/* ================================================================
   Metabolic Age — Academic stylesheet
   Color palette:
     --navy:        #1e3a5f  (primary brand / section headers)
     --navy-light:  #2a4a7f  (hover states)
     --gray-light:  #f5f6f8  (page tint / footer)
     --border:      #dee2e6  (dividers)
     --text-muted:  #6c757d  (secondary text)
   ================================================================ */

/* ── Reset / base ─────────────────────────────────────────────── */
:root {
  --navy:       #1e3a5f;
  --navy-light: #2a4a7f;
  --gray-light: #f5f6f8;
  --border:     #dee2e6;
  --text-muted: #6c757d;
}

body {
  font-family: -apple-system, BlinkMacSystemFont, "Segoe UI", Roboto,
               "Helvetica Neue", Arial, sans-serif;
  font-size: 0.95rem;
  background-color: #ffffff;
  color: #212529;
}

/* ── Navbar ───────────────────────────────────────────────────── */
.navbar {
  background-color: #ffffff !important;
  border-bottom: 1px solid var(--border);
  padding-top: 0.6rem;
  padding-bottom: 0.6rem;
  margin-bottom: 0;
}

.navbar-brand {
  font-weight: 700;
  font-size: 1.1rem;
  color: var(--navy) !important;
  letter-spacing: 0.01em;
}

.navbar-nav .nav-link {
  color: #343a40 !important;
  font-size: 0.9rem;
  padding-left: 0.85rem;
  padding-right: 0.85rem;
}

.navbar-nav .nav-link:hover {
  color: var(--navy) !important;
}

.btn-nav-register {
  font-size: 0.85rem;
  padding: 0.3rem 0.9rem;
  border-radius: 3px;
  color: #fff !important;
}

.navbar-nav .nav-link.btn-nav-register,
.navbar-nav .nav-link.btn-nav-register:hover {
  color: #fff !important;
}

/* ── Page content spacing ─────────────────────────────────────── */
.page-content {
  padding-top: 2rem;
  padding-bottom: 3rem;
}

/* ── Section / card headers (dark navy banner) ────────────────── */
.section-header {
  background-color: var(--navy);
  color: #ffffff;
  padding: 0.55rem 1rem;
  font-size: 0.9rem;
  font-weight: 600;
  letter-spacing: 0.02em;
  border-radius: 0;
}

/* Override Bootstrap card-header inside .card to match */
.card > .card-header {
  background-color: var(--navy);
  color: #ffffff;
  font-size: 0.9rem;
  font-weight: 600;
  border-bottom: none;
  border-radius: 0 !important;
  padding: 0.55rem 1rem;
}

/* ── Cards ────────────────────────────────────────────────────── */
.card {
  border: 1px solid var(--border);
  border-radius: 3px;
  box-shadow: 0 1px 3px rgba(0, 0, 0, 0.06);
}

.card-body {
  padding: 1.25rem;
}

/* ── Buttons ──────────────────────────────────────────────────── */
.btn-primary {
  background-color: var(--navy);
  border-color: var(--navy);
  border-radius: 3px;
  color: #fff;
}

.btn-primary:hover,
.btn-primary:focus {
  background-color: var(--navy-light);
  border-color: var(--navy-light);
  color: #fff;
}

.btn-outline-primary {
  color: var(--navy);
  border-color: var(--navy);
  border-radius: 3px;
}

.btn-outline-primary:hover {
  background-color: var(--navy);
  border-color: var(--navy);
}

.btn-outline-secondary {
  border-radius: 3px;
}

/* ── Flash alerts ─────────────────────────────────────────────── */
.alert {
  border-radius: 3px;
  font-size: 0.9rem;
}

.alert-success { color: #155724; background-color: #d4edda; border-color: #c3e6cb; }
.alert-danger  { color: #721c24; background-color: #f8d7da; border-color: #f5c6cb; }
.alert-info    { color: #0c5460; background-color: #d1ecf1; border-color: #bee5eb; }
.alert-warning { color: #856404; background-color: #fff3cd; border-color: #ffeeba; }

/* ── Form controls ────────────────────────────────────────────── */
.form-control {
  border-radius: 3px;
  border-color: var(--border);
  font-size: 0.9rem;
}

.form-control:focus {
  border-color: var(--navy-light);
  box-shadow: 0 0 0 0.15rem rgba(30, 58, 95, 0.18);
}

.form-label {
  font-weight: 600;
  font-size: 0.88rem;
  color: #343a40;
}

/* ── List group (example files) ───────────────────────────────── */
.list-group-item {
  border-color: var(--border);
  border-radius: 0 !important;
  font-size: 0.88rem;
  padding: 0.6rem 0.9rem;
}

.list-group-item:first-child {
  border-top-left-radius: 3px !important;
  border-top-right-radius: 3px !important;
}

.list-group-item:last-child {
  border-bottom-left-radius: 3px !important;
  border-bottom-right-radius: 3px !important;
}

/* ── Result stat grid ─────────────────────────────────────────── */
.stat-value {
  font-size: 1.5rem;
  font-weight: 700;
  color: var(--navy);
  line-height: 1.2;
}

.stat-label {
  font-size: 0.78rem;
  color: var(--text-muted);
  text-transform: uppercase;
  letter-spacing: 0.05em;
  margin-top: 0.15rem;
}

/* ── Definition list (method details) ─────────────────────────── */
.dl-academic dt {
  font-weight: 600;
  color: #343a40;
  font-size: 0.88rem;
}

.dl-academic dd {
  color: #495057;
  font-size: 0.88rem;
  margin-bottom: 0.6rem;
}

/* ── Page headings ────────────────────────────────────────────── */
h1.page-title {
  font-size: 1.5rem;
  font-weight: 700;
  color: var(--navy);
  margin-bottom: 0.3rem;
}

.page-subtitle {
  font-size: 0.9rem;
  color: var(--text-muted);
  margin-bottom: 1.5rem;
  max-width: 62ch;
}

/* ── Predicted age display ────────────────────────────────────── */
.predicted-age-display {
  font-size: 2.8rem;
  font-weight: 700;
  color: var(--navy);
  line-height: 1;
}

.predicted-age-unit {
  font-size: 1.1rem;
  font-weight: 400;
  color: var(--text-muted);
  margin-left: 0.25rem;
}

/* ── Footer ───────────────────────────────────────────────────── */
.site-footer {
  background-color: var(--gray-light);
  border-top: 1px solid var(--border);
  padding: 1rem 0;
  margin-top: 3rem;
  font-size: 0.8rem;
  color: var(--text-muted);
  text-align: center;
}

/* ── Intro blurb box ─────────────────────────────────────────── */
.intro-box {
  background-color: var(--gray-light);
  border-left: 3px solid var(--navy);
  padding: 0.75rem 1rem;
  margin-bottom: 1.5rem;
  font-size: 0.88rem;
  color: #495057;
  border-radius: 0 3px 3px 0;
}