/* Dal transistor al codice — shared visual language for every module.
   A tribute to Olivetti's desktop machines (Programma 101): warm putty
   chassis, engraved labels, mechanical keycaps, and dark phosphor-green
   display insets for everything the machine "shows". */

:root {
  --chassis: #e3ddcd;
  --chassis-deep: #d3ccb8;
  --panel: #f1ede1;
  --panel-edge: #c4bca6;
  --ink: #34322b;
  --ink-soft: #7c7663;
  --olivetti: #c8442c;
  --olivetti-dark: #a83620;
  --screen: #20251e;
  --screen-edge: #14170f;
  --phosphor: #93e8bb;
  --phosphor-dim: #5d8f74;
  --phosphor-soft: #b9f0d3;
  --amber: #e4b04a;
  --led-off: #4a3f38;
  --pass: #3d7a4f;
  --fail: #b23a2c;
  --mono: ui-monospace, "SF Mono", "Cascadia Mono", "JetBrains Mono", Menlo, Consolas, monospace;
  --sans: "Avenir Next", "Segoe UI", system-ui, -apple-system, sans-serif;
}

* { box-sizing: border-box; margin: 0; padding: 0; }

[hidden] { display: none !important; }

html, body { height: 100%; }

body {
  font-family: var(--sans);
  color: var(--ink);
  background:
    radial-gradient(ellipse at 30% -10%, #efeadb 0%, var(--chassis) 55%, var(--chassis-deep) 100%);
  display: flex;
  flex-direction: column;
}

button { font: inherit; cursor: pointer; }

a { color: var(--olivetti-dark); }

/* ---------- header ---------- */

.top {
  display: flex;
  align-items: center;
  justify-content: space-between;
  gap: 1rem;
  padding: 0.7rem 1.2rem;
  border-bottom: 2px solid var(--panel-edge);
  flex-wrap: wrap;
}

.brand { display: flex; align-items: center; gap: 0.75rem; }

a.brand { text-decoration: none; color: inherit; }

.brand-mark {
  font-family: var(--mono);
  font-weight: 700;
  font-size: 0.9rem;
  color: var(--panel);
  background: var(--olivetti);
  border-radius: 6px;
  padding: 0.45rem 0.5rem;
  letter-spacing: 0.05em;
  box-shadow: inset 0 -2px 0 rgb(0 0 0 / 0.25);
}

.brand-text h1 {
  font-family: var(--mono);
  font-size: 1.15rem;
  letter-spacing: 0.06em;
  line-height: 1.1;
}

.brand-sub {
  font-size: 0.62rem;
  letter-spacing: 0.32em;
  color: var(--ink-soft);
  font-weight: 600;
  vertical-align: 0.15em;
}

.brand-tag { font-size: 0.72rem; color: var(--ink-soft); font-style: italic; }

.top-nav { display: flex; align-items: center; gap: 0.5rem; }

.lang-switch {
  display: flex;
  border: 1px solid var(--panel-edge);
  border-radius: 6px;
  overflow: hidden;
  margin-left: 0.4rem;
}

.lang-switch button {
  border: 0;
  background: var(--panel);
  color: var(--ink-soft);
  font-size: 0.7rem;
  font-weight: 700;
  letter-spacing: 0.08em;
  padding: 0.35rem 0.55rem;
}

.lang-switch button.active { background: var(--ink); color: var(--panel); }

/* ---------- keycap buttons ---------- */

.btn {
  font-size: 0.78rem;
  font-weight: 600;
  letter-spacing: 0.06em;
  color: var(--ink);
  background: linear-gradient(#faf7ee, #eae5d5);
  border: 1px solid var(--panel-edge);
  border-radius: 7px;
  padding: 0.42rem 0.85rem;
  box-shadow: 0 2px 0 var(--panel-edge), 0 3px 4px rgb(0 0 0 / 0.08);
  transition: transform 60ms, box-shadow 60ms;
  text-decoration: none;
  display: inline-block;
}

.btn:hover { filter: brightness(1.03); }

.btn:active {
  transform: translateY(2px);
  box-shadow: 0 0 0 var(--panel-edge);
}

.btn:disabled { opacity: 0.45; cursor: default; transform: none; }

.btn-primary {
  color: #fff;
  background: linear-gradient(#d9563c, var(--olivetti));
  border-color: var(--olivetti-dark);
  box-shadow: 0 2px 0 var(--olivetti-dark), 0 3px 4px rgb(0 0 0 / 0.15);
}

.btn-ghost {
  background: transparent;
  box-shadow: none;
  border-color: transparent;
  color: var(--ink-soft);
}

.btn-ghost:active { transform: none; }

:focus-visible { outline: 2px solid var(--olivetti); outline-offset: 2px; }

/* ---------- cards & engraved labels ---------- */

.card {
  background: var(--panel);
  border: 1px solid var(--panel-edge);
  border-radius: 10px;
  box-shadow: 0 1px 0 #fff inset, 0 4px 10px rgb(60 50 20 / 0.08);
  padding: 0.7rem 0.8rem 0.8rem;
}

.card-head {
  display: flex;
  align-items: center;
  justify-content: space-between;
  flex-wrap: wrap;
  gap: 0.5rem;
  margin-bottom: 0.55rem;
}

.card-title, .io-label, .lesson-eyebrow {
  font-size: 0.62rem;
  font-weight: 700;
  letter-spacing: 0.26em;
  text-transform: uppercase;
  color: var(--ink-soft);
  text-shadow: 0 1px 0 rgb(255 255 255 / 0.7);
}

.chip {
  border-radius: 4px;
  padding: 0.08rem 0.45rem;
  white-space: nowrap;
}

.chip-rule {
  font-family: var(--mono);
  font-size: 0.68rem;
  background: var(--chassis-deep);
  border: 1px solid var(--panel-edge);
  color: var(--ink);
}

/* ---------- lesson panel ---------- */

.lesson { display: flex; flex-direction: column; gap: 0.7rem; }

.lesson-eyebrow { display: flex; align-items: center; gap: 0.5rem; }

.lesson-title { font-size: 1.25rem; line-height: 1.2; }

.lesson-text { font-size: 0.86rem; line-height: 1.55; }

.lesson-text code, .goal code, .hint code, .help-body code {
  font-family: var(--mono);
  font-size: 0.85em;
  background: rgb(60 50 20 / 0.08);
  border-radius: 4px;
  padding: 0.05em 0.3em;
}

.lesson-text pre, .help-body pre {
  font-family: var(--mono);
  font-size: 0.78rem;
  line-height: 1.5;
  background: var(--screen);
  color: var(--phosphor);
  border-radius: 7px;
  padding: 0.6rem 0.8rem;
  overflow-x: auto;
  margin: 0.4rem 0;
}

.lesson-text pre code, .help-body pre code { background: none; color: inherit; padding: 0; }

.goal {
  font-size: 0.86rem;
  line-height: 1.5;
  background: rgb(200 68 44 / 0.07);
  border-left: 3px solid var(--olivetti);
  border-radius: 0 7px 7px 0;
  padding: 0.5rem 0.7rem;
}

.goal-label {
  display: block;
  font-size: 0.6rem;
  font-weight: 700;
  letter-spacing: 0.26em;
  text-transform: uppercase;
  color: var(--olivetti);
  margin-bottom: 0.15rem;
}

.rule-chips { display: flex; flex-wrap: wrap; gap: 0.3rem; }

.hints { display: flex; flex-direction: column; gap: 0.4rem; align-items: flex-start; }

.hint {
  font-size: 0.82rem;
  line-height: 1.5;
  background: rgb(228 176 74 / 0.14);
  border-left: 3px solid var(--amber);
  border-radius: 0 7px 7px 0;
  padding: 0.45rem 0.65rem;
}

.banner {
  border-radius: 8px;
  padding: 0.7rem 0.8rem;
  font-size: 0.86rem;
  font-weight: 600;
  display: flex;
  flex-direction: column;
  gap: 0.55rem;
}

.banner-pass { background: rgb(61 122 79 / 0.12); border: 1px solid var(--pass); color: var(--pass); }
.banner-fail { background: rgb(178 58 44 / 0.1); border: 1px solid var(--fail); color: var(--fail); }

.done-mark { color: var(--pass); font-weight: 700; }

.btn-reset-code { align-self: flex-start; font-size: 0.68rem; }
.btn-hint { font-size: 0.72rem; border: 1px dashed var(--panel-edge); }

/* ---------- modals ---------- */

.overlay {
  position: fixed;
  inset: 0;
  background: rgb(40 35 20 / 0.45);
  display: flex;
  align-items: center;
  justify-content: center;
  padding: 1rem;
  z-index: 10;
}

.modal {
  background: var(--panel);
  border: 1px solid var(--panel-edge);
  border-radius: 12px;
  box-shadow: 0 20px 60px rgb(0 0 0 / 0.3);
  max-width: 860px;
  width: 100%;
  max-height: 88vh;
  overflow-y: auto;
  padding: 1rem 1.2rem 1.2rem;
}

.modal-head {
  display: flex;
  align-items: center;
  justify-content: space-between;
  margin-bottom: 0.8rem;
}

.modal-head h2 { font-size: 1.1rem; letter-spacing: 0.02em; }

.level-cards {
  display: grid;
  grid-template-columns: repeat(auto-fill, minmax(180px, 1fr));
  gap: 0.6rem;
}

.level-card {
  position: relative;
  display: flex;
  flex-direction: column;
  align-items: flex-start;
  gap: 0.25rem;
  text-align: left;
  background: linear-gradient(#faf7ee, #eee9da);
  border: 1px solid var(--panel-edge);
  border-radius: 9px;
  padding: 0.7rem 0.8rem;
  box-shadow: 0 2px 0 var(--panel-edge);
  transition: transform 80ms;
}

.level-card:hover { transform: translateY(-2px); }

.level-card.current { border-color: var(--olivetti); box-shadow: 0 2px 0 var(--olivetti); }

.level-card .level-num {
  font-family: var(--mono);
  font-size: 0.7rem;
  font-weight: 700;
  color: var(--olivetti);
  letter-spacing: 0.1em;
}

.level-card .level-name { font-weight: 600; font-size: 0.85rem; }

.level-card .level-desc { font-size: 0.72rem; color: var(--ink-soft); }

.level-card .done-mark { position: absolute; top: 0.55rem; right: 0.7rem; }

.level-card.done { background: linear-gradient(#f2f7ee, #e4ecdc); }

.sandbox-card { border-style: dashed; }

.help-body { font-size: 0.86rem; line-height: 1.55; }

.help-body h3 {
  font-size: 0.66rem;
  font-weight: 700;
  letter-spacing: 0.26em;
  text-transform: uppercase;
  color: var(--olivetti);
  margin: 1rem 0 0.4rem;
}

.help-body p { margin-bottom: 0.5rem; }

.help-body table { border-collapse: collapse; width: 100%; font-size: 0.8rem; }

.help-body th, .help-body td {
  text-align: left;
  padding: 0.3rem 0.5rem;
  border-bottom: 1px solid rgb(60 50 20 / 0.12);
}

.help-body th {
  font-size: 0.62rem;
  letter-spacing: 0.2em;
  text-transform: uppercase;
  color: var(--ink-soft);
}

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