/* Riferimento visivo: foglio da disegno tecnico con griglia di costruzione e cartiglio. */
:root {
  --ink: #1d3557;
  --ink-strong: #14253d;
  --graphite: #3a4048;
  --rule: #c9d3de;
  --trace: #e8eef5;
  --paper: #f7f9fb;
  --redline: #b3261e;

  --bs-body-font-family: "Barlow", system-ui, -apple-system, "Segoe UI", sans-serif;
  --bs-body-color: var(--graphite);
  --bs-link-color-rgb: 29, 53, 87;
  --bs-link-hover-color-rgb: 20, 37, 61;
  --bs-danger-rgb: 179, 38, 30;
  --bs-border-color: var(--rule);
}

body {
  background-color: var(--paper);
  /* Griglia 5 mm / 25 mm come su carta millimetrata; puramente decorativa. */
  background-image:
    linear-gradient(var(--trace) 1px, transparent 1px),
    linear-gradient(90deg, var(--trace) 1px, transparent 1px);
  background-size: 24px 24px;
  min-height: 100vh;
}

h1, h2, .sheet-title, .navbar-brand, .kpi-v {
  font-family: "Barlow Condensed", "Arial Narrow", sans-serif;
  letter-spacing: .01em;
}

.app-nav { background: var(--ink); }
.app-nav .navbar-brand, .app-nav .nav-link, .app-nav .navbar-text { color: #fff; }
.app-nav .nav-link { opacity: .75; }
.app-nav .nav-link.active, .app-nav .nav-link:hover { opacity: 1; }
.app-nav .navbar-toggler { border-color: rgba(255, 255, 255, .4); filter: invert(1); }
.brand-sub { font-weight: 500; opacity: .6; margin-left: .35rem; }

.btn-ink {
  --bs-btn-color: #fff;
  --bs-btn-bg: var(--ink);
  --bs-btn-border-color: var(--ink);
  --bs-btn-hover-color: #fff;
  --bs-btn-hover-bg: var(--ink-strong);
  --bs-btn-hover-border-color: var(--ink-strong);
  --bs-btn-disabled-bg: var(--ink);
  --bs-btn-disabled-border-color: var(--ink);
}

:focus-visible { outline: 2px solid var(--ink); outline-offset: 2px; }
.form-control:focus, .form-check-input:focus { border-color: var(--ink); box-shadow: 0 0 0 .2rem rgba(29, 53, 87, .2); }
.form-check-input:checked { background-color: var(--ink); border-color: var(--ink); }

/* Cartiglio: unico elemento con carattere, il resto dell'interfaccia resta neutro. */
.title-block {
  max-width: 440px;
  margin-top: 8vh;
  background: #fff;
  border: 2px solid var(--ink);
}
.tb-head { display: flex; border-bottom: 1px solid var(--ink); }
.tb-cell { padding: .5rem .75rem; border-left: 1px solid var(--ink); }
.tb-cell:first-child { border-left: 0; }
.tb-grow { flex: 1; }
.tb-label { display: block; font-size: .72rem; color: #6b7480; }
.tb-title { font-size: 1.75rem; font-weight: 600; margin: 0; color: var(--ink); line-height: 1.1; }
.tb-value { font-family: "Barlow Condensed", sans-serif; font-size: 1.25rem; color: var(--ink); }
.tb-sub { padding: .45rem .75rem; border-bottom: 1px solid var(--rule); font-size: .92rem; }
.tb-body { padding: 1.25rem .75rem 1rem; }

.sheet {
  background: #fff;
  border: 1px solid var(--rule);
  border-radius: 2px;
  padding: 1.25rem;
}
.sheet-title { font-size: 1.35rem; font-weight: 600; color: var(--ink); margin-bottom: 1rem; }

.sheet-meta { display: grid; grid-template-columns: max-content 1fr; gap: .25rem 1rem; margin-bottom: 1.25rem; }
.sheet-meta dt { font-weight: 500; color: #6b7480; }
.sheet-meta dd { margin: 0; }

.drop-zone {
  display: flex;
  flex-direction: column;
  align-items: center;
  gap: .25rem;
  padding: 1.75rem 1rem;
  border: 1.5px dashed var(--ink);
  background: var(--paper);
  text-align: center;
  cursor: pointer;
  transition: background-color .15s;
}
.drop-zone .bi { font-size: 2rem; color: var(--ink); }
.drop-zone.over { background: var(--trace); }
.drop-zone:focus-within { outline: 2px solid var(--ink); outline-offset: 2px; }
.dz-main { font-weight: 500; }
.dz-hint { font-size: .85rem; color: #6b7480; }

.course-tabs .nav-link { color: var(--ink); border-radius: 2px; }
.course-tabs .nav-link.active { background: var(--ink); }

.kpi { background: #fff; border: 1px solid var(--rule); border-left: 4px solid var(--ink); padding: .9rem 1rem; }
.kpi-v { display: block; font-size: 2rem; font-weight: 600; color: var(--ink); line-height: 1; }
.kpi-l { font-size: .9rem; color: #6b7480; }

.progress { height: .5rem; border-radius: 0; background: var(--trace); }
.progress-bar { background: var(--ink); }

.table > thead th { font-weight: 500; color: #6b7480; border-bottom-color: var(--ink); }

@media (prefers-reduced-motion: reduce) {
  * { transition: none !important; }
}