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

:root {
  --blue: #185FA5;
  --blue-light: #e8f0f9;
  --border: #e2e6ea;
  --text: #1a1a1a;
  --muted: #6b7280;
  --bg: #f5f7fa;
  --white: #ffffff;
  --red: #dc2626;
  --success: #16a34a;
}

body {
  font-family: 'Inter', system-ui, -apple-system, sans-serif;
  font-size: 14px;
  color: var(--text);
  background: var(--bg);
  line-height: 1.5;
}

/* ── Header brand + link ── */
.header-brand {
  display: flex;
  align-items: center;
  gap: 20px;
  flex-shrink: 0;
}

.header-link {
  font-size: 13px;
  font-weight: 500;
  color: var(--muted);
  text-decoration: none;
  transition: color 0.15s;
}

.header-link:hover { color: var(--blue); }

/* ── Tab FREE badge ── */
.tab-badge {
  display: inline-block;
  background: #16a34a;
  color: #fff;
  font-size: 10px;
  font-weight: 700;
  letter-spacing: .04em;
  padding: 1px 6px;
  border-radius: 99px;
  margin-left: 5px;
  vertical-align: middle;
  line-height: 1.6;
}

/* ── Header ── */
.site-header {
  background: var(--white);
  border-bottom: 1px solid var(--border);
  position: sticky;
  top: 0;
  z-index: 100;
}

.header-inner {
  max-width: 1100px;
  margin: 0 auto;
  padding: 0 24px;
  display: flex;
  align-items: center;
  gap: 32px;
  height: 56px;
}

.site-name {
  font-size: 18px;
  font-weight: 700;
  color: var(--blue);
  letter-spacing: -0.5px;
  white-space: nowrap;
}

.tab-nav {
  display: flex;
  gap: 4px;
}

.tab-btn {
  background: none;
  border: none;
  padding: 8px 16px;
  font-size: 14px;
  font-weight: 500;
  color: var(--muted);
  cursor: pointer;
  border-radius: 6px;
  transition: background 0.15s, color 0.15s;
}

.tab-btn:hover { background: var(--blue-light); color: var(--blue); }
.tab-btn.active { background: var(--blue-light); color: var(--blue); }

/* ── Tab panels ── */
.tab-panel { display: none; }
.tab-panel.active { display: block; }

.panel-inner {
  max-width: 1100px;
  margin: 0 auto;
  padding: 24px;
  display: flex;
  flex-direction: column;
  gap: 16px;
}

/* ── Cards ── */
.card {
  background: var(--white);
  border: 1px solid var(--border);
  border-radius: 10px;
  padding: 20px 24px;
}

.section-title {
  font-size: 15px;
  font-weight: 600;
  color: var(--blue);
  margin-bottom: 14px;
}

.section-hint {
  font-size: 13px;
  color: var(--muted);
  line-height: 1.5;
  margin-bottom: 14px;
}

/* ── Dropzone ── */
.dropzone {
  border: 2px dashed var(--border);
  border-radius: 8px;
  padding: 32px;
  text-align: center;
  cursor: pointer;
  transition: border-color 0.15s, background 0.15s;
}

.dropzone:hover, .dropzone.drag-over {
  border-color: var(--blue);
  background: var(--blue-light);
}

.drop-inner { display: flex; flex-direction: column; align-items: center; gap: 10px; }
.drop-inner p { color: var(--muted); }
.browse-link { color: var(--blue); cursor: pointer; text-decoration: underline; }

.upload-status {
  margin-top: 12px;
  padding: 10px 14px;
  border-radius: 6px;
  font-size: 13px;
}

.upload-status.success { background: #f0fdf4; border: 1px solid #bbf7d0; color: var(--success); }
.upload-status.error   { background: #fef2f2; border: 1px solid #fecaca; color: var(--red); }
.upload-status.loading { background: var(--blue-light); border: 1px solid #bfdbfe; color: var(--blue); }

/* ── Toggle group ── */
.toggle-group {
  display: flex;
  gap: 4px;
  margin-bottom: 14px;
}

.toggle-btn {
  background: none;
  border: 1px solid var(--border);
  border-radius: 6px;
  padding: 7px 16px;
  font-size: 13px;
  font-weight: 500;
  color: var(--muted);
  cursor: pointer;
  transition: all 0.15s;
}

.toggle-btn:hover { border-color: var(--blue); color: var(--blue); }
.toggle-btn.active { background: var(--blue); border-color: var(--blue); color: var(--white); }

/* ── Param row ── */
.param-row {
  display: flex;
  flex-wrap: wrap;
  gap: 16px;
  align-items: flex-end;
}

.param-label {
  display: flex;
  flex-direction: column;
  gap: 4px;
  font-size: 13px;
  font-weight: 500;
  color: var(--muted);
}

.unit { font-weight: 400; color: var(--muted); font-size: 12px; }

.param-input {
  width: 120px;
  padding: 8px 10px;
  border: 1px solid var(--border);
  border-radius: 6px;
  font-size: 14px;
  color: var(--text);
  background: var(--white);
  transition: border-color 0.15s;
}

.param-input:focus {
  outline: none;
  border-color: var(--blue);
}

/* ── Model tabs ── */
.model-tabs {
  display: flex;
  flex-wrap: wrap;
  gap: 4px;
  margin-bottom: 14px;
}

.model-tab {
  background: none;
  border: 1px solid var(--border);
  border-radius: 6px;
  padding: 6px 14px;
  font-size: 13px;
  font-weight: 500;
  color: var(--muted);
  cursor: pointer;
  transition: all 0.15s;
}

.model-tab:hover { border-color: var(--blue); color: var(--blue); }
.model-tab.active { background: var(--blue); border-color: var(--blue); color: var(--white); }

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

.formula {
  font-family: 'Georgia', serif;
  font-size: 15px;
  color: var(--text);
  margin-bottom: 12px;
}

.readonly-note {
  font-size: 12px;
  color: var(--muted);
  font-style: italic;
}

/* ── Run section ── */
.run-section { text-align: right; }

/* ── Buttons ── */
.btn-primary {
  background: var(--blue);
  color: var(--white);
  border: none;
  border-radius: 7px;
  padding: 10px 24px;
  font-size: 14px;
  font-weight: 600;
  cursor: pointer;
  transition: opacity 0.15s;
}

.btn-primary:hover:not(:disabled) { opacity: 0.88; }
.btn-primary:disabled { opacity: 0.4; cursor: not-allowed; }

.btn-secondary {
  background: var(--white);
  color: var(--blue);
  border: 1px solid var(--blue);
  border-radius: 7px;
  padding: 7px 16px;
  font-size: 13px;
  font-weight: 500;
  cursor: pointer;
  transition: background 0.15s;
}

.btn-secondary:hover { background: var(--blue-light); }

.btn-remove {
  background: none;
  border: none;
  color: var(--muted);
  font-size: 18px;
  cursor: pointer;
  padding: 0 6px;
  line-height: 1;
}

.btn-remove:hover { color: var(--red); }

/* ── Summary grid ── */
.summary-grid {
  display: grid;
  grid-template-columns: repeat(auto-fit, minmax(160px, 1fr));
  gap: 12px;
}

.summary-card {
  border: 1px solid var(--border);
  border-radius: 8px;
  padding: 14px 16px;
}

.metric-label { font-size: 12px; color: var(--muted); margin-bottom: 4px; }
.metric-value { font-size: 20px; font-weight: 700; color: var(--text); }

/* ── Chart ── */
.chart-header {
  display: flex;
  align-items: center;
  justify-content: space-between;
  flex-wrap: wrap;
  gap: 8px;
  margin-bottom: 14px;
}

.chart-actions { display: flex; gap: 8px; flex-wrap: wrap; }

.chart-wrap {
  position: relative;
  width: 100%;
  height: 300px;
}

.chart-wrap canvas { width: 100% !important; height: 100% !important; }

/* ── Bouts table ── */
.bouts-table {
  width: 100%;
  border-collapse: collapse;
  font-size: 13px;
}

.bouts-table th {
  text-align: left;
  padding: 8px 10px;
  color: var(--muted);
  font-weight: 500;
  border-bottom: 1px solid var(--border);
}

.bouts-table td {
  padding: 6px 8px;
  border-bottom: 1px solid var(--border);
}

.bout-input {
  width: 100%;
  padding: 6px 8px;
  border: 1px solid var(--border);
  border-radius: 5px;
  font-size: 13px;
}

.bout-input:focus { outline: none; border-color: var(--blue); }

/* ── W′ERG display ── */
.werg-row {
  display: flex;
  align-items: baseline;
  gap: 10px;
  margin-top: 14px;
  padding: 10px 14px;
  background: var(--blue-light);
  border: 1px solid #bfdbfe;
  border-radius: 7px;
  flex-wrap: wrap;
}

.werg-label { font-size: 13px; font-weight: 600; color: var(--blue); white-space: nowrap; }
.werg-value { font-size: 18px; font-weight: 700; color: var(--blue); }
.werg-hint  { font-size: 12px; color: var(--muted); }

.trial-role {
  font-size: 12px;
  padding: 4px 6px;
  border: 1px solid var(--border);
  border-radius: 5px;
  background: var(--white);
  cursor: pointer;
}

.trial-role:focus { outline: none; border-color: var(--blue); }

/* ── Trial detail panel ── */
.trial-detail-panel {
  background: var(--bg);
  border: 1px solid var(--border);
  border-radius: 8px;
  padding: 12px;
  margin-top: 4px;
}

.trial-range-row {
  display: flex;
  align-items: center;
  gap: 14px;
  flex-wrap: wrap;
  margin-top: 10px;
}

.range-input {
  width: 72px;
  padding: 5px 8px;
  border: 1px solid var(--border);
  border-radius: 5px;
  font-size: 13px;
}

.range-input:focus { outline: none; border-color: var(--blue); }

/* ── Fit results ── */
.fit-constants {
  display: flex;
  gap: 24px;
  flex-wrap: wrap;
  margin-bottom: 10px;
}

.fit-const-item { font-size: 15px; font-weight: 600; }
.fit-const-item span { font-weight: 400; color: var(--muted); }

.rmse-line { font-size: 13px; color: var(--muted); margin-bottom: 14px; }

/* ── Utilities ── */
.hidden { display: none !important; }

/* ── Responsive ── */
@media (max-width: 640px) {
  .header-inner { flex-direction: column; height: auto; padding: 12px 16px; gap: 8px; }
  .panel-inner { padding: 12px; }
  .card { padding: 16px; }
  .param-input { width: 100px; }
  .chart-wrap { height: 220px; }
  .chart-header { flex-direction: column; align-items: flex-start; }
}