  font-size: 0.95rem;
  border: 1px solid var(--colour-mid-grey);
  border-radius: var(--radius);
  background: var(--colour-white);
  color: var(--colour-dark);
  transition: border-color 0.15s;
}

input:focus {
  outline: none;
  border-color: var(--colour-teal);
  box-shadow: 0 0 0 2px rgba(59, 130, 132, 0.15);
}

.form-group { margin-bottom: 1rem; }

.form-row {
  display: grid;
  grid-template-columns: 1fr 1fr;
  gap: 1rem;
}

.form-hint {
  font-size: 0.8rem;
  color: var(--colour-dark);
  opacity: 0.6;
  margin-top: 0.2rem;
}

/* ===== Buttons ===== */
.btn {
  display: inline-flex;
  align-items: center;
  justify-content: center;
  padding: 0.6rem 1.5rem;
  font-size: 0.95rem;
  font-weight: 600;
  border: none;
  border-radius: var(--radius);
  cursor: pointer;
  transition: background 0.15s, opacity 0.15s;
}

.btn:disabled {
  opacity: 0.5;
  cursor: not-allowed;
}

.btn-primary {
  background: var(--colour-teal);
  color: var(--colour-white);
}

.btn-primary:hover:not(:disabled) {
  background: #327072;
}

.btn-full { width: 100%; }

/* ===== Status & Messages ===== */
.status-area {
  margin-top: 1rem;
}

.status-msg {
  padding: 0.75rem 1rem;
  border-radius: var(--radius);
  font-size: 0.9rem;
  margin-bottom: 0.75rem;
}

.status-msg.info {
  background: #EBF5FB;
  color: var(--colour-navy);
  border: 1px solid #BDD8EC;
}

.status-msg.success {
  background: #E8F5E9;
  color: #2E7D32;
  border: 1px solid #A5D6A7;
}

.status-msg.warning {
  background: #FFF8E1;
  color: #F57F17;
  border: 1px solid #FFE082;
}

.status-msg.error {
  background: #FDECEA;
  color: #C62828;
  border: 1px solid #F5C6CB;
}

#unusual-result-panel {
  border-left: 4px solid var(--colour-teal);
}

/* ===== Progress ===== */
.progress-area {
  margin-top: 1rem;
}

.progress-bar-wrap {
  height: 6px;
  background: var(--colour-border);
  border-radius: 3px;
  overflow: hidden;
  margin-top: 0.5rem;
}

.progress-bar-fill {
  height: 100%;
  background: var(--colour-teal);
  width: 0%;
  transition: width 0.3s;
}

.progress-text {
  font-size: 0.85rem;
  color: var(--colour-dark);
  opacity: 0.7;
}

/* ===== Gas Unit Check ===== */
.gas-check {
  background: var(--colour-light-grey);
  border: 1px solid var(--colour-border);
  border-radius: var(--radius);
  padding: 1rem;
  margin-top: 1rem;
}

.gas-check p { font-size: 0.9rem; margin-bottom: 0.5rem; }

.gas-check .costs {
  font-weight: 600;
  font-size: 1rem;
  color: var(--colour-navy);
}

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

.toggle-wrap input[type="checkbox"] {
  width: auto;
  accent-color: var(--colour-teal);
}

.toggle-wrap label {
  font-weight: 400;
  margin-bottom: 0;
}

/* ===== Property Selection ===== */
.property-list {
  list-style: none;
}

.property-list li {
  padding: 0.6rem 0.75rem;
  border: 1px solid var(--colour-border);
  border-radius: var(--radius);
  margin-bottom: 0.5rem;
  cursor: pointer;
  display: flex;
  align-items: center;
  gap: 0.5rem;
  transition: border-color 0.15s, background 0.15s;
}

.property-list li:hover {
  border-color: var(--colour-teal);
  background: rgba(59, 130, 132, 0.04);
}

.property-list li.selected {
  border-color: var(--colour-teal);
  background: rgba(59, 130, 132, 0.08);
}

.property-list input[type="radio"] {
  width: auto;
  accent-color: var(--colour-teal);
}

/* ===== Results Summary ===== */
.results-summary {
  margin-top: 1rem;
}

.results-summary dl {
  display: grid;
  grid-template-columns: auto 1fr;
  gap: 0.25rem 1rem;
  font-size: 0.9rem;
}

.results-summary dt {
  font-weight: 600;
  color: var(--colour-navy);
}

.results-summary dd {
  color: var(--colour-dark);
}

/* ===== Pricing Parameters Card ===== */
.card-intro {
  font-size: 0.875rem;
  color: var(--colour-dark);
  opacity: 0.75;
  margin-bottom: 1rem;
}

.params-grid {
  display: grid;
  grid-template-columns: 1fr auto;
  gap: 0.5rem 1rem;
  align-items: center;
}

.params-grid label {
  font-size: 0.875rem;
  font-weight: 500;
}

.params-grid input {
  width: 7rem;
  text-align: right;
}

.unit {
  font-size: 0.8rem;
  color: var(--colour-dark);
  opacity: 0.7;
  margin-left: 0.25rem;
}

/* ===== Break-even Interpretation Text ===== */
.break-even-text {
  font-size: 0.9rem;
  color: var(--colour-dark);
  margin-top: 1rem;
  padding: 0.75rem 1rem;
  background: var(--colour-light-grey);
  border-left: 3px solid var(--colour-teal);
  border-radius: 0 var(--radius) var(--radius) 0;
}

/* ===== Energy Summary Table ===== */
.energy-summary-table {
  width: 100%;
  border-collapse: collapse;
  font-size: 0.9rem;
  margin-top: 0.5rem;
}

.energy-summary-table th {
  text-align: left;
  font-weight: 600;
  color: var(--colour-navy);
  padding: 0.4rem 0.75rem;
  border-bottom: 2px solid var(--colour-border);
}

.energy-summary-table th:not(:first-child) {
  text-align: right;
}

.energy-summary-table td {
  padding: 0.4rem 0.75rem;
  border-bottom: 1px solid var(--colour-border);
  color: var(--colour-dark);
}

.energy-summary-table td:not(:first-child) {
  text-align: right;
}

.energy-summary-table tfoot .total-row td {
  font-weight: 600;
  border-top: 2px solid var(--colour-border);
  border-bottom: none;
}

.table-scroll-wrap {
  overflow-x: auto;
  -webkit-overflow-scrolling: touch;
}

.field-note {
  font-size: 0.8rem;
  color: var(--colour-dark);
  opacity: 0.75;
  margin-top: 0.5rem;
}

/* ===== Tile divider (within a combined card) ===== */
.tile-divider {
  border: none;
  border-top: 1px solid var(--colour-border);
  margin: 1.5rem 0;
}

/* ===== Preset buttons ===== */
.preset-group {
  display: flex;
  gap: 0.5rem;
  flex-wrap: wrap;
  margin-bottom: 1rem;
}
.preset-btn {
  padding: 0.35rem 0.75rem;
  border: 1.5px solid var(--colour-teal);
  border-radius: var(--radius);
  background: #fff;
  color: var(--colour-teal);
  font-family: var(--font-heading);
  font-size: 0.85rem;
  font-weight: 600;
  cursor: pointer;
  transition: background 0.15s, color 0.15s;
}
.preset-btn.active {
  background: var(--colour-teal);
  color: #fff;
}
.preset-btn:hover:not(.active) { background: #f0f7f7; }

/* ===== Info popout (Avoided AC and future fields) ===== */
.info-popout {
  display: inline-block;
  position: relative;
  margin-left: 0.35rem;
}
.info-icon {
  cursor: pointer;
  list-style: none;
  color: var(--colour-teal);
  font-size: 0.95rem;
  font-weight: 600;
  user-select: none;
}
.info-icon::-webkit-details-marker { display: none; }
.info-popout[open] .info-icon { color: var(--colour-coral); }
.info-content {
  position: absolute;
  top: 1.6rem;
  left: 0;
  z-index: 10;
  width: 22rem;
  max-width: 90vw;
  padding: 0.75rem 0.9rem;
  background: #fff;
  border: 1px solid var(--colour-border);
  border-radius: var(--radius);
  box-shadow: 0 2px 8px rgba(0, 0, 0, 0.08);
  font-size: 0.85rem;
  line-height: 1.5;
  color: var(--colour-dark);
  font-weight: normal;
}

/* ===== What If output areas ===== */
.wi-output {
  margin-top: 0.75rem;
  font-size: 0.9rem;
  color: var(--colour-dark);
}
.wi-output p { margin: 0.2rem 0; }

/* ===== Utility ===== */
.hidden { display: none; }

/* ===== Section Banners ===== */
.section-banner {
  margin: 2rem 0 0.5rem;
}

.section-heading {
  font-size: 1.15rem;
  font-weight: 700;
  color: var(--colour-navy);
  border-bottom: 2px solid var(--colour-teal);
  padding-bottom: 0.35rem;
  margin-bottom: 0;
}

/* ===== Paired-tile grid ===== */
.section-tiles {
  display: grid;
  grid-template-columns: repeat(2, minmax(0, 1fr));
  gap: 1.5rem;
  margin-bottom: 1.5rem;
}

@media (max-width: 768px) {
  .section-tiles {
    grid-template-columns: 1fr;
    gap: 1rem;
  }
}

/* ===== "What drove this answer" tile ===== */
.drove-title {
  font-size: 1rem;
  color: var(--colour-navy);
  margin-bottom: 1rem;
  font-family: Montserrat, sans-serif;
}
.drove-stats { display: flex; flex-direction: column; }
.drove-stat {
  display: flex;
  flex-direction: column;
  padding: 0.85rem 0;
  border-bottom: 1px solid var(--colour-border);
}
.drove-stat:last-child { border-bottom: none; padding-bottom: 0; }
.drove-stat:first-child { padding-top: 0; }
.drove-label {
  font-size: 0.72rem;
  text-transform: uppercase;
  letter-spacing: 0.06em;
  color: var(--colour-navy);
  font-weight: 600;
  margin-bottom: 0.2rem;
}
.drove-value {
  font-size: 1.35rem;
  font-weight: 600;
  color: var(--colour-dark);
  font-family: Montserrat, sans-serif;
  line-height: 1.3;
}
.drove-context {
  font-size: 0.85rem;
  color: var(--colour-dark);
  opacity: 0.7;
  margin-top: 0.15rem;
}

/* ===== Methodology Disclosure ===== */
.methodology-disclosure {
  margin-bottom: 1.5rem;
}

.methodology-summary {
  display: block;
  font-size: 0.95rem;
  font-weight: 600;
  color: var(--colour-teal);
  cursor: pointer;
  padding: 0.75rem 1rem;
  background: var(--colour-light-grey);
  border: 1px solid var(--colour-border);
  border-radius: var(--radius);
  user-select: none;
}

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

.methodology-summary::before {
  content: '▶  ';
  font-size: 0.75em;
}

details[open] .methodology-summary::before {
  content: '▼  ';
}

/* ===== Verdict Card ===== */
.verdict-card {
  border-left: 4px solid var(--colour-teal);
}

.verdict-headline {
  font-size: 1rem;
  line-height: 1.7;
  color: var(--colour-dark);
}

.verdict-headline strong {
  color: var(--colour-navy);
}

.verdict-chart-wrap {
  height: 260px;
  margin: 1.25rem 0;
}

.verdict-quality {
  font-size: 0.82rem;
  color: var(--colour-dark);
  opacity: 0.65;
  margin-top: 0.75rem;
  border-top: 1px solid var(--colour-border);
  padding-top: 0.75rem;
}


/* ===== Underheat diagnostic ===== */
.underheat-light {
  display: inline-block;
  width: 0.75rem;
  height: 0.75rem;
  border-radius: 50%;
  margin-left: 0.5rem;
  vertical-align: middle;
}
.underheat-light.green { background: #2E7D32; }
.underheat-light.amber { background: #F57F17; }
.underheat-narrative {
  font-size: 0.9rem;
  color: var(--colour-dark);
  margin-top: 0.75rem;
  padding: 0.75rem 1rem;
  background: var(--colour-light-grey);
  border-left: 3px solid var(--colour-teal);
  border-radius: 0 var(--radius) var(--radius) 0;
}

/* ===== Responsive ===== */
@media (max-width: 768px) {
  .container { padding: 1rem 0.75rem; }
  header h1 { font-size: 1.3rem; }
  .form-row { grid-template-columns: 1fr; }
}

@media (max-width: 375px) {
  .container { padding: 0.75rem 0.5rem; }
  header h1 { font-size: 1.15rem; }
  .card { padding: 1rem; }
  .btn { padding: 0.5rem 1rem; font-size: 0.9rem; }
}

/* ===== Summary DL (methodology cards) ===== */
.summary-dl {
  display: grid;
  grid-template-columns: auto 1fr;
  gap: 0.25rem 1rem;
  font-size: 0.9rem;
  margin-top: 0.5rem;
}
.summary-dl dt { font-weight: 600; color: var(--colour-navy); }
.summary-dl dd { color: var(--colour-dark); }

/* ===== Verdict status line ===== */
.verdict-status {
  margin: 0.75rem 0 0.25rem;
  padding: 0.65rem 0.9rem;
  background: #FFF8E1;
  color: #8B5A00;
  border-left: 3px solid #F57F17;
  border-radius: 0 var(--radius) var(--radius) 0;
  font-size: 0.9rem;
  line-height: 1.5;
}
.verdict-status .fix-link {
  color: var(--colour-teal);
  font-weight: 600;
  text-decoration: underline;
  cursor: pointer;
  background: none;
  border: none;
  padding: 0;
  font-size: inherit;
  font-family: inherit;
  margin-left: 0.25rem;
}
.verdict-status .fix-link:hover { color: #2A6566; }
.highlight-flash {
  outline: 2px solid var(--colour-coral);
  outline-offset: 2px;
  transition: outline 0.3s ease;
}

/* ===== Status notices collapse ===== */
.status-details { margin-top: 0.75rem; }
.status-summary {
  cursor: pointer;
  font-size: 0.9rem;
  font-weight: 600;
  color: var(--colour-navy);
  list-style: none;
  padding: 0.4rem 0;
}
.status-summary::-webkit-details-marker { display: none; }
.status-summary::before { content: '▶ '; font-size: 0.75rem; }
details[open] .status-summary::before { content: '▼ '; }