/* ── Base ─────────────────────────────────────────────────────────────── */
:root {
  --color-bg:          #f4f6f9;
  --color-surface:     #ffffff;
  --color-surface-alt: #f8f9fb;
  --color-border:      #e2e6ea;
  --color-text:        #1a1d23;
  --color-text-muted:  #6b7280;
  --color-accent:      #4f6ef7;
  --color-accent-hover:#3a58e0;
  --color-green:       #22c55e;
  --color-blue:        #3b82f6;
  --radius:            12px;
  --radius-sm:         8px;
  --shadow:            0 1px 3px rgba(0,0,0,.08), 0 4px 16px rgba(0,0,0,.06);
  --shadow-lg:         0 4px 6px rgba(0,0,0,.07), 0 10px 40px rgba(0,0,0,.1);
  --transition:        180ms ease;
}

@media (prefers-color-scheme: dark) {
  :root {
    --color-bg:          #0f1117;
    --color-surface:     #1a1d27;
    --color-surface-alt: #21242f;
    --color-border:      #2d3141;
    --color-text:        #e8eaf0;
    --color-text-muted:  #8b92a5;
    --color-accent:      #6c8aff;
    --color-accent-hover:#849dff;
    --shadow:            0 1px 3px rgba(0,0,0,.3), 0 4px 16px rgba(0,0,0,.25);
    --shadow-lg:         0 4px 6px rgba(0,0,0,.3), 0 10px 40px rgba(0,0,0,.4);
  }
}

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

html { scroll-behavior: smooth; }

body {
  background: var(--color-bg);
  color: var(--color-text);
  font-family: -apple-system, BlinkMacSystemFont, "Segoe UI", Roboto, "Helvetica Neue", Arial, sans-serif;
  font-size: 1rem;
  line-height: 1.6;
  -webkit-font-smoothing: antialiased;
}

/* ── Layout ──────────────────────────────────────────────────────────── */
.app-container {
  max-width: 900px;
  margin: 0 auto;
  padding: 2rem 1rem 4rem;
}

/* ── App header ──────────────────────────────────────────────────────── */
.app-header {
  text-align: center;
  padding: 3rem 1rem 2rem;
}

.app-header h1 {
  font-size: clamp(1.8rem, 4vw, 2.8rem);
  font-weight: 800;
  letter-spacing: -0.03em;
  color: var(--color-text);
  margin: 0 0 0.5rem;
}

.app-header p {
  color: var(--color-text-muted);
  font-size: 1.05rem;
  margin: 0;
}

/* ── Cards ───────────────────────────────────────────────────────────── */
.panel {
  background: var(--color-surface);
  border: 1px solid var(--color-border);
  border-radius: var(--radius);
  box-shadow: var(--shadow);
  padding: 2rem;
  margin-bottom: 1.5rem;
}

/* ── Section label ───────────────────────────────────────────────────── */
.section-label {
  font-size: 0.7rem;
  font-weight: 700;
  letter-spacing: 0.1em;
  text-transform: uppercase;
  color: var(--color-text-muted);
  margin: 0 0 1.25rem;
}

/* ── Form grid ───────────────────────────────────────────────────────── */
.form-grid {
  display: grid;
  grid-template-columns: 1fr 1fr;
  gap: 1rem;
}

@media (max-width: 540px) {
  .form-grid { grid-template-columns: 1fr; }
}

.field label {
  display: block;
  font-size: 0.85rem;
  font-weight: 600;
  color: var(--color-text-muted);
  margin-bottom: 0.4rem;
}

.field input {
  width: 100%;
  padding: 0.65rem 0.9rem;
  font-size: 1rem;
  color: var(--color-text);
  background: var(--color-surface-alt);
  border: 1.5px solid var(--color-border);
  border-radius: var(--radius-sm);
  outline: none;
  transition: border-color var(--transition), box-shadow var(--transition);
  -moz-appearance: textfield;
}

.field input::-webkit-outer-spin-button,
.field input::-webkit-inner-spin-button {
  -webkit-appearance: none;
  margin: 0;
}

.field input::placeholder { color: var(--color-text-muted); opacity: 0.6; }

.field input:focus {
  border-color: var(--color-accent);
  box-shadow: 0 0 0 3px color-mix(in srgb, var(--color-accent) 20%, transparent);
}

/* ── Divider ─────────────────────────────────────────────────────────── */
.divider {
  display: flex;
  align-items: center;
  gap: 0.75rem;
  margin: 1.75rem 0;
  color: var(--color-text-muted);
  font-size: 0.8rem;
  font-weight: 600;
  letter-spacing: 0.05em;
  text-transform: uppercase;
}

.divider::before,
.divider::after {
  content: "";
  flex: 1;
  height: 1px;
  background: var(--color-border);
}

/* ── Submit columns ──────────────────────────────────────────────────── */
.submit-grid {
  display: grid;
  grid-template-columns: 1fr 1fr;
  gap: 1rem;
}

@media (max-width: 540px) {
  .submit-grid { grid-template-columns: 1fr; }
}

.submit-group label {
  display: block;
  font-size: 0.85rem;
  font-weight: 600;
  color: var(--color-text-muted);
  margin-bottom: 0.4rem;
}

.submit-group input {
  width: 100%;
  padding: 0.65rem 0.9rem;
  font-size: 1rem;
  color: var(--color-text);
  background: var(--color-surface-alt);
  border: 1.5px solid var(--color-border);
  border-radius: var(--radius-sm);
  outline: none;
  transition: border-color var(--transition), box-shadow var(--transition);
  -moz-appearance: textfield;
}

.submit-group input::-webkit-outer-spin-button,
.submit-group input::-webkit-inner-spin-button {
  -webkit-appearance: none;
  margin: 0;
}

.submit-group input::placeholder { color: var(--color-text-muted); opacity: 0.6; }

.submit-group input:focus {
  border-color: var(--color-accent);
  box-shadow: 0 0 0 3px color-mix(in srgb, var(--color-accent) 20%, transparent);
}

/* ── Buttons ─────────────────────────────────────────────────────────── */
.btn-primary {
  display: block;
  width: 100%;
  margin-top: 0.75rem;
  padding: 0.7rem 1rem;
  font-size: 0.95rem;
  font-weight: 600;
  color: #fff;
  background: var(--color-accent);
  border: none;
  border-radius: var(--radius-sm);
  cursor: pointer;
  transition: background var(--transition), transform var(--transition), box-shadow var(--transition);
}

.btn-primary:hover {
  background: var(--color-accent-hover);
  box-shadow: 0 4px 12px color-mix(in srgb, var(--color-accent) 35%, transparent);
  transform: translateY(-1px);
}

.btn-primary:active {
  transform: translateY(0);
  box-shadow: none;
}

.btn-primary:focus-visible {
  outline: 3px solid var(--color-accent);
  outline-offset: 2px;
}

/* ── Charts panel ────────────────────────────────────────────────────── */
#graphCard {
  display: none;
}

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

@media (max-width: 640px) {
  .chart-grid { grid-template-columns: 1fr; }
}

.chartContainer {
  border-radius: var(--radius-sm);
  overflow: hidden;
}

/* ── Tables ──────────────────────────────────────────────────────────── */
.table-section {
  display: none;
  margin-top: 1.5rem;
}

.table-section h2 {
  font-size: 1rem;
  font-weight: 700;
  letter-spacing: -0.01em;
  color: var(--color-text);
  margin: 0 0 0.75rem;
}

.data-table {
  width: 100%;
  border-collapse: collapse;
  font-size: 0.9rem;
}

.data-table th {
  padding: 0.6rem 0.9rem;
  text-align: left;
  font-size: 0.75rem;
  font-weight: 700;
  letter-spacing: 0.06em;
  text-transform: uppercase;
  color: var(--color-text-muted);
  background: var(--color-surface-alt);
  border-bottom: 1px solid var(--color-border);
}

.data-table td {
  padding: 0.55rem 0.9rem;
  color: var(--color-text);
  border-bottom: 1px solid var(--color-border);
}

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

.data-table tbody tr:hover { background: var(--color-surface-alt); }