*, *::before, *::after { box-sizing: border-box; margin: 0; padding: 0; }

:root {
  --kv-bg:      #0f172a;
  --kv-card:    #1e293b;
  --kv-card-2:  #263248;
  --kv-text:    #f1f5f9;
  --kv-muted:   #94a3b8;
  --kv-border:  #334155;
  --kv-accent:  #38bdf8;
  --kv-pass:    #22c55e;
  --kv-fail:    #ef4444;
  --kv-warn:    #f59e0b;
}

body {
  font-family: system-ui, -apple-system, sans-serif;
  background: var(--kv-bg);
  color: var(--kv-text);
  min-height: 100vh;
  font-size: 15px;
  line-height: 1.5;
}

/* ── Header ── */

.app-header {
  padding: 20px 16px 14px;
  border-bottom: 1px solid var(--kv-border);
  position: relative;
  text-align: center;
}

.home-logo {
  position: absolute;
  top: 18px;
  left: 16px;
}

.home-logo img { width: 32px; height: 32px; opacity: 0.9; display: block; }
.home-logo:hover img { opacity: 1; }

.app-header h1 { font-size: 1.5rem; font-weight: 700; letter-spacing: -0.02em; }
.app-header > p { color: var(--kv-muted); font-size: 0.88rem; margin-top: 4px; }

.header-concepts {
  display: flex;
  flex-wrap: wrap;
  justify-content: center;
  gap: 8px;
  margin-top: 12px;
}

.concept-pill {
  background: rgba(56, 189, 248, 0.08);
  border: 1px solid rgba(56, 189, 248, 0.2);
  border-radius: 20px;
  padding: 4px 14px;
  font-size: 0.8rem;
  color: var(--kv-muted);
}

/* ── Layout ── */

main {
  max-width: 1120px;
  margin: 0 auto;
  padding: 24px 24px 48px;
}

.layout {
  display: grid;
  grid-template-columns: 360px 1fr;
  gap: 20px;
  align-items: start;
  margin-top: 20px;
}

@media (max-width: 800px) {
  .layout { grid-template-columns: 1fr; }
}

/* ── Input panel ── */

.input-panel {
  display: flex;
  flex-direction: column;
  gap: 12px;
}

.input-group {
  background: var(--kv-card);
  border: 1px solid var(--kv-border);
  border-radius: 12px;
  padding: 20px;
  display: flex;
  flex-direction: column;
  gap: 16px;
}

.group-title {
  font-size: 0.78rem;
  font-weight: 600;
  text-transform: uppercase;
  letter-spacing: 0.06em;
  color: var(--kv-muted);
  margin-bottom: 2px;
}

.field {
  display: flex;
  flex-direction: column;
  gap: 4px;
}

.field label {
  font-size: 0.875rem;
  font-weight: 500;
  color: var(--kv-text);
  display: flex;
  align-items: center;
  gap: 6px;
}

.input-wrap {
  display: flex;
  align-items: center;
  background: var(--kv-bg);
  border: 1px solid var(--kv-border);
  border-radius: 8px;
  overflow: hidden;
  transition: border-color 0.15s;
}

.input-wrap:focus-within {
  border-color: var(--kv-accent);
}

.currency-prefix,
.pct-suffix,
.unit-suffix {
  padding: 0 10px;
  color: var(--kv-muted);
  font-size: 0.875rem;
  flex-shrink: 0;
  user-select: none;
}

.money-input,
.num-input {
  background: transparent;
  border: none;
  color: var(--kv-text);
  font-size: 0.95rem;
  padding: 9px 10px;
  width: 100%;
  outline: none;
  font-family: inherit;
}

.pct-input {
  text-align: right;
}

.num-input::-webkit-inner-spin-button,
.num-input::-webkit-outer-spin-button {
  opacity: 0.4;
}

.freq-select {
  background: var(--kv-bg);
  border: 1px solid var(--kv-border);
  border-radius: 8px;
  color: var(--kv-text);
  padding: 9px 12px;
  width: 100%;
  font-size: 0.95rem;
  outline: none;
  font-family: inherit;
  appearance: none;
  cursor: pointer;
  transition: border-color 0.15s;
}

.freq-select:focus {
  border-color: var(--kv-accent);
}

/* ── Loan type toggle ── */

.toggle-group {
  display: flex;
  border-radius: 8px;
  overflow: hidden;
  border: 1px solid var(--kv-border);
}

.toggle-btn {
  flex: 1;
  background: var(--kv-bg);
  border: none;
  color: var(--kv-muted);
  padding: 9px 8px;
  cursor: pointer;
  font-size: 0.875rem;
  font-family: inherit;
  transition: background 0.15s, color 0.15s;
}

.toggle-btn.active {
  background: var(--kv-accent);
  color: #0f172a;
  font-weight: 600;
}

/* ── IO period field — hidden by default ── */

.io-period-field {
  display: none;
}

.io-period-field.visible {
  display: flex;
}

/* ── Derived text ── */

.derived {
  font-size: 0.8rem;
  color: var(--kv-accent);
  min-height: 1.1em;
}

.derived-savings {
  font-size: 0.8rem;
  color: var(--kv-pass);
  min-height: 1.1em;
}

/* ── Tooltip ── */

.tip {
  display: inline-flex;
  align-items: center;
  justify-content: center;
  width: 16px;
  height: 16px;
  border-radius: 50%;
  background: var(--kv-border);
  color: var(--kv-muted);
  font-size: 0.7rem;
  cursor: default;
  position: relative;
  flex-shrink: 0;
}

.tip:hover::after {
  content: attr(data-tip);
  position: absolute;
  left: 22px;
  top: -4px;
  background: var(--kv-card-2);
  border: 1px solid var(--kv-border);
  border-radius: 8px;
  padding: 8px 12px;
  font-size: 0.78rem;
  color: var(--kv-text);
  white-space: pre-wrap;
  width: 220px;
  z-index: 20;
  line-height: 1.5;
  font-weight: 400;
}

/* ── Results panel ── */

.results-panel {
  min-width: 0;
  display: flex;
  flex-direction: column;
  gap: 16px;
}

/* ── Cards ── */

.cards {
  display: grid;
  grid-template-columns: repeat(2, 1fr);
  gap: 12px;
}

@media (max-width: 560px) {
  .cards { grid-template-columns: 1fr; }
}

.card {
  background: var(--kv-card);
  border: 1px solid var(--kv-border);
  border-radius: 12px;
  padding: 20px;
  min-width: 0;
}

.summary-card {
  display: flex;
  flex-direction: column;
  gap: 4px;
}

.card-label {
  font-size: 0.78rem;
  font-weight: 600;
  text-transform: uppercase;
  letter-spacing: 0.05em;
  color: var(--kv-muted);
}

.card-value {
  font-size: 1.7rem;
  font-weight: 700;
  letter-spacing: -0.02em;
  color: var(--kv-text);
  line-height: 1.1;
}

.card-sub {
  font-size: 0.8rem;
  color: var(--kv-muted);
}

.card-title {
  font-size: 0.95rem;
  font-weight: 600;
  color: var(--kv-text);
  margin-bottom: 14px;
}

/* ── Savings banner ── */

.savings-banner {
  background: rgba(34, 197, 94, 0.07);
  border-color: rgba(34, 197, 94, 0.3);
  display: flex;
  gap: 24px;
  flex-wrap: wrap;
  align-items: center;
}

.save-item {
  display: flex;
  flex-direction: column;
  gap: 2px;
}

.save-label {
  font-size: 0.78rem;
  font-weight: 600;
  text-transform: uppercase;
  letter-spacing: 0.05em;
  color: var(--kv-muted);
}

.save-value {
  font-size: 1.5rem;
  font-weight: 700;
  color: var(--kv-pass);
  letter-spacing: -0.02em;
  line-height: 1.1;
}

/* ── Frequency comparison table ── */

.freq-table {
  width: 100%;
  border-collapse: collapse;
  font-size: 0.875rem;
}

.freq-table th {
  text-align: right;
  color: var(--kv-muted);
  font-weight: 600;
  font-size: 0.78rem;
  text-transform: uppercase;
  letter-spacing: 0.04em;
  padding: 0 8px 10px;
  border-bottom: 1px solid var(--kv-border);
}

.freq-table th:first-child {
  text-align: left;
}

.freq-table td {
  text-align: right;
  padding: 10px 8px;
  border-bottom: 1px solid rgba(51, 65, 85, 0.5);
  color: var(--kv-muted);
  font-variant-numeric: tabular-nums;
}

.freq-table td:first-child {
  text-align: left;
}

.freq-table tr:last-child td {
  border-bottom: none;
}

.freq-table .freq-active td {
  color: var(--kv-text);
  font-weight: 500;
}

.freq-table .freq-active td:first-child {
  color: var(--kv-accent);
}

/* ── Chart ── */

.chart-card canvas {
  width: 100% !important;
  height: 260px !important;
  display: block;
}

/* ── Collapsible schedule ── */

details.card > summary {
  cursor: pointer;
  list-style: none;
  display: flex;
  align-items: center;
  justify-content: space-between;
}

details.card > summary::after {
  content: '▶';
  font-size: 0.7rem;
  color: var(--kv-muted);
  transition: transform 0.2s;
}

details.card[open] > summary::after {
  transform: rotate(90deg);
}

details.card > summary .card-title {
  margin-bottom: 0;
}

.table-wrap {
  margin-top: 16px;
  overflow-x: auto;
  min-width: 0;
}

/* ── Amortisation schedule table ── */

.schedule-table {
  width: 100%;
  border-collapse: collapse;
  font-size: 0.82rem;
  min-width: 480px;
}

.schedule-table th {
  text-align: right;
  color: var(--kv-muted);
  font-weight: 600;
  font-size: 0.75rem;
  text-transform: uppercase;
  letter-spacing: 0.04em;
  padding: 0 10px 8px;
  border-bottom: 1px solid var(--kv-border);
}

.schedule-table th:first-child {
  text-align: left;
}

.schedule-table td {
  text-align: right;
  padding: 7px 10px;
  border-bottom: 1px solid rgba(51, 65, 85, 0.4);
  color: var(--kv-muted);
  font-variant-numeric: tabular-nums;
}

.schedule-table td:first-child {
  text-align: left;
  color: var(--kv-text);
}

.schedule-table .gap-row td {
  text-align: center;
  color: var(--kv-border);
  padding: 4px;
  font-size: 0.75rem;
  border-bottom: none;
}

.schedule-note {
  font-size: 0.8rem;
  color: var(--kv-muted);
  margin-top: 10px;
  text-align: center;
}

/* ── Footer ── */

footer {
  max-width: 1120px;
  margin: 0 auto;
  padding: 24px;
  font-size: 0.8rem;
  color: #475569;
  display: flex;
  flex-direction: column;
  gap: 4px;
}

footer a {
  color: var(--kv-muted);
  text-decoration: none;
}

footer a:hover {
  color: var(--kv-accent);
}

/* ── Utilities ── */

.hidden { display: none !important; }

/* ── Print ── */

@media print {
  .app-header .home-logo,
  .input-panel,
  footer { display: none; }

  body { background: white; color: black; }
  .card { border: 1px solid #ccc; break-inside: avoid; }
  details.card { open: true; }
  details.card > summary::after { display: none; }
  .table-wrap { overflow: visible; }
  .results-panel { display: block; }
}