/* =====================================================================
   MasterApps · Design System  "Quaderno"
   Notebook / bullet-journal aesthetic. Shared across all pages.
   ===================================================================== */
@import url('https://fonts.googleapis.com/css2?family=Bricolage+Grotesque:opsz,wght@12..96,600;12..96,700;12..96,800&display=swap');

:root{
  /* ink + paper */
  --ink:        #1d2438;
  --ink-soft:   #4a5470;
  --ink-faint:  #7b8398;
  --paper:      #FBFAF4;
  --paper-card: #ffffff;
  --grid-line:  rgba(96,124,170,.15);
  --margin-red: #E0512E;

  /* brand accents */
  --accent:     #E0512E;   /* master red-orange (math icon) */
  --accent-2:   #1F8A7A;   /* teal */
  --accent-3:   #2E74C0;   /* blue */
  --hl:         #FFE08A;   /* highlighter yellow */

  /* shadows */
  --shadow-hard: 4px 4px 0 rgba(29,36,56,.13);
  --radius: 16px;

  --font-display: 'Bricolage Grotesque', 'Lexend', system-ui, sans-serif;
  --font-head: 'Lexend', system-ui, sans-serif;
  --font-body: 'Nunito', system-ui, sans-serif;
  --font-hand: 'Caveat', cursive;
  --maxw: 1180px;
}

*{ box-sizing:border-box; }
html{ scroll-behavior:smooth; }
body{
  margin:0;
  font-family:var(--font-body);
  color:var(--ink);
  background-color:var(--paper);
  background-image:
    linear-gradient(var(--grid-line) 1px, transparent 1px),
    linear-gradient(90deg, var(--grid-line) 1px, transparent 1px);
  background-size:26px 26px;
  -webkit-font-smoothing:antialiased;
  text-rendering:optimizeLegibility;
}
img{ max-width:100%; display:block; }
a{ color:inherit; }

.wrap{ max-width:var(--maxw); margin:0 auto; padding:0 28px; }
.section{ padding:72px 0; }

/* ---------- handwriting / highlighter helpers ---------- */
.hand{ font-family:var(--font-hand); font-weight:600; }
.hl{ position:relative; white-space:nowrap; }
.hl>span{ position:relative; z-index:1; }
.hl::after{ content:''; position:absolute; left:-5px; right:-5px; bottom:5px;
  height:42%; background:var(--hl); z-index:0; transform:rotate(-1.1deg); border-radius:3px; }
.marker{ background:var(--hl); padding:0 .18em; box-decoration-break:clone; -webkit-box-decoration-break:clone; }

/* ---------- buttons ---------- */
.btn{ display:inline-flex; align-items:center; gap:9px; cursor:pointer;
  font-family:var(--font-head); font-weight:600; font-size:15px; line-height:1;
  padding:13px 20px; border-radius:13px; text-decoration:none; border:2px solid var(--ink);
  background:var(--ink); color:#fff; transition:transform .12s ease, box-shadow .12s ease; }
.btn:hover{ transform:translate(-1px,-1px); box-shadow:3px 3px 0 var(--ink); }
.btn.ghost{ background:#fff; color:var(--ink); }
.btn.ghost:hover{ box-shadow:3px 3px 0 var(--ink); }
.btn.accent{ background:var(--accent); border-color:var(--accent); }
.btn.accent:hover{ box-shadow:3px 3px 0 #93311a; }

/* ---------- store buttons ---------- */
.stores{ display:flex; gap:12px; flex-wrap:wrap; }
.storebtn{ display:inline-flex; align-items:center; gap:10px; text-decoration:none;
  padding:11px 17px; border-radius:13px; background:var(--ink); color:#fff;
  box-shadow:0 3px 0 rgba(0,0,0,.18); transition:transform .12s ease; }
.storebtn:hover{ transform:translateY(-2px); }
.storebtn svg{ width:22px; height:22px; flex:none; }
.storebtn .t{ font-family:var(--font-head); line-height:1.1; }
.storebtn .t small{ display:block; font-size:9.5px; opacity:.72; letter-spacing:.4px; margin-bottom:3px; text-transform:uppercase; }
.storebtn .t b{ font-size:16px; font-weight:600; }
.storebtn.ghost{ background:#fff; color:var(--ink); border:1.5px solid var(--ink); box-shadow:3px 3px 0 var(--ink); }

/* ---------- nav ---------- */
.nav{ position:sticky; top:0; z-index:50; background:rgba(251,250,244,.86);
  backdrop-filter:blur(8px); border-bottom:1.5px solid var(--ink); }
.nav-in{ max-width:var(--maxw); margin:0 auto; padding:14px 28px;
  display:flex; align-items:center; justify-content:space-between; gap:20px; }
.brand{ display:flex; align-items:center; gap:11px; text-decoration:none; color:var(--ink); }
.brand b{ font-family:var(--font-head); font-weight:700; font-size:20px; letter-spacing:-.01em; }
.nav-links{ display:flex; align-items:center; gap:26px; }
.nav-links a{ font-family:var(--font-head); font-weight:500; font-size:14.5px; color:var(--ink-soft); text-decoration:none; }
.nav-links a:hover{ color:var(--accent); }

/* language selector */
.lang{ position:relative; font-family:var(--font-head); }
.lang-btn{ display:inline-flex; align-items:center; gap:6px; font-size:14px; font-weight:600;
  color:var(--ink); background:#fff; border:1.5px solid var(--ink); border-radius:10px;
  padding:7px 11px; cursor:pointer; }
.lang-menu{ position:absolute; right:0; top:calc(100% + 8px); background:#fff;
  border:1.5px solid var(--ink); border-radius:12px; box-shadow:var(--shadow-hard);
  padding:7px; display:none; grid-template-columns:1fr 1fr; gap:2px; width:230px; max-height:300px; overflow:auto; z-index:60; }
.lang-menu.open{ display:grid; }
.lang-menu button, .lang-menu a{ text-align:left; background:none; border:none; cursor:pointer; text-decoration:none; display:block;
  font-family:var(--font-head); font-size:13.5px; color:var(--ink-soft); padding:8px 9px; border-radius:8px; }
.lang-menu button:hover, .lang-menu a:hover{ background:var(--paper); color:var(--ink); }
.lang-menu button[aria-current="true"], .lang-menu a[aria-current="true"]{ color:var(--accent); font-weight:700; }

/* ---------- app card ---------- */
.app-grid{ display:grid; grid-template-columns:repeat(4,1fr); gap:18px; }
.app-card{ position:relative; display:flex; flex-direction:column;
  background:var(--paper-card); border:2px solid var(--c,#1d2438); border-radius:var(--radius);
  padding:18px; color:var(--ink);
  box-shadow:4px 4px 0 color-mix(in srgb, var(--c,#1d2438) 28%, transparent);
  transition:transform .14s ease, box-shadow .14s ease; }
.app-card:hover{ transform:translate(-2px,-2px);
  box-shadow:7px 7px 0 color-mix(in srgb, var(--c,#1d2438) 40%, transparent); }
.app-ic{ width:60px; height:60px; border-radius:15px; overflow:hidden; margin-bottom:13px;
  box-shadow:0 3px 7px rgba(0,0,0,.16); }
.app-ic img{ width:100%; height:100%; object-fit:cover; }
.app-name{ font-family:var(--font-head); font-weight:700; font-size:17px; letter-spacing:-.01em; text-decoration:none; color:var(--ink); }
.app-name:hover{ color:var(--c,var(--accent)); }
.app-tag{ font-size:13px; color:var(--ink-faint); margin-top:4px; line-height:1.35; flex:1; }
.app-plat{ display:flex; gap:5px; align-items:center; margin-top:10px; }
.app-plat svg{ width:14px; height:14px; opacity:.45; }
.app-foot{ display:flex; align-items:center; gap:8px;
  border-top:1px dashed color-mix(in srgb, var(--c,#1d2438) 35%, #d4d8e2);
  margin-top:12px; padding-top:12px; }
.cardbtn{ flex:1; display:inline-flex; align-items:center; justify-content:center; gap:6px;
  font-family:var(--font-head); font-weight:600; font-size:13px; line-height:1; cursor:pointer;
  padding:9px 10px; border-radius:10px; text-decoration:none; border:1.5px solid var(--c,#1d2438);
  transition:transform .12s ease, box-shadow .12s ease, background .12s ease; }
.cardbtn.get{ background:var(--c,#1d2438); color:#fff; }
.cardbtn.get:hover{ transform:translateY(-1px); box-shadow:0 3px 0 color-mix(in srgb,var(--c,#1d2438) 55%,#000); }
.cardbtn.det{ background:#fff; color:var(--c,#1d2438); }
.cardbtn.det:hover{ transform:translateY(-1px); box-shadow:2px 2px 0 var(--c,#1d2438); }

/* ---------- pills / filters ---------- */
.pills{ display:flex; gap:9px; flex-wrap:wrap; }
.pill{ font-family:var(--font-head); font-size:13.5px; font-weight:500; cursor:pointer;
  background:#fff; color:var(--ink-soft); border:1.5px solid var(--ink); border-radius:30px;
  padding:7px 15px; transition:all .12s ease; }
.pill:hover{ color:var(--ink); }
.pill[aria-pressed="true"]{ background:var(--ink); color:#fff; }

/* ---------- stat ---------- */
.stats{ display:flex; gap:38px; flex-wrap:wrap; }
.stat .n{ font-family:var(--font-head); font-weight:800; font-size:34px; line-height:1; }
.stat .l{ font-size:13px; color:var(--ink-faint); margin-top:5px; }

/* ---------- sticky note (reviews) ---------- */
.note{ position:relative; background:#fff; border-radius:4px; padding:22px 20px 18px;
  box-shadow:2px 5px 14px rgba(0,0,0,.1); }
.washi{ position:absolute; width:78px; height:22px; left:50%; margin-left:-39px; top:-9px;
  background:repeating-linear-gradient(45deg, var(--w,#7FD1C8) 0 7px, color-mix(in srgb,var(--w,#7FD1C8) 65%,#fff) 7px 14px);
  box-shadow:0 2px 4px rgba(0,0,0,.08); transform:rotate(-2deg); }

/* ---------- footer ---------- */
.foot{ border-top:2px solid var(--ink); background:#fff; }
.foot-in{ max-width:var(--maxw); margin:0 auto; padding:54px 28px 34px;
  display:grid; grid-template-columns:1.4fr 1fr 1fr 1fr; gap:30px; }
.foot h4{ font-family:var(--font-head); font-size:13px; text-transform:uppercase; letter-spacing:.06em; color:var(--ink-faint); margin:0 0 14px; }
.foot a{ display:block; color:var(--ink-soft); text-decoration:none; font-size:14.5px; margin-bottom:9px; }
.foot a:hover{ color:var(--accent); }
.foot-bottom{ border-top:1px dashed #cfd4df; max-width:var(--maxw); margin:0 auto; padding:18px 28px 30px;
  display:flex; justify-content:space-between; gap:16px; flex-wrap:wrap; font-size:13px; color:var(--ink-faint); }

/* ---------- section heading ---------- */
.eyebrow{ font-family:var(--font-hand); font-size:25px; color:var(--accent); margin:0 0 6px; transform:rotate(-1.5deg); display:inline-block; }
.h2{ font-family:var(--font-display); font-weight:700; font-size:clamp(28px,3.4vw,40px); letter-spacing:-.015em; margin:0 0 14px; line-height:1.08; }
.lead{ font-size:18px; line-height:1.55; color:var(--ink-soft); max-width:620px; }

/* ---------- responsive ---------- */
@media (max-width:1000px){
  .app-grid{ grid-template-columns:repeat(3,1fr); }
  .foot-in{ grid-template-columns:1fr 1fr; }
}
@media (max-width:720px){
  .app-grid{ grid-template-columns:repeat(2,1fr); gap:13px; }
  .nav-links{ display:none; }
  .section{ padding:52px 0; }
  .stats{ gap:24px; }
  .foot-in{ grid-template-columns:1fr 1fr; }
}
@media (max-width:430px){
  .app-grid{ grid-template-columns:1fr 1fr; }
}

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

/* =====================================================================
   App detail page  (physics.html, chimica.html, ...)
   ===================================================================== */
.crumb{ font-family:var(--font-head); font-size:13.5px; color:var(--ink-faint); padding:18px 0 0; }
.crumb a{ color:var(--ink-soft); text-decoration:none; }
.crumb a:hover{ color:var(--accent); }
.dp-hero{ display:grid; grid-template-columns:auto 1fr; gap:32px; align-items:center; padding:26px 0 34px; }
.dp-icon{ width:132px; height:132px; border-radius:30px; overflow:hidden;
  box-shadow:0 12px 28px rgba(0,0,0,.18); border:1px solid rgba(0,0,0,.06); }
.dp-icon img{ width:100%; height:100%; object-fit:cover; }
.dp-kicker{ font-family:var(--font-hand); font-size:23px; color:var(--c,var(--accent)); transform:rotate(-1.5deg); display:inline-block; }
.dp-name{ font-family:var(--font-display); font-weight:800; font-size:clamp(34px,5.4vw,54px); letter-spacing:-.02em; line-height:1; margin:4px 0 12px; }
.dp-lead{ font-size:18px; line-height:1.55; color:var(--ink-soft); max-width:560px; margin:0 0 18px; }
.dp-meta{ display:flex; gap:16px; align-items:center; flex-wrap:wrap; font-family:var(--font-head); font-size:14px; color:var(--ink-faint); margin-bottom:20px; }
.dp-meta b{ color:var(--ink); }
.dp-meta .star{ color:#E0A92E; letter-spacing:1px; }
.dp-card{ background:#fff; border:2px solid var(--c,#1d2438); border-radius:var(--radius);
  box-shadow:6px 6px 0 color-mix(in srgb,var(--c,#1d2438) 24%,transparent); padding:30px; }
.feat{ display:flex; gap:15px; align-items:flex-start; }
.feat .fn{ font-family:var(--font-hand); font-size:30px; color:var(--c,var(--accent)); line-height:1; min-width:36px; }
.feat h3{ font-family:var(--font-head); font-weight:600; font-size:18px; margin:2px 0 5px; }
.feat p{ font-size:15px; line-height:1.6; color:var(--ink-soft); margin:0; }
.chips{ display:flex; flex-wrap:wrap; gap:10px; }
.chip{ font-family:var(--font-head); font-size:14px; color:var(--ink); background:#fff;
  border:1.5px solid color-mix(in srgb,var(--c,#1d2438) 45%,#cfd4df); border-radius:30px; padding:8px 15px; }
.faq{ border-top:1px dashed #d4d8e2; }
.faq details{ border-bottom:1px dashed #d4d8e2; padding:4px 0; }
.faq summary{ list-style:none; cursor:pointer; font-family:var(--font-head); font-weight:600;
  font-size:17px; padding:16px 36px 16px 2px; position:relative; color:var(--ink); }
.faq summary::-webkit-details-marker{ display:none; }
.faq summary::after{ content:'+'; position:absolute; right:6px; top:13px; font-size:24px; font-weight:400; color:var(--c,var(--accent)); transition:transform .2s ease; }
.faq details[open] summary::after{ content:'\2013'; }
.faq p{ font-size:15.5px; line-height:1.6; color:var(--ink-soft); margin:0 2px 16px; max-width:680px; }
.related{ display:grid; grid-template-columns:repeat(6,1fr); gap:14px; }
.rel{ display:flex; flex-direction:column; align-items:center; gap:8px; text-decoration:none; color:var(--ink-soft); }
.rel img{ width:58px; height:58px; border-radius:14px; box-shadow:0 3px 7px rgba(0,0,0,.15); }
.rel span{ font-family:var(--font-head); font-size:12.5px; text-align:center; line-height:1.2; }
.rel:hover{ color:var(--accent); }
.keys{ list-style:none; margin:0; padding:0; display:grid; grid-template-columns:1fr 1fr; gap:13px 26px; }
.keys li{ display:flex; align-items:flex-start; gap:11px; font-size:15.5px; line-height:1.45; color:var(--ink-soft); }
.keys li b{ color:var(--ink); font-weight:700; }
.keys .tick{ flex:none; width:24px; height:24px; border-radius:7px; background:color-mix(in srgb,var(--c,#1d2438) 14%,#fff);
  color:var(--c,var(--accent)); display:flex; align-items:center; justify-content:center; font-size:14px; font-weight:800; margin-top:1px; }
@media (max-width:680px){ .keys{ grid-template-columns:1fr; } }

/* ---------- mobile polish ---------- */
html, body{ overflow-x:hidden; max-width:100%; }
/* hide Italian-only apps (Diritto, Analisi Grammaticale, Analisi Logica) in non-Italian UI */
html:not([lang="it"]) .app-card[data-itonly="1"]{ display:none !important; }
@media (max-width:560px){
  .wrap{ padding:0 18px; }
  .nav-in{ padding:12px 18px; gap:12px; }
  .brand b{ font-size:18px; }
  .app-card{ padding:15px; }
  .app-foot{ flex-direction:column; align-items:stretch; gap:8px; }
  .cardbtn{ width:100%; padding:11px 10px; font-size:13.5px; }
  .stat{ min-width:0; }
  .stat .n{ font-size:28px; }
  .stores{ gap:10px; }
  .storebtn{ flex:1 1 auto; justify-content:center; }
  .dp-icon{ width:108px; height:108px; }
}
@media (max-width:380px){
  .app-grid{ grid-template-columns:1fr; }
  .related{ grid-template-columns:repeat(2,1fr); }
}
@media (max-width:680px){
  .dp-hero{ grid-template-columns:1fr; text-align:center; justify-items:center; }
  .dp-lead{ margin-inline:auto; } .dp-meta{ justify-content:center; } .stores{ justify-content:center; }
  .related{ grid-template-columns:repeat(3,1fr); }
}