:root {
  --blue-900:  #1e3a5f;
  --blue-700:  #1d4ed8;
  --blue-500:  #3b82f6;
  --blue-50:   #eff6ff;
  --green-700: #15803d;
  --green-500: #10b981;
  --green-50:  #f0fdf4;
  --red-400:   #f87171;
  --red-500:   #ef4444;
  --amber-500: #f59e0b;
  --amber-400: #fbbf24;
  --gray-50:   #f8fafc;
  --gray-100:  #f1f5f9;
  --gray-200:  #e2e8f0;
  --gray-400:  #94a3b8;
  --gray-500:  #64748b;
  --gray-800:  #1e293b;
  --white:     #ffffff;
  --radius-sm: 6px;
  --radius-md: 10px;
  --radius-lg: 14px;
  --shadow:    0 1px 3px rgba(0,0,0,.08), 0 1px 2px rgba(0,0,0,.04);
}

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

body {
  font-family: -apple-system, BlinkMacSystemFont, 'Segoe UI', system-ui, sans-serif;
  background: var(--gray-50);
  color: var(--gray-800);
  line-height: 1.5;
  min-height: 100vh;
  overflow-x: hidden;
}

/* Eliminate 300ms tap delay on all interactive elements */
button, a, input, select, [role="button"] { touch-action: manipulation; }

/* ── HEADER ─────────────────────────────── */
header {
  background: linear-gradient(135deg, var(--blue-900) 0%, #2d5a8e 100%);
  color: var(--white);
  padding: 1.125rem 2rem;
  display: flex;
  align-items: center;
  justify-content: space-between;
  gap: 1rem;
  box-shadow: 0 2px 8px rgba(0,0,0,.15);
}

.header-title h1 { font-size: 1.2rem; font-weight: 700; letter-spacing: -0.03em; }
.header-title p  { font-size: 0.78rem; opacity: 0.55; margin-top: 1px; }

.header-controls { display: flex; align-items: center; gap: 0.625rem; flex-shrink: 0; flex-wrap: wrap; }

.header-btn {
  background: rgba(255,255,255,.13);
  border: 1px solid rgba(255,255,255,.22);
  color: rgba(255,255,255,.9);
  padding: 0.45rem 0.875rem;
  border-radius: var(--radius-sm);
  font-size: 0.8rem;
  font-weight: 500;
  cursor: pointer;
  transition: background .15s;
  white-space: nowrap;
  min-height: 2.25rem;
}
.header-btn:hover { background: rgba(255,255,255,.24); }

.currency-picker { display: flex; align-items: center; gap: 0.4rem; font-size: 0.8rem; }
.currency-picker label { opacity: 0.65; font-weight: 500; }
.currency-picker select {
  background: rgba(255,255,255,.12);
  border: 1px solid rgba(255,255,255,.22);
  color: var(--white);
  padding: 0.3rem 0.6rem;
  border-radius: var(--radius-sm);
  font-size: 0.8rem;
  cursor: pointer;
}
.currency-picker select:hover { border-color: rgba(255,255,255,.45); }
.currency-picker select option { background: var(--blue-900); }

/* ── LAYOUT ─────────────────────────────── */
main {
  max-width: 1120px;
  margin: 0 auto;
  padding: 1.75rem 1.5rem 3rem;
  display: grid;
  gap: 1.25rem;
}

.card {
  background: var(--white);
  border-radius: var(--radius-lg);
  box-shadow: var(--shadow);
  padding: 1.375rem;
}

/* Card header with h2 + controls on same row */
.card-header-row {
  display: flex;
  align-items: center;
  justify-content: space-between;
  flex-wrap: wrap;
  gap: 0.625rem;
  margin-bottom: 1.125rem;
}
.card-header-row h2 { margin-bottom: 0; }

.card h2 { font-size: 0.9rem; font-weight: 700; color: var(--blue-900); margin-bottom: 1.125rem; letter-spacing: -0.01em; }

/* ── TOGGLE GROUPS ──────────────────────── */
.toggle-group {
  display: flex;
  background: var(--gray-100);
  border-radius: var(--radius-sm);
  padding: 3px;
  width: fit-content;
}

.toggle-btn {
  padding: 0.35rem 0.8rem;
  border: none;
  background: transparent;
  border-radius: calc(var(--radius-sm) - 1px);
  font-size: 0.8rem;
  font-weight: 500;
  cursor: pointer;
  color: var(--gray-500);
  transition: all .15s;
  white-space: nowrap;
  min-height: 2.25rem;
}

.toggle-btn.active { background: var(--white); color: var(--gray-800); box-shadow: 0 1px 3px rgba(0,0,0,.1); }

/* ── INPUT GRID ─────────────────────────── */
.input-grid {
  display: grid;
  grid-template-columns: repeat(auto-fill, minmax(185px, 1fr));
  gap: 0.875rem 1.125rem;
}

.field { display: flex; flex-direction: column; gap: 0.3rem; }

.field label {
  font-size: 0.71rem; font-weight: 700;
  color: var(--gray-500); letter-spacing: 0.05em; text-transform: uppercase;
}

.field input, .field select {
  width: 100%;
  padding: 0.5rem 0.8rem;
  border: 1.5px solid var(--gray-200);
  border-radius: var(--radius-md);
  font-size: 0.925rem;
  color: var(--gray-800);
  background: var(--white);
  transition: border-color .15s, box-shadow .15s;
  outline: none;
  /* Ensure 44px tap targets on all screen sizes */
  min-height: 2.75rem;
}

.field input {
  appearance: textfield;
  -moz-appearance: textfield;
}

.field input::-webkit-outer-spin-button,
.field input::-webkit-inner-spin-button { -webkit-appearance: none; }

.field input:focus, .field select:focus {
  border-color: var(--blue-500);
  box-shadow: 0 0 0 3px rgba(59,130,246,.13);
}

.field select {
  appearance: none;
  cursor: pointer;
  padding-right: 2.25rem;
  background-image: url("data:image/svg+xml,%3Csvg xmlns='http://www.w3.org/2000/svg' width='12' height='8' fill='none'%3E%3Cpath d='M1 1l5 5 5-5' stroke='%2394a3b8' stroke-width='1.5' stroke-linecap='round' stroke-linejoin='round'/%3E%3C/svg%3E");
  background-repeat: no-repeat;
  background-position: right 0.8rem center;
}

.field .hint { font-size: 0.72rem; color: var(--gray-400); min-height: 1.1em; }

.derived-value {
  display: flex; align-items: center;
  padding: 0.5rem 0.8rem;
  background: var(--blue-50); border: 1.5px solid #bfdbfe;
  border-radius: var(--radius-md);
  font-size: 0.925rem; font-weight: 600; color: var(--blue-700);
  min-height: 2.75rem;
}

/* ── SECTION SEPARATOR ──────────────────── */
.section-sep { border: none; border-top: 1px solid var(--gray-100); margin: 1.25rem 0 1rem; }

/* ── RATE PERIODS ───────────────────────── */
.rp-header {
  display: flex; align-items: center; justify-content: space-between; margin-bottom: 0.75rem;
}
.rp-header-label { font-size: 0.71rem; font-weight: 700; color: var(--gray-500); letter-spacing: 0.05em; text-transform: uppercase; }

.btn-secondary {
  padding: 0.35rem 0.75rem;
  background: var(--blue-50); color: var(--blue-700); border: 1px solid #bfdbfe;
  border-radius: var(--radius-sm); font-size: 0.8rem; font-weight: 600;
  cursor: pointer; transition: background .15s; white-space: nowrap;
  min-height: 2.25rem;
}
.btn-secondary:hover { background: #dbeafe; }

.rp-list { display: flex; flex-direction: column; gap: 0.4rem; }

.rp-row {
  display: flex; align-items: center; gap: 0.625rem;
  padding: 0.5rem 0.75rem;
  background: var(--gray-50); border: 1px solid var(--gray-200); border-radius: var(--radius-md);
}

.rp-label { font-size: 0.775rem; font-weight: 600; color: var(--gray-400); min-width: 4.25rem; flex-shrink: 0; }

.rp-field { display: flex; align-items: center; gap: 0.3rem; flex: 1; }

.rp-field input {
  width: 100%; max-width: 5.75rem;
  padding: 0.325rem 0.575rem;
  border: 1.5px solid var(--gray-200); border-radius: var(--radius-sm);
  font-size: 0.85rem; color: var(--gray-800); background: var(--white);
  outline: none; transition: border-color .15s, box-shadow .15s;
  appearance: textfield; -moz-appearance: textfield;
  min-height: 2.25rem;
}
.rp-field input::-webkit-outer-spin-button,
.rp-field input::-webkit-inner-spin-button { -webkit-appearance: none; }
.rp-field input:focus { border-color: var(--blue-500); box-shadow: 0 0 0 2px rgba(59,130,246,.13); }
.rp-field input:disabled { background: var(--gray-100); color: var(--gray-400); cursor: not-allowed; }

.rp-unit { font-size: 0.775rem; color: var(--gray-400); flex-shrink: 0; }

.rp-remove {
  width: 2.25rem; height: 2.25rem;
  display: flex; align-items: center; justify-content: center;
  background: transparent; border: 1px solid var(--gray-200); border-radius: var(--radius-sm);
  color: var(--gray-400); font-size: 1rem; cursor: pointer; flex-shrink: 0; transition: all .15s; line-height: 1;
}
.rp-remove:hover:not(:disabled) { background: #fef2f2; border-color: #fecaca; color: var(--red-500); }
.rp-remove:disabled { cursor: not-allowed; opacity: 0.3; }

.rp-footer { margin-top: 0.625rem; }
.rp-total { font-size: 0.775rem; font-weight: 500; }
.rp-total.ok   { color: var(--green-500); }
.rp-total.warn { color: var(--amber-500); }

/* ── ONE-OFF LUMP SUMS ──────────────────── */
.lump-row {
  display: flex; align-items: center; gap: 0.5rem;
  padding: 0.4rem 0;
  border-bottom: 1px solid var(--gray-100);
}
.lump-row:last-child { border-bottom: none; }
.lump-amount-wrap { flex: 2; }
.lump-month-wrap  { flex: 1; }
.lump-amount-wrap input, .lump-month-wrap input {
  width: 100%;
  padding: 0.325rem 0.575rem;
  border: 1.5px solid var(--gray-200); border-radius: var(--radius-sm);
  font-size: 0.85rem; color: var(--gray-800); background: var(--white);
  outline: none; transition: border-color .15s, box-shadow .15s;
  appearance: textfield; -moz-appearance: textfield;
  min-height: 2.25rem;
}
.lump-amount-wrap input::-webkit-outer-spin-button,
.lump-amount-wrap input::-webkit-inner-spin-button,
.lump-month-wrap input::-webkit-outer-spin-button,
.lump-month-wrap input::-webkit-inner-spin-button { -webkit-appearance: none; }
.lump-amount-wrap input:focus, .lump-month-wrap input:focus {
  border-color: var(--blue-500); box-shadow: 0 0 0 2px rgba(59,130,246,.13);
}
.lump-sep { font-size: 0.775rem; color: var(--gray-400); flex-shrink: 0; white-space: nowrap; }

/* ── ERROR MSG ──────────────────────────── */
.error-msg {
  margin-top: 0.875rem; padding: 0.5rem 0.75rem;
  background: #fef2f2; border: 1px solid #fecaca; border-radius: var(--radius-sm);
  color: var(--red-500); font-size: 0.8rem; display: none;
}

/* ── SUMMARY CARDS ──────────────────────── */
.summary-grid {
  display: grid;
  grid-template-columns: repeat(auto-fill, minmax(195px, 1fr));
  gap: 0.875rem;
}

.summary-card {
  padding: 1rem 1.125rem; border-radius: var(--radius-md);
  background: var(--gray-50); border: 1px solid var(--gray-200);
  display: flex; flex-direction: column; gap: 0.2rem;
}
.summary-card .s-label { font-size: 0.68rem; font-weight: 700; text-transform: uppercase; letter-spacing: 0.07em; color: var(--gray-400); }
.summary-card .s-value { font-size: 1.55rem; font-weight: 800; letter-spacing: -0.04em; color: var(--blue-900); line-height: 1.15; word-break: break-word; }
.summary-card .s-sub   { font-size: 0.72rem; color: var(--gray-400); }

.summary-card.primary { background: linear-gradient(135deg, var(--blue-900), #2d5a8e); border-color: transparent; }
.summary-card.primary .s-label { color: rgba(255,255,255,.55); }
.summary-card.primary .s-value { color: var(--white); }
.summary-card.primary .s-sub   { color: rgba(255,255,255,.45); }

/* ── SAVINGS CARDS ──────────────────────── */
.sav-card {
  padding: 1rem 1.125rem; border-radius: var(--radius-md);
  background: var(--green-50); border: 1px solid #bbf7d0;
  display: flex; flex-direction: column; gap: 0.2rem;
}
.sav-card .sav-label { font-size: 0.68rem; font-weight: 700; text-transform: uppercase; letter-spacing: 0.07em; color: var(--green-700); }
.sav-card .sav-value { font-size: 1.55rem; font-weight: 800; letter-spacing: -0.04em; color: var(--green-500); line-height: 1.15; word-break: break-word; }
.sav-card .sav-sub   { font-size: 0.72rem; color: #4ade80; }

/* ── CHARTS ─────────────────────────────── */
.charts-grid {
  display: grid;
  grid-template-columns: 1fr 1fr;
  gap: 1.25rem 1rem;
}

.chart-col-full { grid-column: 1 / -1; }

.chart-title {
  font-size: 0.68rem;
  font-weight: 700;
  text-transform: uppercase;
  letter-spacing: 0.07em;
  color: var(--gray-400);
  margin-bottom: 0.5rem;
}

.chart-wrap { position: relative; height: 190px; }
.chart-col-full .chart-wrap { height: 210px; }

/* ── AMORTIZATION TABLE ─────────────────── */
.table-actions { display: flex; gap: 0.4rem; align-items: center; flex-shrink: 0; }

.collapsible-body {
  overflow: hidden;
  max-height: 560px;
  transition: max-height 0.28s ease, opacity 0.28s ease;
  opacity: 1;
}
.collapsible-body.is-collapsed {
  max-height: 0;
  opacity: 0;
}

.table-wrapper {
  overflow: auto;
  max-height: 440px;
  border-radius: var(--radius-md);
  border: 1px solid var(--gray-200);
  /* Enable momentum scrolling on iOS */
  -webkit-overflow-scrolling: touch;
}

table {
  width: 100%;
  border-collapse: collapse;
  font-size: 0.85rem;
  font-variant-numeric: tabular-nums;
  /* Prevent columns from squishing on small screens; enables horizontal scroll */
  min-width: 480px;
}

thead { position: sticky; top: 0; z-index: 1; }

thead th {
  background: var(--blue-900); color: rgba(255,255,255,.82);
  padding: 0.675rem 0.875rem; text-align: right;
  font-weight: 600; font-size: 0.71rem; letter-spacing: 0.05em; text-transform: uppercase; white-space: nowrap;
}
thead th:first-child { text-align: left; }

tbody tr { border-bottom: 1px solid var(--gray-100); transition: background .1s; }
tbody tr:last-child { border-bottom: none; }
tbody tr:hover { background: var(--blue-50); }

tbody tr.year-row { background: var(--gray-100); }
tbody tr.year-row:hover { background: #dbeafe; }
tbody tr.year-row td:first-child { font-weight: 600; color: var(--blue-900); }

tbody td {
  padding: 0.45rem 0.875rem;
  text-align: right;
  color: var(--gray-800);
  white-space: nowrap;
}
tbody td:first-child { text-align: left; color: var(--gray-500); font-size: 0.785rem; }

.td-interest  { color: var(--red-400)   !important; }
.td-principal { color: var(--green-500) !important; }
.td-balance   { color: var(--gray-500)  !important; font-size: 0.785rem; }
.td-extra     { color: var(--amber-400) !important; font-weight: 500; }

/* Hide extra column when no extras are active */
table:not(.has-extras) .th-extra,
table:not(.has-extras) .td-extra { display: none; }

tbody tr.rate-divider { pointer-events: none; }
tbody tr.rate-divider td {
  background: #1e3a5f; color: rgba(255,255,255,.72);
  text-align: center; font-size: 0.71rem; font-weight: 600;
  padding: 0.3rem 0.875rem; letter-spacing: 0.05em; text-transform: uppercase;
}

/* ── RESPONSIVE ─────────────────────────── */

/* — ≤680px: tablet / large phones — */
@media (max-width: 680px) {
  header {
    flex-direction: column;
    align-items: flex-start;
    padding: 1rem 1.125rem;
    gap: 0.625rem;
  }

  .header-controls {
    flex-wrap: wrap;
    width: 100%;
    gap: 0.5rem;
  }

  /* Let the currency picker fill remaining space in the header row */
  .currency-picker { flex: 1; min-width: 0; }
  .currency-picker select { flex: 1; min-width: 0; width: 100%; }

  main { padding: 0.875rem 0.875rem 2rem; gap: 1rem; }
  .card { padding: 1rem; }

  .card-header-row { flex-direction: column; align-items: flex-start; }

  /* Bigger tap targets for buttons on touch screens */
  .toggle-btn   { padding: 0.5rem 0.75rem; min-height: 2.75rem; }
  .btn-secondary { padding: 0.5rem 0.875rem; min-height: 2.75rem; }
  .rp-remove    { width: 2.75rem; height: 2.75rem; }

  .summary-grid { grid-template-columns: 1fr 1fr; }
  .summary-card .s-value { font-size: 1.2rem; }
  .sav-card .sav-value   { font-size: 1.2rem; }

  .charts-grid { grid-template-columns: 1fr; }
  .chart-col-full { grid-column: 1; }
  .chart-wrap, .chart-col-full .chart-wrap { height: 175px; }

  thead th, tbody td { padding: 0.4rem 0.5rem; font-size: 0.775rem; }

  /* Rate period rows: label on own line, inputs fill space */
  .rp-row { flex-wrap: wrap; }
  .rp-label { min-width: 100%; margin-bottom: 0.1rem; }
  /* Remove max-width cap so inputs fill available flex space */
  .rp-field input { max-width: none; min-height: 2.75rem; }

  /* Lump sum inputs on mobile */
  .lump-amount-wrap input, .lump-month-wrap input { min-height: 2.75rem; }

  .table-actions { flex-wrap: wrap; }
}

/* — ≤480px: most phones — */
@media (max-width: 480px) {
  main { padding: 0.75rem 0.75rem 2rem; }
  .card { padding: 0.875rem; }
}

/* — ≤420px: narrow phones (360–420px) — */
@media (max-width: 420px) {
  .input-grid { grid-template-columns: 1fr; }
  .summary-grid { grid-template-columns: 1fr; }
}

/* ── FOOTER ─────────────────────────────── */
footer {
  border-top: 1px solid var(--gray-200);
  padding: 1.25rem 1.5rem 2rem;
  margin-top: 0.25rem;
}

.footer-inner {
  max-width: 1120px;
  margin: 0 auto;
  display: flex;
  align-items: center;
  justify-content: space-between;
  flex-wrap: wrap;
  gap: 0.375rem 1rem;
}

.footer-links {
  display: flex;
  align-items: center;
  flex-wrap: wrap;
  gap: 0.25rem 0.5rem;
  font-size: 0.78rem;
  color: var(--gray-500);
}

.footer-links a {
  color: var(--gray-500);
  text-decoration: none;
  transition: color .15s;
}
.footer-links a:hover,
.footer-links a:focus-visible { color: var(--gray-800); text-decoration: underline; }

.footer-sep { color: var(--gray-400); user-select: none; }

.footer-disclaimer {
  font-size: 0.72rem;
  color: var(--gray-400);
  margin: 0;
}

@media (max-width: 680px) {
  footer { padding: 1rem 0.875rem 2rem; }
  .footer-inner { flex-direction: column; align-items: flex-start; gap: 0.375rem; }
}

@media (max-width: 480px) {
  footer { padding: 1rem 0.75rem 2rem; }
}