:root {
  --gsm-blue: #0a3d91;
  --gsm-blue-dark: #062a66;
  --gsm-blue-light: #2563c2;
  --gsm-blue-pale: #e8f0fb;
  --gsm-accent: #3a8dde;
  --gsm-success: #28a745;
  --gsm-warn: #ffc107;
  --gsm-danger: #dc3545;
  --gsm-gold: #d4a93b;
  --gsm-text: #1a1f36;
  --gsm-muted: #6b7280;
  --gsm-border: #d8e2f1;
  --bg: #f4f7fc;
  --surface: #ffffff;
  --surface-2: #fafcff;
  --row-hover: #e8f0fb;
  --grid-line: #f0f4fa;
  --shadow: 0 4px 16px rgba(10, 61, 145, 0.08);
  --shadow-lg: 0 12px 40px rgba(10, 61, 145, 0.18);
  --radius: 12px;
  --radius-lg: 18px;
}

[data-theme="dark"] {
  --gsm-blue: #4d8df0;
  --gsm-blue-dark: #6ea3f5;
  --gsm-blue-light: #5e9bf3;
  --gsm-blue-pale: #1c2a44;
  --gsm-accent: #6ea3f5;
  --gsm-gold: #e7c25f;
  --gsm-text: #e6ecf6;
  --gsm-muted: #9aa6bd;
  --gsm-border: #2a3550;
  --bg: #0e1525;
  --surface: #1a2236;
  --surface-2: #141b2c;
  --row-hover: #1f2a44;
  --grid-line: #232c44;
  --shadow: 0 4px 16px rgba(0, 0, 0, 0.4);
  --shadow-lg: 0 12px 40px rgba(0, 0, 0, 0.55);
}

* { box-sizing: border-box; }

html, body { margin: 0; padding: 0; }

body {
  font-family: -apple-system, BlinkMacSystemFont, "Segoe UI", Roboto, Helvetica, Arial, sans-serif;
  background: var(--bg);
  color: var(--gsm-text);
  min-height: 100vh;
}

a { color: var(--gsm-blue); }
button { font-family: inherit; cursor: pointer; border: none; background: none; color: inherit; }
input, select { font-family: inherit; }

.muted { color: var(--gsm-muted); }

/* === Top bar ============================================================ */

.topbar {
  background: var(--surface);
  border-bottom: 1px solid var(--gsm-border);
  padding: 14px 32px;
  display: flex;
  align-items: center;
  justify-content: space-between;
  gap: 16px;
  position: sticky;
  top: 0;
  z-index: 50;
}
.brand { display: flex; align-items: center; gap: 12px; }
.brand-dot {
  width: 42px; height: 42px;
  border-radius: 10px;
  background: linear-gradient(135deg, var(--gsm-blue), var(--gsm-blue-light));
  color: #fff;
  display: flex; align-items: center; justify-content: center;
  font-weight: 800; font-size: 18px;
  box-shadow: var(--shadow);
  letter-spacing: -0.5px;
}
.brand-title { font-weight: 700; font-size: 16px; color: var(--gsm-blue); line-height: 1.2; }
.brand-sub   { font-size: 12px; color: var(--gsm-muted); letter-spacing: 0.04em; text-transform: uppercase; }

.header-right { display: flex; align-items: center; gap: 12px; }

.rate-badge {
  display: flex; flex-direction: column; align-items: flex-end;
  background: var(--gsm-blue-pale);
  border: 1px solid var(--gsm-border);
  padding: 8px 16px;
  border-radius: var(--radius);
  line-height: 1.1;
  min-width: 180px;
}
.rate-label { font-size: 11px; color: var(--gsm-muted); text-transform: uppercase; letter-spacing: 0.05em; }
.rate-value { font-size: 22px; font-weight: 800; color: var(--gsm-blue); }
.rate-asof  { font-size: 10px; color: var(--gsm-muted); margin-top: 2px; }

.theme-toggle {
  width: 38px; height: 38px;
  border-radius: 50%;
  background: var(--surface-2);
  border: 1px solid var(--gsm-border);
  font-size: 18px;
  transition: transform .15s;
}
.theme-toggle:hover { transform: scale(1.05); }

.share-btn {
  display: inline-flex;
  align-items: center;
  gap: 6px;
  padding: 8px 14px;
  background: var(--surface-2);
  border: 1px solid var(--gsm-border);
  border-radius: var(--radius);
  font-size: 13px;
  font-weight: 600;
  color: var(--gsm-blue);
  transition: background .15s, color .15s, border-color .15s;
}
.share-btn:hover { background: var(--gsm-blue); color: #fff; border-color: var(--gsm-blue); }
.share-btn .share-icon { font-size: 14px; line-height: 1; transform: rotate(-15deg); }

.copy-row {
  display: flex;
  gap: 8px;
}
.copy-row input {
  flex: 1;
  padding: 10px 12px;
  border: 1px solid var(--gsm-border);
  border-radius: var(--radius);
  font-size: 14px;
  font-family: Consolas, Monaco, monospace;
  background: var(--surface-2);
  color: var(--gsm-text);
  outline: none;
  min-width: 0;
}
.copy-row input:focus { border-color: var(--gsm-blue); }
.copy-row #share-url, .copy-row #share-code {
  font-weight: 600;
  color: var(--gsm-blue);
  letter-spacing: 0.04em;
}
.copy-row .copy-btn {
  padding: 0 16px;
  background: var(--gsm-blue-pale);
  color: var(--gsm-blue);
  font-weight: 700;
  border-radius: var(--radius);
  font-size: 13px;
  border: 1px solid var(--gsm-border);
  white-space: nowrap;
  transition: background .12s, color .12s;
}
.copy-row .copy-btn:hover { background: var(--gsm-blue); color: #fff; }
.copy-row .copy-btn.copied { background: var(--gsm-success); color: #fff; border-color: var(--gsm-success); }
.copy-row .cta-btn { padding: 10px 20px; font-size: 14px; }

.share-toast {
  position: fixed;
  bottom: 32px;
  left: 50%;
  transform: translateX(-50%) translateY(20px);
  background: var(--gsm-blue);
  color: #fff;
  padding: 12px 22px;
  border-radius: 10px;
  font-size: 14px;
  font-weight: 600;
  box-shadow: var(--shadow-lg);
  z-index: 200;
  opacity: 0;
  pointer-events: none;
  transition: opacity .2s, transform .2s;
}
.share-toast.show { opacity: 1; transform: translateX(-50%) translateY(0); }
.share-toast::before { content: '✓'; margin-right: 8px; font-weight: 700; }

.lang-toggle {
  display: inline-flex;
  background: var(--surface-2);
  border: 1px solid var(--gsm-border);
  border-radius: 999px;
  padding: 3px;
  gap: 2px;
}
.lang-btn {
  padding: 6px 14px;
  font-size: 12.5px;
  font-weight: 600;
  color: var(--gsm-muted);
  border-radius: 999px;
  letter-spacing: 0.02em;
  transition: background .15s, color .15s;
}
.lang-btn.active {
  background: var(--gsm-blue);
  color: #fff;
}
.lang-btn:not(.active):hover { color: var(--gsm-blue); }

.lo-badge {
  display: inline-flex;
  align-items: center;
  gap: 6px;
  margin-top: 2px;
  font-size: 11px;
  color: var(--gsm-blue);
  font-weight: 600;
  text-transform: uppercase;
  letter-spacing: 0.04em;
}
.lo-badge::before {
  content: '';
  width: 6px; height: 6px;
  border-radius: 50%;
  background: var(--gsm-success);
}

/* === Tab bar ============================================================ */

.tab-bar {
  background: var(--surface);
  border-bottom: 1px solid var(--gsm-border);
  padding: 0 24px;
  display: flex;
  gap: 4px;
  overflow-x: auto;
  position: sticky;
  top: 71px;
  z-index: 49;
}
.tab {
  padding: 14px 18px;
  font-size: 14px;
  font-weight: 600;
  color: var(--gsm-muted);
  border-bottom: 3px solid transparent;
  white-space: nowrap;
  transition: color .15s, border-color .15s;
}
.tab:hover { color: var(--gsm-blue); }
.tab.active {
  color: var(--gsm-blue);
  border-bottom-color: var(--gsm-blue);
}

/* === Main stage + panels ================================================ */

.calc-stage { padding: 28px 32px 64px; max-width: 1280px; margin: 0 auto; }
.calc-panel { display: none; }
.calc-panel.active { display: block; }

.panel-header {
  margin-bottom: 22px;
}
.panel-header h1 {
  margin: 0 0 4px;
  font-size: 28px;
  color: var(--gsm-blue);
  letter-spacing: -0.4px;
}
.panel-header p {
  margin: 0;
  color: var(--gsm-muted);
  font-size: 15px;
  max-width: 680px;
}

.calc-grid {
  display: grid;
  grid-template-columns: minmax(0, 380px) minmax(0, 1fr);
  gap: 24px;
}
@media (max-width: 880px) {
  .calc-grid { grid-template-columns: 1fr; }
}

.card {
  background: var(--surface);
  border: 1px solid var(--gsm-border);
  border-radius: var(--radius-lg);
  padding: 22px 24px;
  box-shadow: var(--shadow);
}
.card h2 {
  margin: 0 0 4px;
  font-size: 16px;
  color: var(--gsm-blue);
  text-transform: uppercase;
  letter-spacing: 0.08em;
}
.card h3 {
  margin: 18px 0 10px;
  font-size: 13px;
  color: var(--gsm-muted);
  text-transform: uppercase;
  letter-spacing: 0.06em;
}

/* === Inputs ============================================================= */

.field { margin-bottom: 14px; }
.field-label {
  display: flex; justify-content: space-between; align-items: baseline;
  font-size: 12px;
  color: var(--gsm-muted);
  text-transform: uppercase;
  letter-spacing: 0.05em;
  margin-bottom: 4px;
}
.field-hint { font-size: 11px; text-transform: none; letter-spacing: 0; }
.rate-note {
  display: flex;
  align-items: center;
  gap: 6px;
  margin-top: 6px;
  padding: 6px 10px;
  font-size: 11.5px;
  font-style: italic;
  color: var(--gsm-blue);
  background: var(--gsm-blue-pale);
  border-radius: 8px;
  line-height: 1.4;
}
.rate-note::before {
  content: '★';
  font-style: normal;
  font-size: 12px;
  color: var(--gsm-gold);
  flex-shrink: 0;
}
.input-wrap {
  position: relative;
  display: flex;
  align-items: center;
  background: var(--surface-2);
  border: 1px solid var(--gsm-border);
  border-radius: var(--radius);
  transition: border-color .15s;
}
.input-wrap:focus-within { border-color: var(--gsm-blue); }
.input-prefix, .input-suffix {
  padding: 0 10px;
  color: var(--gsm-muted);
  font-size: 14px;
  font-weight: 600;
}
.input-wrap input,
.input-wrap select {
  flex: 1;
  width: 100%;
  background: transparent;
  border: none;
  outline: none;
  padding: 10px 12px;
  font-size: 15px;
  color: var(--gsm-text);
  font-weight: 600;
}
.input-wrap input[type="number"] { -moz-appearance: textfield; }
.input-wrap input::-webkit-outer-spin-button,
.input-wrap input::-webkit-inner-spin-button {
  -webkit-appearance: none; margin: 0;
}

.field-row {
  display: grid;
  grid-template-columns: 1fr 1fr;
  gap: 10px;
}

.btn-group {
  display: flex;
  gap: 6px;
  background: var(--surface-2);
  border: 1px solid var(--gsm-border);
  border-radius: var(--radius);
  padding: 4px;
}
.btn-group button {
  flex: 1;
  padding: 8px 0;
  font-size: 13px;
  font-weight: 600;
  border-radius: 8px;
  color: var(--gsm-muted);
  transition: all .15s;
}
.btn-group button.active {
  background: var(--gsm-blue);
  color: #fff;
  box-shadow: var(--shadow);
}

.toggle-row {
  display: flex; align-items: center; gap: 10px;
  margin: 10px 0 6px;
  font-size: 13px;
  color: var(--gsm-muted);
}
.toggle-row input[type="checkbox"] {
  width: 18px; height: 18px;
  accent-color: var(--gsm-blue);
  cursor: pointer;
}

/* === Results ============================================================ */

.result-hero {
  display: flex;
  align-items: baseline;
  justify-content: space-between;
  gap: 12px;
  padding: 18px 22px;
  background: linear-gradient(135deg, var(--gsm-blue) 0%, var(--gsm-blue-light) 100%);
  color: #fff;
  border-radius: var(--radius);
  margin-bottom: 18px;
}
.result-hero-label {
  font-size: 12px;
  text-transform: uppercase;
  letter-spacing: 0.08em;
  opacity: 0.85;
}
.result-hero-value {
  font-size: 38px;
  font-weight: 800;
  letter-spacing: -1px;
}
.result-hero-sub { font-size: 13px; opacity: 0.85; }

.stat-grid {
  display: grid;
  grid-template-columns: repeat(auto-fit, minmax(160px, 1fr));
  gap: 12px;
  margin-bottom: 18px;
}
.stat {
  background: var(--surface-2);
  border: 1px solid var(--gsm-border);
  border-radius: var(--radius);
  padding: 12px 14px;
}
.stat-label {
  font-size: 11px;
  color: var(--gsm-muted);
  text-transform: uppercase;
  letter-spacing: 0.05em;
}
.stat-value {
  font-size: 19px;
  font-weight: 700;
  color: var(--gsm-text);
  margin-top: 2px;
}
.stat-sub { font-size: 12px; color: var(--gsm-muted); }
.stat.success .stat-value { color: var(--gsm-success); }
.stat.gold .stat-value { color: var(--gsm-gold); }

.chart-wrap {
  position: relative;
  height: 280px;
  margin: 14px 0;
}
.chart-wrap.tall { height: 340px; }
.chart-wrap.short { height: 180px; }

.split-charts {
  display: grid;
  grid-template-columns: minmax(0, 1fr) minmax(0, 1.2fr);
  gap: 18px;
  align-items: center;
}
@media (max-width: 720px) { .split-charts { grid-template-columns: 1fr; } }

.legend-grid {
  display: grid;
  grid-template-columns: 1fr auto;
  gap: 4px 16px;
  font-size: 13px;
}
.legend-grid .legend-key {
  display: flex; align-items: center; gap: 8px;
  color: var(--gsm-muted);
}
.legend-grid .legend-key::before {
  content: '';
  width: 10px; height: 10px;
  border-radius: 50%;
  background: var(--swatch, var(--gsm-blue));
}
.legend-grid .legend-val { font-weight: 700; text-align: right; }

/* === CTA ================================================================ */

.cta-row {
  margin-top: 22px;
  padding: 18px 22px;
  background: var(--gsm-blue-pale);
  border: 1px dashed var(--gsm-blue);
  border-radius: var(--radius);
  display: flex;
  align-items: center;
  justify-content: space-between;
  gap: 16px;
  flex-wrap: wrap;
}
.cta-row .cta-text {
  flex: 1; min-width: 200px;
  color: var(--gsm-text);
}
.cta-row .cta-text strong { color: var(--gsm-blue); }
.cta-btn {
  padding: 12px 24px;
  background: var(--gsm-blue);
  color: #fff;
  font-weight: 700;
  border-radius: 10px;
  font-size: 15px;
  box-shadow: var(--shadow);
  transition: transform .12s, background .12s;
}
.cta-btn:hover { background: var(--gsm-blue-dark); transform: translateY(-1px); }
.cta-btn.lg { padding: 14px 28px; font-size: 16px; }

/* === Amortization table ================================================= */

.table-wrap {
  margin-top: 18px;
  max-height: 320px;
  overflow: auto;
  border: 1px solid var(--gsm-border);
  border-radius: var(--radius);
}
.amort-table {
  width: 100%;
  border-collapse: collapse;
  font-size: 13px;
}
.amort-table th, .amort-table td {
  padding: 8px 12px;
  text-align: right;
  border-bottom: 1px solid var(--grid-line);
}
.amort-table th:first-child, .amort-table td:first-child { text-align: left; }
.amort-table thead th {
  background: var(--surface-2);
  position: sticky;
  top: 0;
  color: var(--gsm-muted);
  font-weight: 600;
  text-transform: uppercase;
  font-size: 11px;
  letter-spacing: 0.05em;
}
.amort-table tbody tr.year-end { background: var(--gsm-blue-pale); }
.amort-table tbody tr:hover { background: var(--row-hover); }

/* === Modal ============================================================== */

.modal-backdrop {
  position: fixed; inset: 0;
  background: rgba(10, 21, 37, 0.55);
  display: flex; align-items: center; justify-content: center;
  z-index: 100;
  padding: 20px;
  backdrop-filter: blur(2px);
}
.modal-backdrop[hidden] { display: none !important; }
.modal-card {
  background: var(--surface);
  border-radius: var(--radius-lg);
  max-width: 460px;
  width: 100%;
  padding: 28px 28px 22px;
  box-shadow: var(--shadow-lg);
  position: relative;
}
.modal-card h2 {
  margin: 0 0 4px;
  font-size: 22px;
  color: var(--gsm-blue);
}
.modal-card .muted { font-size: 14px; margin: 0 0 18px; }
.modal-close {
  position: absolute;
  top: 14px; right: 14px;
  width: 30px; height: 30px;
  border-radius: 50%;
  font-size: 18px;
  color: var(--gsm-muted);
  background: var(--surface-2);
}
.modal-close:hover { background: var(--row-hover); }

.honeypot {
  position: absolute;
  left: -9999px;
  width: 1px; height: 1px;
  opacity: 0;
}

.form-msg {
  margin-top: 12px;
  padding: 10px 14px;
  border-radius: 10px;
  font-size: 13px;
  display: none;
}
.form-msg.show { display: block; }
.form-msg.ok { background: rgba(40, 167, 69, 0.12); color: var(--gsm-success); }
.form-msg.err { background: rgba(220, 53, 69, 0.12); color: var(--gsm-danger); }

/* === Footer ============================================================= */

.footer {
  padding: 30px 32px;
  text-align: center;
  color: var(--gsm-muted);
  font-size: 12px;
  border-top: 1px solid var(--gsm-border);
  background: var(--surface);
  margin-top: 40px;
}
.footer a { color: var(--gsm-blue); text-decoration: none; }
.footer .disclaimer { max-width: 720px; margin: 8px auto 0; line-height: 1.5; }

/* === Info tooltips ====================================================== */

.info {
  display: inline-flex;
  align-items: center;
  justify-content: center;
  width: 16px;
  height: 16px;
  padding: 0;
  border-radius: 50%;
  background: var(--gsm-blue-pale);
  color: var(--gsm-blue);
  font-family: Georgia, "Times New Roman", serif;
  font-size: 11px;
  font-style: italic;
  font-weight: 700;
  line-height: 1;
  border: 1px solid var(--gsm-blue);
  margin-left: 5px;
  vertical-align: -2px;
  cursor: help;
  transition: background .12s, color .12s;
}
.info:hover, .info:focus-visible, .info.open {
  background: var(--gsm-blue);
  color: #fff;
  outline: none;
}
.stat-label .info, .result-hero-label .info {
  border-color: currentColor;
  background: transparent;
  color: inherit;
  opacity: 0.65;
}
.stat-label .info:hover, .result-hero-label .info:hover { opacity: 1; }
.result-hero-label .info { border-color: rgba(255,255,255,.6); }

.tip-pop {
  position: absolute;
  z-index: 200;
  max-width: 280px;
  background: var(--surface);
  border: 1px solid var(--gsm-border);
  border-radius: 10px;
  padding: 10px 14px;
  font-size: 12.5px;
  line-height: 1.5;
  color: var(--gsm-text);
  font-weight: 400;
  text-transform: none;
  letter-spacing: 0;
  box-shadow: var(--shadow-lg);
  pointer-events: auto;
}
.tip-pop[hidden] { display: none; }
.tip-pop::before {
  content: '';
  position: absolute;
  width: 10px;
  height: 10px;
  background: var(--surface);
  border-left: 1px solid var(--gsm-border);
  border-top: 1px solid var(--gsm-border);
  transform: rotate(45deg);
  top: -6px;
  left: var(--arrow-left, 18px);
}
.tip-pop.above::before {
  top: auto;
  bottom: -6px;
  transform: rotate(225deg);
}

/* === Misc =============================================================== */

.pill {
  display: inline-block;
  padding: 2px 10px;
  border-radius: 999px;
  font-size: 11px;
  font-weight: 700;
  background: var(--gsm-blue-pale);
  color: var(--gsm-blue);
  letter-spacing: 0.04em;
  text-transform: uppercase;
}
.pill.gold   { background: rgba(212,169,59,0.15); color: var(--gsm-gold); }
.pill.green  { background: rgba(40,167,69,0.13); color: var(--gsm-success); }
.pill.red    { background: rgba(220,53,69,0.13); color: var(--gsm-danger); }

.divider {
  height: 1px;
  background: var(--gsm-border);
  margin: 16px 0;
}

@media (max-width: 600px) {
  .topbar { padding: 12px 16px; flex-wrap: wrap; }
  .brand-title { font-size: 14px; }
  .rate-badge { min-width: 0; padding: 6px 12px; }
  .rate-value { font-size: 18px; }
  .calc-stage { padding: 20px 14px 48px; }
  .panel-header h1 { font-size: 22px; }
  .result-hero-value { font-size: 30px; }
  .tab-bar { padding: 0 12px; top: 88px; }
}