/* ============================================================
   road_stat — main stylesheet
   Font stack: system-ui with Cyrillic fallback
   ============================================================ */

:root {
  --color-bg:          #f5f6f8;
  --color-surface:     #ffffff;
  --color-border:      #d0d5de;
  --color-primary:     #2563eb;
  --color-primary-dk:  #1d4ed8;
  --color-accent:      #0ea5e9;
  --color-text:        #1e293b;
  --color-text-muted:  #64748b;
  --color-success:     #16a34a;
  --color-warn:        #d97706;
  --color-danger:      #dc2626;
  --color-hint-bg:     #eff6ff;
  --color-hint-border: #bfdbfe;
  --radius:            8px;
  --shadow-sm:         0 1px 3px rgba(0,0,0,.08);
  --shadow-md:         0 4px 12px rgba(0,0,0,.12);
  --transition:        180ms ease;
  --max-width:         960px;
}

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

html { font-size: 16px; scroll-behavior: smooth; }

body {
  font-family: "Segoe UI", system-ui, -apple-system, sans-serif;
  background: var(--color-bg);
  color: var(--color-text);
  line-height: 1.55;
  min-height: 100vh;
}

/* ── Header ─────────────────────────────────────────────── */
.site-header {
  background: var(--color-primary);
  color: #fff;
  padding: 0.75rem 1.5rem;
  display: flex;
  align-items: center;
  gap: 1rem;
  box-shadow: var(--shadow-sm);
}
.site-header h1 { font-size: 1.15rem; font-weight: 600; letter-spacing: .01em; }
.site-header .subtitle { font-size: .85rem; opacity: .85; }

/* ── Page layout ─────────────────────────────────────────── */
.page-wrapper {
  max-width: var(--max-width);
  margin: 2rem auto;
  padding: 0 1rem;
}

/* ── Card / section ──────────────────────────────────────── */
.card {
  background: var(--color-surface);
  border: 1px solid var(--color-border);
  border-radius: var(--radius);
  box-shadow: var(--shadow-sm);
  padding: 1.5rem 2rem;
  margin-bottom: 1.5rem;
}
.card h2 {
  font-size: 1rem;
  font-weight: 600;
  color: var(--color-primary);
  text-transform: uppercase;
  letter-spacing: .05em;
  margin-bottom: 1.25rem;
  padding-bottom: .5rem;
  border-bottom: 2px solid var(--color-hint-border);
}

/* ── Form grid ───────────────────────────────────────────── */
.form-grid {
  display: grid;
  grid-template-columns: repeat(auto-fill, minmax(260px, 1fr));
  gap: 1rem 1.5rem;
}

.field {
  display: flex;
  flex-direction: column;
  gap: .35rem;
}

.field label {
  font-size: .875rem;
  font-weight: 500;
  display: flex;
  align-items: center;
  gap: .4rem;
}

.field input[type="text"],
.field input[type="number"],
.field input[type="date"],
.field input[type="time"],
.field select,
.field textarea {
  border: 1px solid var(--color-border);
  border-radius: calc(var(--radius) - 2px);
  padding: .45rem .75rem;
  font-size: .9rem;
  font-family: inherit;
  color: var(--color-text);
  background: #fff;
  transition: border-color var(--transition), box-shadow var(--transition);
  width: 100%;
}
.field input:focus,
.field select:focus,
.field textarea:focus {
  outline: none;
  border-color: var(--color-primary);
  box-shadow: 0 0 0 3px rgba(37,99,235,.15);
}
.field input[type="number"] { appearance: textfield; }

/* vehicle counts table */
.vehicle-table {
  width: 100%;
  border-collapse: collapse;
  font-size: .875rem;
}
.vehicle-table th {
  text-align: left;
  font-weight: 500;
  color: var(--color-text-muted);
  padding: .4rem .5rem;
  border-bottom: 1px solid var(--color-border);
}
.vehicle-table td { padding: .35rem .5rem; }
.vehicle-table td input[type="number"] {
  width: 90px;
  border: 1px solid var(--color-border);
  border-radius: 4px;
  padding: .3rem .5rem;
  font-size: .875rem;
}

/* run-times dynamic list */
.run-times-list { display: flex; flex-direction: column; gap: .4rem; }
.run-time-row { display: flex; align-items: center; gap: .5rem; }
.run-time-row input { width: 120px; }
.btn-icon {
  background: none; border: none; cursor: pointer;
  color: var(--color-text-muted); font-size: 1rem; padding: .2rem;
  transition: color var(--transition);
}
.btn-icon:hover { color: var(--color-danger); }
.btn-add {
  align-self: flex-start;
  font-size: .8rem;
  color: var(--color-primary);
  background: none;
  border: 1px dashed var(--color-primary);
  border-radius: 4px;
  padding: .25rem .6rem;
  cursor: pointer;
  transition: background var(--transition);
}
.btn-add:hover { background: var(--color-hint-bg); }

/* ── Hint widget ─────────────────────────────────────────── */
.hint-inline {
  font-size: .8rem;
  color: var(--color-text-muted);
  background: var(--color-hint-bg);
  border-left: 3px solid var(--color-accent);
  padding: .3rem .6rem;
  border-radius: 0 4px 4px 0;
  line-height: 1.4;
}
.hint-trigger {
  display: inline-flex;
  align-items: center;
  justify-content: center;
  width: 16px; height: 16px;
  border-radius: 50%;
  background: var(--color-accent);
  color: #fff;
  font-size: .65rem;
  font-weight: 700;
  cursor: pointer;
  user-select: none;
  flex-shrink: 0;
  transition: background var(--transition);
  border: none;
}
.hint-trigger:hover { background: var(--color-primary); }

/* "don't know" checkbox */
.unknown-toggle {
  display: flex;
  align-items: center;
  gap: .4rem;
  font-size: .8rem;
  color: var(--color-text-muted);
  cursor: pointer;
  margin-top: .15rem;
}
.unknown-toggle input[type="checkbox"] { accent-color: var(--color-primary); }
.field.is-unknown input,
.field.is-unknown select {
  opacity: .4;
  pointer-events: none;
}

/* ── Submit button ───────────────────────────────────────── */
.btn-primary {
  background: var(--color-primary);
  color: #fff;
  border: none;
  border-radius: var(--radius);
  padding: .65rem 1.75rem;
  font-size: 1rem;
  font-weight: 600;
  cursor: pointer;
  transition: background var(--transition), transform var(--transition);
  box-shadow: var(--shadow-sm);
}
.btn-primary:hover  { background: var(--color-primary-dk); transform: translateY(-1px); }
.btn-primary:active { transform: translateY(0); }

/* ── Results tabs ────────────────────────────────────────── */
.tabs-nav {
  display: flex;
  gap: .25rem;
  border-bottom: 2px solid var(--color-border);
  margin-bottom: 1.5rem;
  flex-wrap: wrap;
}
.tab-btn {
  background: none;
  border: none;
  padding: .55rem 1.1rem;
  font-size: .9rem;
  font-weight: 500;
  color: var(--color-text-muted);
  cursor: pointer;
  border-bottom: 3px solid transparent;
  margin-bottom: -2px;
  transition: color var(--transition), border-color var(--transition);
  white-space: nowrap;
}
.tab-btn:hover  { color: var(--color-primary); }
.tab-btn.active { color: var(--color-primary); border-bottom-color: var(--color-primary); }

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

/* ── Results table ───────────────────────────────────────── */
.results-table {
  width: 100%;
  border-collapse: collapse;
  font-size: .9rem;
}
.results-table th {
  text-align: left;
  background: var(--color-hint-bg);
  color: var(--color-text-muted);
  font-weight: 500;
  padding: .5rem .75rem;
  border-bottom: 1px solid var(--color-border);
}
.results-table td {
  padding: .55rem .75rem;
  border-bottom: 1px solid var(--color-border);
  vertical-align: middle;
}
.results-table tr:last-child td { border-bottom: none; }
.result-value { font-weight: 600; color: var(--color-text); }
.result-unit  { color: var(--color-text-muted); font-size: .8rem; }

/* LOS badge */
.los-badge {
  display: inline-block;
  padding: .15rem .5rem;
  border-radius: 4px;
  font-weight: 700;
  font-size: .85rem;
}
.los-A { background: #dcfce7; color: #15803d; }
.los-B { background: #d1fae5; color: #047857; }
.los-C { background: #fef9c3; color: #854d0e; }
.los-D { background: #ffedd5; color: #c2410c; }
.los-E { background: #fee2e2; color: #b91c1c; }
.los-F { background: #fecaca; color: #991b1b; }

/* ── Download buttons ────────────────────────────────────── */
.download-row {
  display: flex;
  gap: 1rem;
  flex-wrap: wrap;
  margin-top: 1.25rem;
}
.btn-download {
  font-size: .85rem;
  color: var(--color-primary);
  background: none;
  border: 1px solid var(--color-primary);
  border-radius: var(--radius);
  padding: .4rem .9rem;
  cursor: pointer;
  transition: background var(--transition);
  text-decoration: none;
}
.btn-download:hover { background: var(--color-hint-bg); }

/* ── Modal (for long hints) ──────────────────────────────── */
.modal-overlay {
  display: none;
  position: fixed;
  inset: 0;
  background: rgba(0,0,0,.45);
  z-index: 1000;
  align-items: center;
  justify-content: center;
  padding: 1rem;
}
.modal-overlay.open { display: flex; }
.modal-box {
  background: var(--color-surface);
  border-radius: var(--radius);
  box-shadow: var(--shadow-md);
  padding: 1.75rem 2rem;
  max-width: 680px;
  width: 100%;
  max-height: 85vh;
  overflow-y: auto;
  position: relative;
}
.modal-close {
  position: absolute;
  top: .75rem; right: .75rem;
  background: none; border: none;
  font-size: 1.3rem; cursor: pointer;
  color: var(--color-text-muted);
  line-height: 1;
}
.modal-close:hover { color: var(--color-text); }
.modal-title {
  font-size: 1rem;
  font-weight: 600;
  margin-bottom: 1rem;
  color: var(--color-primary);
}
.modal-body {
  font-size: .9rem;
  line-height: 1.7;
  color: var(--color-text);
}
.modal-body p  { margin-bottom: .75rem; }
.modal-body table { border-collapse: collapse; width: 100%; margin: .75rem 0; font-size: .85rem; }
.modal-body th { background: var(--color-hint-bg); padding: .35rem .6rem; border: 1px solid var(--color-border); }
.modal-body td { padding: .35rem .6rem; border: 1px solid var(--color-border); }

/* ── Responsive tweaks ───────────────────────────────────── */
@media (max-width: 600px) {
  .card { padding: 1rem; }
  .form-grid { grid-template-columns: 1fr; }
  .page-wrapper { margin: 1rem auto; }
}