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

:root {
  --bg:         #090909;
  --surface:    #111111;
  --surface2:   #181818;
  --border:     #1f1f1f;
  --border2:    #2c2c2c;
  --accent:     #C8FF00;
  --accent-d:   rgba(200,255,0,.10);
  --accent-d2:  rgba(200,255,0,.05);
  --text:       #F0F0F0;
  --text2:      #999;
  --text3:      #4a4a4a;
  --warn:       #FF8C42;
  --warn-d:     rgba(255,140,66,.10);
  --error:      #FF4545;
  --ui:         'Barlow Condensed', sans-serif;
  --mono:       'JetBrains Mono', monospace;
  --max:        640px;
  --r:          4px;
  --r2:         8px;
  --t:          140ms ease;
}

html { scroll-behavior: smooth; }
body {
  background: var(--bg);
  color: var(--text);
  font-family: var(--ui);
  font-size: 18px;
  line-height: 1.5;
  min-height: 100dvh;
  display: flex;
  flex-direction: column;
}

/* ===== ACCESSIBILITY ===== */
.skip-link {
  position: absolute;
  top: -100%; left: 1rem;
  background: var(--accent); color: #000;
  font-family: var(--ui); font-weight: 700; font-size: .9rem;
  letter-spacing: .05em; padding: .5rem 1rem;
  border-radius: var(--r); text-decoration: none; z-index: 200;
}
.skip-link:focus { top: 1rem; }
:focus-visible { outline: 2px solid var(--accent); outline-offset: 3px; }
.sr-only {
  position: absolute; width: 1px; height: 1px;
  overflow: hidden; clip: rect(0,0,0,0); white-space: nowrap;
}

/* ===== HEADER ===== */
header { border-bottom: 1px solid var(--border); padding: 1.1rem 1.5rem; }
.header-inner {
  max-width: var(--max); margin: 0 auto;
  display: flex; align-items: center; gap: 1rem;
  flex-wrap: wrap; justify-content: space-between;
}
.logo-group { display: flex; align-items: baseline; gap: .75rem; }
.logo {
  font-size: clamp(1.4rem, 4vw, 1.8rem); font-weight: 700;
  letter-spacing: -.01em; line-height: 1; color: var(--text);
}
.logo span { color: var(--accent); }
.tagline { font-family: var(--mono); font-size: .7rem; color: var(--text3); }

/* ===== LANG SWITCHER ===== */
.lang-nav { display: flex; gap: .25rem; align-items: center; }
.lang-nav a {
  font-family: var(--mono); font-size: .7rem; font-weight: 700;
  letter-spacing: .08em; padding: .2rem .45rem;
  border: 1px solid var(--border2); border-radius: var(--r);
  color: var(--text3); text-decoration: none;
  transition: color var(--t), border-color var(--t);
}
.lang-nav a:hover { color: var(--text); border-color: var(--text3); }
.lang-nav a[aria-current="page"] {
  color: var(--accent); border-color: var(--accent);
  background: var(--accent-d);
}

/* ===== MAIN ===== */
main { flex: 1; padding: 2rem 1.5rem 3rem; }
.main-inner { max-width: var(--max); margin: 0 auto; }

.page-h1 {
  font-size: clamp(1.2rem, 3.5vw, 1.5rem); font-weight: 700;
  letter-spacing: .02em; margin-bottom: 1.5rem;
}

/* ===== FORM ===== */
.calc-form { display: flex; flex-direction: column; gap: 1.5rem; }

/* Tipo bici */
.tipo-group { display: flex; flex-direction: column; gap: .5rem; }
.field-lbl {
  font-size: .73rem; font-weight: 600; letter-spacing: .12em;
  text-transform: uppercase; color: var(--text2);
}
.radio-grid { display: grid; grid-template-columns: repeat(3, 1fr); gap: .5rem; }
.radio-opt { position: relative; }
.radio-opt input[type="radio"] { position: absolute; opacity: 0; width: 0; height: 0; }
.radio-opt label {
  display: flex; flex-direction: column; align-items: center;
  justify-content: center; gap: .3rem; padding: .8rem .5rem;
  background: var(--surface); border: 1px solid var(--border2);
  border-radius: var(--r2); cursor: pointer;
  transition: border-color var(--t), background var(--t), color var(--t);
  font-size: .88rem; font-weight: 600; color: var(--text2);
  letter-spacing: .03em; text-align: center;
}
.radio-opt label .icon { font-size: 1.35rem; line-height: 1; }
.radio-opt input[type="radio"]:checked + label {
  background: var(--accent-d); border-color: var(--accent); color: var(--accent);
}
.radio-opt label:hover { border-color: var(--text3); color: var(--text); }
.radio-opt input[type="radio"]:focus-visible + label {
  outline: 2px solid var(--accent); outline-offset: 2px;
}

/* Field pair */
.field-pair { display: grid; grid-template-columns: 1fr 1fr; gap: 1rem; }
.field { display: flex; flex-direction: column; gap: .35rem; }
.field > label {
  font-size: .73rem; font-weight: 600; letter-spacing: .12em;
  text-transform: uppercase; color: var(--text2);
}
.field > label .opt {
  font-weight: 400; font-size: .68rem; letter-spacing: 0;
  text-transform: none; color: var(--text3);
}
.input-wrap { position: relative; }
.input-wrap input[type="number"] {
  width: 100%; background: var(--surface); border: 1px solid var(--border2);
  border-radius: var(--r); color: var(--text); font-family: var(--mono);
  font-size: 1.35rem; font-weight: 700; padding: .6rem 2.5rem .6rem .75rem;
  appearance: textfield; -moz-appearance: textfield;
  transition: border-color var(--t), background var(--t);
}
.input-wrap input[type="number"]::-webkit-inner-spin-button,
.input-wrap input[type="number"]::-webkit-outer-spin-button { display: none; }
.input-wrap input[type="number"]:hover { border-color: var(--text3); }
.input-wrap input[type="number"]:focus {
  border-color: var(--accent); background: var(--surface2); outline: none;
}
.input-wrap input[type="number"].err { border-color: var(--error); }
.input-unit {
  position: absolute; right: .65rem; top: 50%; transform: translateY(-50%);
  font-family: var(--mono); font-size: .7rem; color: var(--text3);
  pointer-events: none; user-select: none;
}
.field-hint { font-family: var(--mono); font-size: .68rem; color: var(--text3); line-height: 1.3; }
.field-error { font-family: var(--mono); font-size: .72rem; color: var(--error); min-height: 1em; }

/* Submit */
.btn-calc {
  background: var(--accent); color: #000; border: none; border-radius: var(--r);
  font-family: var(--ui); font-size: 1.1rem; font-weight: 700;
  letter-spacing: .08em; text-transform: uppercase;
  padding: .9rem; cursor: pointer; width: 100%;
  transition: filter var(--t), transform 80ms ease;
}
.btn-calc:hover { filter: brightness(1.1); }
.btn-calc:active { transform: scale(.98); }

/* ===== DIVIDER ===== */
.divider { border: none; border-top: 1px solid var(--border); margin: 2rem 0; }

/* ===== RESULTS ===== */
#results { display: none; }
#results.show { display: block; }

@keyframes fadeUp {
  from { opacity: 0; transform: translateY(6px); }
  to   { opacity: 1; transform: translateY(0); }
}
#results.show { animation: fadeUp 200ms ease both; }

.res-topbar {
  display: flex; align-items: center;
  justify-content: space-between; margin-bottom: .75rem;
}
.res-section-lbl {
  font-size: .7rem; font-weight: 600; letter-spacing: .14em;
  text-transform: uppercase; color: var(--text3);
}
.res-tipo-pill {
  font-size: .68rem; font-weight: 700; letter-spacing: .1em;
  text-transform: uppercase; color: var(--accent);
  background: var(--accent-d); border: 1px solid var(--accent);
  border-radius: 2px; padding: .2rem .55rem;
}

.res-card {
  background: var(--surface); border: 1px solid var(--border2);
  border-radius: var(--r2); overflow: hidden; margin-bottom: .75rem;
}
.res-main {
  display: grid; grid-template-columns: 1fr 1fr;
  border-bottom: 1px solid var(--border);
}
.res-cell { padding: 1.25rem 1.25rem 1rem; }
.res-cell + .res-cell { border-left: 1px solid var(--border); }
.res-cell-lbl {
  font-size: .68rem; font-weight: 600; letter-spacing: .12em;
  text-transform: uppercase; color: var(--text3); margin-bottom: .35rem;
}
.res-cell-val {
  font-family: var(--mono); font-weight: 700;
  font-size: clamp(2.4rem, 9vw, 3.4rem); line-height: 1; color: var(--accent);
}
.res-cell-val.telaio { font-size: clamp(1.7rem, 6vw, 2.3rem); }
.res-cell-sub {
  font-family: var(--mono); font-size: .7rem; color: var(--text3);
  margin-top: .35rem; line-height: 1.5; white-space: pre-line;
}

.res-details { display: grid; grid-template-columns: repeat(3, 1fr); }
.res-det { padding: .8rem 1rem; }
.res-det + .res-det { border-left: 1px solid var(--border); }
.res-det-lbl {
  font-size: .65rem; font-weight: 600; letter-spacing: .1em;
  text-transform: uppercase; color: var(--text3); margin-bottom: .2rem;
}
.res-det-val { font-family: var(--mono); font-size: .88rem; font-weight: 700; color: var(--text2); }

.res-warn {
  display: none; gap: .65rem; padding: .8rem 1rem;
  background: var(--warn-d); border: 1px solid var(--warn); border-radius: var(--r);
  font-size: .82rem; color: var(--warn); line-height: 1.45; margin-bottom: .75rem;
}
.res-warn.show { display: flex; }
.res-warn-icon { flex-shrink: 0; }

.res-formula {
  font-family: var(--mono); font-size: .7rem; color: var(--text3);
  padding: .7rem 1rem; background: var(--surface);
  border: 1px solid var(--border); border-radius: var(--r); line-height: 1.8;
}
.res-formula b { color: var(--text2); font-weight: 700; }
.res-formula em { color: var(--accent); font-style: normal; font-weight: 700; }

/* ===== TABLE SECTION ===== */
.table-section { margin-top: 2.5rem; }
.section-h2 {
  font-size: 1rem; font-weight: 700; letter-spacing: .04em;
  color: var(--text2); margin-bottom: 1rem;
  padding-bottom: .6rem; border-bottom: 1px solid var(--border);
}

.tabs {
  display: flex; border: 1px solid var(--border2);
  border-radius: var(--r); overflow: hidden; margin-bottom: 1rem;
}
.tab-btn {
  flex: 1; background: transparent; border: none;
  border-right: 1px solid var(--border2); padding: .55rem .5rem;
  font-family: var(--ui); font-size: .88rem; font-weight: 600;
  letter-spacing: .04em; color: var(--text2); cursor: pointer;
  transition: background var(--t), color var(--t);
}
.tab-btn:last-child { border-right: none; }
.tab-btn:hover { background: var(--surface2); color: var(--text); }
.tab-btn[aria-selected="true"] { background: var(--accent-d); color: var(--accent); }

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

.sz-table { width: 100%; border-collapse: collapse; font-size: .83rem; }
.sz-table th {
  font-size: .65rem; font-weight: 600; letter-spacing: .1em;
  text-transform: uppercase; color: var(--text3);
  padding: .5rem .75rem; text-align: left;
  border-bottom: 1px solid var(--border); white-space: nowrap;
}
.sz-table td {
  padding: .55rem .75rem; border-bottom: 1px solid var(--border);
  font-family: var(--mono); font-size: .8rem; color: var(--text2); white-space: nowrap;
}
.sz-table tr:last-child td { border-bottom: none; }
.sz-table tbody tr:hover td { background: var(--surface); }
.sz-table td.t-tag {
  font-family: var(--ui); font-size: 1.05rem;
  font-weight: 700; letter-spacing: .04em; color: var(--text);
}
.sz-table tr.hl td { background: var(--accent-d2); color: var(--text); }
.sz-table tr.hl td.t-tag { color: var(--accent); }
.sz-table tr.hl:hover td { background: var(--accent-d); }

/* ===== FOOTER ===== */
footer { border-top: 1px solid var(--border); padding: 1.25rem 1.5rem; }
.footer-inner {
  max-width: var(--max); margin: 0 auto;
  display: flex; justify-content: space-between;
  align-items: flex-start; gap: 1.5rem; flex-wrap: wrap;
}
.footer-note {
  font-family: var(--mono); font-size: .7rem;
  color: var(--text3); line-height: 1.6; max-width: 460px;
}
.footer-cr { font-family: var(--mono); font-size: .7rem; color: var(--text3); white-space: nowrap; }

/* ===== DESKTOP ===== */
@media (min-width: 900px) {
  :root { --max: 760px; }

  body { font-size: 20px; }

  main { padding: 3rem 2rem 5rem; }

  /* Headings */
  .page-h1 { font-size: 1.9rem; margin-bottom: 2rem; }
  .section-h2 { font-size: 1.1rem; }

  /* Form */
  .calc-form { gap: 2rem; }
  .radio-opt label { padding: 1rem .75rem; font-size: 1rem; }
  .radio-opt label .icon { font-size: 1.6rem; }
  .field > label { font-size: .85rem; }
  .field-hint { font-size: .78rem; }
  .field-error { font-size: .82rem; }
  .input-wrap input[type="number"] { font-size: 1.5rem; padding: .7rem 2.8rem .7rem .85rem; }
  .input-unit { font-size: .8rem; }
  .btn-calc { font-size: 1.2rem; padding: 1rem; }

  /* Results */
  .res-cell-val { font-size: 3.6rem; }
  .res-cell-val.telaio { font-size: 2.5rem; }
  .res-cell { padding: 1.5rem 1.5rem 1.1rem; }
  .res-det { padding: 1rem 1.25rem; }
  .res-det-lbl { font-size: .75rem; }
  .res-det-val { font-size: 1rem; }
  .res-formula { font-size: .82rem; padding: .9rem 1.25rem; }
  .res-warn { font-size: .9rem; }

  /* Table */
  .sz-table th { font-size: .75rem; padding: .65rem 1rem; }
  .sz-table td { font-size: .9rem; padding: .7rem 1rem; }
  .sz-table td.t-tag { font-size: 1.15rem; }

  /* Tabs */
  .tab-btn { font-size: 1rem; padding: .65rem .75rem; }
}

/* ===== MOTION / RESPONSIVE ===== */
@media (prefers-reduced-motion: reduce) {
  *, *::before, *::after { animation-duration: .01ms !important; transition-duration: .01ms !important; }
}
@media (max-width: 460px) {
  .field-pair { grid-template-columns: 1fr; }
  .res-details { grid-template-columns: 1fr 1fr; }
  .res-det:nth-child(3) { border-left: none; border-top: 1px solid var(--border); grid-column: 1 / -1; }
  .footer-inner { flex-direction: column; }
  .lang-nav { flex-wrap: wrap; }
}


/* ===== SEO / CONTENT BLOCKS ===== */
.info-grid {
  display: grid;
  grid-template-columns: 1fr;
  gap: .8rem;
  margin: 2rem 0 0;
}
.info-card, .faq-item, .note-box, .ad-slot {
  background: var(--surface);
  border: 1px solid var(--border2);
  border-radius: var(--r2);
  padding: 1rem;
}
.info-card h2, .info-card h3, .faq-item h3, .note-box h2 {
  font-size: 1rem;
  color: var(--text);
  margin-bottom: .45rem;
  letter-spacing: .04em;
}
.info-card p, .faq-item p, .note-box p, .note-box li {
  color: var(--text2);
  font-size: .9rem;
  line-height: 1.55;
}
.info-card ul, .note-box ul {
  padding-left: 1.1rem;
  display: grid;
  gap: .35rem;
}
.faq-section { margin-top: 2.5rem; display: grid; gap: .75rem; }
.ad-slot {
  margin: 2rem 0 0;
  min-height: 92px;
  display: grid;
  place-items: center;
  border-style: dashed;
  color: var(--text3);
  font-family: var(--mono);
  font-size: .7rem;
  text-align: center;
}
.footer-links {
  display: flex;
  flex-wrap: wrap;
  gap: .65rem;
  font-family: var(--mono);
  font-size: .7rem;
}
.footer-links a { color: var(--text3); text-decoration: none; }
.footer-links a:hover { color: var(--accent); }

@media (min-width: 900px) {
  .info-grid { grid-template-columns: repeat(2, 1fr); gap: 1rem; }
  .info-card, .faq-item, .note-box, .ad-slot { padding: 1.15rem; }
  .info-card p, .faq-item p, .note-box p, .note-box li { font-size: 1rem; }
}


/* ===== V3 DESKTOP REFINEMENT =====
   Layout più pieno su schermi larghi: form a sinistra, guida a destra.
   Mobile invariato. Perché sì, anche il vuoto cosmico ha dei limiti.
*/
body {
  background:
    radial-gradient(circle at 50% 0%, rgba(200,255,0,.055), transparent 34rem),
    linear-gradient(180deg, #090909 0%, #060606 100%);
}

header {
  position: sticky;
  top: 0;
  z-index: 50;
  background: rgba(9,9,9,.86);
  backdrop-filter: blur(12px);
}

@media (min-width: 900px) {
  :root { --max: 1120px; }

  header { padding: 1.25rem 2rem; }

  .header-inner,
  .footer-inner {
    max-width: var(--max);
  }

  main {
    padding: 4rem 2rem 5rem;
  }

  .main-inner {
    max-width: var(--max);
    display: grid;
    grid-template-columns: minmax(0, 680px) minmax(300px, 1fr);
    column-gap: 2rem;
    row-gap: 1.5rem;
    align-items: start;
  }

  .page-h1 {
    grid-column: 1 / -1;
    max-width: 760px;
    margin-bottom: .25rem;
    font-size: clamp(2rem, 3vw, 2.65rem);
    line-height: 1;
  }

  .calc-form {
    grid-column: 1;
    background: linear-gradient(180deg, rgba(255,255,255,.025), rgba(255,255,255,.01));
    border: 1px solid var(--border2);
    border-radius: 14px;
    padding: 1.35rem;
    box-shadow: 0 24px 80px rgba(0,0,0,.28);
  }

  .info-grid {
    grid-column: 2;
    grid-row: 2 / span 2;
    margin: 0;
    grid-template-columns: 1fr;
    gap: .9rem;
    position: sticky;
    top: 6.2rem;
  }

  .info-card {
    background: rgba(17,17,17,.78);
  }

  .ad-slot {
    grid-column: 2;
    margin: 0;
    min-height: 120px;
  }

  .divider {
    grid-column: 1 / -1;
    margin: .5rem 0 0;
  }

  #results {
    grid-column: 1;
  }

  #results.show {
    margin-top: 0;
  }

  .table-section,
  .faq-section,
  .note-box {
    grid-column: 1 / -1;
  }

  .table-section {
    margin-top: 1rem;
  }

  .tabs {
    max-width: 680px;
  }

  .tab-panel {
    background: rgba(17,17,17,.48);
    border: 1px solid var(--border);
    border-radius: var(--r2);
  }

  .tab-panel .sz-table {
    overflow: hidden;
  }

  .faq-section {
    grid-template-columns: repeat(2, minmax(0, 1fr));
  }

  .section-h2 {
    font-size: 1.25rem;
  }
}

@media (min-width: 1280px) {
  :root { --max: 1240px; }

  .main-inner {
    grid-template-columns: minmax(0, 720px) minmax(360px, 1fr);
    column-gap: 2.5rem;
  }

  .calc-form {
    padding: 1.5rem;
  }
}

@media (max-width: 899px) {
  header {
    position: static;
    background: var(--bg);
    backdrop-filter: none;
  }
}


/* ===== V4 FIX DESKTOP LAYOUT =====
   Correzione: in v3 la sidebar sticky poteva sovrapporsi a tabella e FAQ.
   Qui il desktop resta largo, ma ogni blocco torna nel suo recinto.
*/
@media (min-width: 900px) {
  .main-inner {
    display: grid;
    grid-template-columns: minmax(0, 680px) minmax(320px, 1fr);
    column-gap: 2rem;
    row-gap: 1.5rem;
    align-items: start;
  }

  .page-h1 {
    grid-column: 1 / -1;
    grid-row: auto;
  }

  .calc-form {
    grid-column: 1;
    grid-row: auto;
  }

  .info-grid {
    grid-column: 2;
    grid-row: auto;
    position: static;
    top: auto;
    align-self: start;
  }

  .ad-slot {
    grid-column: 2;
    grid-row: auto;
    margin: 0;
  }

  .divider,
  #results,
  .table-section,
  .faq-section,
  .note-box {
    grid-column: 1 / -1;
    grid-row: auto;
    position: relative;
    z-index: 1;
  }

  .table-section {
    margin-top: 1.25rem;
  }

  .tabs {
    max-width: 720px;
  }

  .tab-panel {
    width: 100%;
  }

  .faq-section {
    display: grid;
    grid-template-columns: repeat(3, minmax(0, 1fr));
    gap: .9rem;
  }

  .faq-section > .section-h2 {
    grid-column: 1 / -1;
  }
}

@media (min-width: 1280px) {
  .main-inner {
    grid-template-columns: minmax(0, 760px) minmax(360px, 1fr);
    column-gap: 2.5rem;
  }
}

@media (max-width: 899px) {
  .faq-section {
    display: grid;
    grid-template-columns: 1fr;
  }
}


/* ===== V5 TECHNICAL RESULT IMPROVEMENTS ===== */
.fit-extra {
  display: grid;
  grid-template-columns: 1fr 1fr;
  gap: .75rem;
  margin-top: .75rem;
}
.fit-chip,
.fit-advice {
  background: var(--surface);
  border: 1px solid var(--border);
  border-radius: var(--r);
  padding: .8rem 1rem;
}
.fit-k,
.fit-advice strong {
  display: block;
  font-size: .68rem;
  font-weight: 700;
  letter-spacing: .12em;
  text-transform: uppercase;
  color: var(--text3);
  margin-bottom: .25rem;
}
.fit-v {
  font-family: var(--mono);
  font-size: .95rem;
  font-weight: 700;
  color: var(--text2);
}
.confidence-high { color: var(--accent); }
.confidence-medium { color: var(--warn); }
.confidence-low { color: var(--error); }
.fit-advice {
  grid-column: 1 / -1;
  line-height: 1.55;
}
.fit-advice p {
  color: var(--text2);
  font-size: .95rem;
}
.sz-table tr.hl-soft td {
  background: rgba(255,140,66,.055);
  box-shadow: inset 3px 0 0 rgba(255,140,66,.75);
}
input[aria-invalid="true"] {
  border-color: var(--error) !important;
}
.noscript-box {
  max-width: var(--max);
  margin: 1rem auto;
  padding: 1rem;
  background: var(--warn-d);
  border: 1px solid var(--warn);
  border-radius: var(--r);
  color: var(--warn);
}

@media (min-width: 900px) {
  .fit-extra {
    grid-template-columns: repeat(2, minmax(0, 1fr));
  }
}

@media (max-width: 560px) {
  .fit-extra { grid-template-columns: 1fr; }
  .fit-advice { grid-column: auto; }
}


/* ===== V7 AD PLACEHOLDERS - inactive until AdSense/CMP setup ===== */
.ad-slot {
  grid-column: 1 / -1;
  min-height: 90px;
  border: 1px dashed var(--border);
  border-radius: var(--r);
  background: color-mix(in srgb, var(--surface) 78%, transparent);
  color: var(--text3);
  display: grid;
  place-items: center;
  text-align: center;
  font-size: .78rem;
  letter-spacing: .08em;
  text-transform: uppercase;
  padding: 1rem;
}
.ad-slot-top,
.ad-slot-bottom {
  width: min(var(--max), calc(100% - 2rem));
  margin: 1rem auto;
}
.ad-slot-mid { margin: 1rem 0; }
@media (max-width: 640px) {
  .ad-slot-top { display: none; }
}
@media print {
  .ad-slot { display: none !important; }
}