/* =========================================================
   istruzioni.css — Stili pagina istruzioni 3DVolleyAnalysis
   Dipende da main.css per le variabili CSS globali (:root)
   ========================================================= */

/* ===== RESET BODY per pagina scrollabile ===== */
/* main.css imposta overflow:hidden su html/body — qui lo sovrascriviamo */
html, body {
  height: auto;
  overflow: auto;
  font-family: var(--font-ui);
}

/* ===== HEADER ===== */
.instr-header {
  position: sticky;
  top: 0;
  z-index: 100;
  background: rgba(10,13,18,0.92);
  backdrop-filter: blur(12px);
  border-bottom: 1px solid var(--border);
  padding: 0 40px;
  height: 56px;
  display: flex;
  align-items: center;
  justify-content: space-between;
}

.instr-brand {
  display: flex;
  align-items: center;
  gap: 12px;
  font-family: var(--font-ui);
  font-size: 20px;
  font-weight: 700;
  letter-spacing: 0.05em;
  color: var(--text-primary);
  text-decoration: none;
}

.instr-brand em {
  color: var(--accent);
  font-style: normal;
}

.instr-back {
  font-family: var(--font-ui);
  font-size: 13px;
  font-weight: 600;
  color: var(--text-secondary);
  text-decoration: none;
  letter-spacing: 0.06em;
  display: flex;
  align-items: center;
  gap: 6px;
  transition: color 0.15s;
}

.instr-back:hover { color: var(--accent); }

/* ===== HERO ===== */
.instr-hero {
  padding: 64px 40px 48px;
  max-width: 900px;
  margin: 0 auto;
}

.instr-hero-tag {
  font-family: var(--font-ui);
  font-size: 11px;
  font-weight: 700;
  letter-spacing: 0.2em;
  text-transform: uppercase;
  color: var(--accent);
  margin-bottom: 16px;
}

.instr-hero h1 {
  font-family: var(--font-ui);
  font-size: 42px;
  font-weight: 700;
  line-height: 1.1;
  letter-spacing: 0.02em;
  color: var(--text-primary);
  margin-bottom: 16px;
}

.instr-hero h1 em {
  color: var(--accent);
  font-style: normal;
}

.instr-hero p {
  font-size: 16px;
  color: var(--text-secondary);
  max-width: 600px;
  line-height: 1.8;
}

/* ===== NAV INDICE ===== */
.instr-toc {
  max-width: 900px;
  margin: 0 auto 48px;
  padding: 0 40px;
  display: flex;
  gap: 12px;
  flex-wrap: wrap;
}

.instr-toc-item {
  font-family: var(--font-ui);
  font-size: 12px;
  font-weight: 600;
  letter-spacing: 0.06em;
  text-transform: uppercase;
  color: var(--text-secondary);
  text-decoration: none;
  padding: 6px 14px;
  border: 1px solid var(--border);
  border-radius: 20px;
  transition: all 0.15s;
}

.instr-toc-item:hover {
  color: var(--accent);
  border-color: var(--border-accent);
  background: var(--accent-glow);
}

/* ===== LAYOUT CONTENUTO ===== */
.instr-content {
  max-width: 900px;
  margin: 0 auto;
  padding: 0 40px 80px;
}

/* ===== SEZIONE ===== */
.instr-section {
  margin-bottom: 64px;
}

.instr-section-header {
  display: flex;
  align-items: center;
  gap: 16px;
  margin-bottom: 32px;
  padding-bottom: 16px;
  border-bottom: 1px solid var(--border);
}

.instr-section-num {
  font-family: var(--font-mono);
  font-size: 11px;
  font-weight: 600;
  color: var(--accent);
  background: var(--accent-glow);
  border: 1px solid var(--border-accent);
  padding: 3px 8px;
  border-radius: var(--radius-sm);
  letter-spacing: 0.1em;
  flex-shrink: 0;
}

.instr-section h2 {
  font-family: var(--font-ui);
  font-size: 26px;
  font-weight: 700;
  letter-spacing: 0.02em;
  color: var(--text-primary);
}

/* ===== STEP LIST ===== */
.instr-step-list {
  display: flex;
  flex-direction: column;
  gap: 16px;
}

.instr-step {
  display: grid;
  grid-template-columns: 40px 1fr;
  gap: 16px;
  align-items: start;
  background: var(--bg-surface);
  border: 1px solid var(--border);
  border-radius: var(--radius-md);
  padding: 20px;
  transition: border-color 0.15s;
}

.instr-step:hover { border-color: var(--border-accent); }

.instr-step-num {
  width: 36px;
  height: 36px;
  border-radius: 50%;
  background: var(--accent-glow);
  border: 1px solid var(--border-accent);
  display: flex;
  align-items: center;
  justify-content: center;
  font-family: var(--font-mono);
  font-size: 14px;
  font-weight: 600;
  color: var(--accent);
  flex-shrink: 0;
}

.instr-step-body h3 {
  font-family: var(--font-ui);
  font-size: 16px;
  font-weight: 700;
  color: var(--text-primary);
  margin-bottom: 6px;
  letter-spacing: 0.02em;
}

.instr-step-body p {
  font-size: 14px;
  color: var(--text-secondary);
  line-height: 1.7;
}

.instr-step-body a {
  color: var(--accent);
  text-decoration: none;
}

.instr-step-body a:hover { text-decoration: underline; }

/* ===== KBD ===== */
.kbd {
  font-family: var(--font-mono);
  font-size: 12px;
  background: var(--bg-hover);
  border: 1px solid var(--border);
  border-radius: 3px;
  padding: 1px 6px;
  color: var(--accent);
}

/* ===== CALLOUT ===== */
.instr-callout {
  border-radius: var(--radius-md);
  padding: 16px 20px;
  margin: 20px 0;
  display: flex;
  gap: 12px;
  align-items: flex-start;
  font-size: 14px;
  line-height: 1.7;
}

.instr-callout-icon {
  font-size: 18px;
  flex-shrink: 0;
  margin-top: 1px;
}

.instr-callout.tip {
  background: var(--green-dim);
  border: 1px solid rgba(0,229,138,0.25);
  color: #a8f0d4;
}

.instr-callout.warning {
  background: rgba(255,214,74,0.06);
  border: 1px solid rgba(255,214,74,0.2);
  color: #f5e49a;
}

.instr-callout.info {
  background: var(--accent-glow);
  border: 1px solid var(--border-accent);
  color: var(--text-secondary);
}

/* ===== TESTO CORPO ===== */
.instr-prose {
  color: var(--text-secondary);
  font-size: 15px;
  line-height: 1.8;
}

.instr-prose p { margin-bottom: 16px; }
.instr-prose p:last-child { margin-bottom: 0; }

.instr-prose strong { color: var(--text-primary); font-weight: 600; }
.instr-prose em     { color: var(--accent); font-style: normal; }
.instr-prose a      { color: var(--accent); text-decoration: none; }
.instr-prose a:hover { text-decoration: underline; }

/* ===== SUBSECTION ===== */
.instr-subsection { margin: 32px 0; }

.instr-subsection h3 {
  font-family: var(--font-ui);
  font-size: 18px;
  font-weight: 700;
  color: var(--text-primary);
  margin-bottom: 12px;
  display: flex;
  align-items: center;
  gap: 10px;
  letter-spacing: 0.02em;
}

.instr-subsection h3 .dot {
  width: 6px;
  height: 6px;
  border-radius: 50%;
  background: var(--accent);
  flex-shrink: 0;
}

/* ===== METODO CALIBRAZIONE ===== */
.instr-method-list {
  display: flex;
  flex-direction: column;
  gap: 14px;
  margin-top: 16px;
}

.instr-method {
  background: var(--bg-surface);
  border: 1px solid var(--border);
  border-radius: var(--radius-md);
  padding: 18px 20px;
  display: grid;
  grid-template-columns: 32px 1fr;
  gap: 14px;
  align-items: start;
  transition: border-color 0.15s;
}

.instr-method:hover { border-color: var(--border-accent); }

.instr-method-icon {
  font-size: 20px;
  text-align: center;
  margin-top: 2px;
}

.instr-method h4 {
  font-family: var(--font-ui);
  font-size: 15px;
  font-weight: 700;
  color: var(--text-primary);
  margin-bottom: 6px;
  letter-spacing: 0.02em;
}

.instr-method p {
  font-size: 13px;
  color: var(--text-secondary);
  line-height: 1.7;
}

/* ===== SCHEMA COORDINATE ===== */
.instr-coord-diagram {
  background: var(--bg-panel);
  border: 1px solid var(--border);
  border-radius: var(--radius-md);
  padding: 28px;
  margin: 20px 0;
  font-family: var(--font-mono);
  font-size: 13px;
  color: var(--text-secondary);
  line-height: 2;
  position: relative;
  overflow: hidden;
}

.instr-coord-diagram::before {
  content: 'SCHEMA CAMPO';
  position: absolute;
  top: 12px;
  right: 16px;
  font-size: 10px;
  letter-spacing: 0.15em;
  color: var(--text-muted);
}

.instr-coord-diagram .c-accent  { color: var(--accent); }
.instr-coord-diagram .c-green   { color: var(--green); }
.instr-coord-diagram .c-yellow  { color: var(--yellow); }
.instr-coord-diagram .c-muted   { color: var(--text-muted); }

/* ===== FORMULA BOX ===== */
.instr-formula {
  background: var(--bg-panel);
  border-left: 3px solid var(--accent);
  border-radius: 0 var(--radius-sm) var(--radius-sm) 0;
  padding: 16px 20px;
  margin: 16px 0;
  font-family: var(--font-mono);
  font-size: 13px;
  color: var(--accent);
  line-height: 1.8;
}

.instr-formula .comment {
  color: var(--text-muted);
  font-size: 12px;
}

/* ===== DIVIDER ===== */
.instr-divider {
  border: none;
  border-top: 1px solid var(--border);
  margin: 48px 0;
}

/* ===== FOOTER ===== */
.instr-footer {
  border-top: 1px solid var(--border);
  padding: 24px 40px;
  text-align: center;
  font-size: 12px;
  color: var(--text-muted);
}

.instr-footer a {
  color: var(--text-secondary);
  text-decoration: none;
}

.instr-footer a:hover { color: var(--accent); }

/* ===== RESPONSIVE ===== */
@media (max-width: 640px) {
  .instr-header   { padding: 0 20px; }
  .instr-hero,
  .instr-toc,
  .instr-content  { padding-left: 20px; padding-right: 20px; }
  .instr-hero h1  { font-size: 28px; }
  .instr-step     { grid-template-columns: 1fr; }
}