/* Learn page */
.learn { display: grid; grid-template-columns: 250px minmax(0, 1fr); gap: 44px; align-items: start; }
.side { position: sticky; top: 84px; max-height: calc(100vh - 100px); overflow: auto; padding-bottom: 10px; }
.progress { display: flex; align-items: center; gap: 10px; margin-bottom: 14px; font-size: .8rem; color: var(--muted); }
.progress .bar { flex: 1; height: 6px; border-radius: 99px; background: var(--line); overflow: hidden; }
.progress .bar i { display: block; height: 100%; width: 0; background: linear-gradient(90deg, var(--gold2), var(--gold)); border-radius: 99px; transition: width .5s; }
#toc { display: grid; gap: 2px; }
#toc a { display: flex; align-items: center; gap: 10px; padding: 8px 10px; border-radius: 10px; color: var(--muted); text-decoration: none; font-size: .93rem; border-inline-start: 2px solid transparent; transition: all .2s; }
#toc a:hover { color: var(--ink); background: var(--card); }
#toc a.cur { color: var(--ink); border-inline-start-color: var(--gold); background: var(--card); }
#toc .n { font: 500 .72rem var(--mono); width: 22px; height: 22px; flex: none; border-radius: 50%; border: 1px solid var(--line); display: grid; place-items: center; }
#toc a.done .n { background: var(--ok); border-color: var(--ok); color: var(--bg); }

.mod { padding: 10px 0 64px; border-bottom: 1px solid var(--line); margin-bottom: 54px; }
.mod:last-child { border-bottom: 0; }
.mod-n { font: 600 .8rem var(--mono); color: var(--hl); letter-spacing: .14em; }
.mod h2 { font-size: clamp(1.6rem, 3vw, 2.2rem); margin: 6px 0 12px; }
.mod .lead { margin-bottom: 24px; }
.mod h3.sub { font-size: 1.15rem; margin: 30px 0 12px; }
.done-btn { margin-top: 28px; }
.done-btn.is { background: transparent; color: var(--ok); border-color: var(--ok); }

/* Objectives */
.obj { position: relative; padding-top: 44px; }
.obj .k { position: absolute; top: 16px; inset-inline-start: 24px; font: 700 1.1rem "Chakra Petch", sans-serif; color: var(--hl); }
.obj h3 { font-size: 1.1rem; margin-bottom: 8px; }
.obj p { color: var(--muted); font-size: .93rem; }
.obj .m { display: block; font: 500 .8rem var(--mono); color: var(--hl); padding-top: 12px; border-top: 1px dashed var(--line); }
:root[data-lang="ar"] .obj .m { font-family: var(--body); font-size: .88rem; }

/* Anatomy */
.plan { background: var(--card); border: 1px solid var(--line); border-radius: 18px; padding: 16px; margin-top: 14px; }
.plan svg { width: 100%; height: auto; display: block; }
.plan .shell { fill: var(--bg2); stroke: var(--line); stroke-width: 2; }
.plan .p rect { fill: color-mix(in srgb, var(--gold) 14%, var(--card)); stroke: var(--gold); stroke-width: 1.4; cursor: pointer; transition: fill .2s; }
.plan .p.dash rect { stroke-dasharray: 7 5; fill: color-mix(in srgb, var(--gold) 5%, transparent); }
.plan .p:hover rect, .plan .p.sel rect { fill: var(--gold); }
.plan .p text { fill: var(--ink); font: 500 11px var(--body); text-anchor: middle; pointer-events: none; }
.plan .p:hover text, .plan .p.sel text { fill: #141414; }
.plan-info { display: grid; grid-template-columns: 110px 1fr; gap: 16px; align-items: center; margin-top: 14px; min-height: 100px; }
.plan-info img { border-radius: 12px; background: #fff; aspect-ratio: 4/3; object-fit: contain; }
.plan-info h4 { font-size: 1.05rem; margin-bottom: 4px; }
.plan-info p { margin: 0; color: var(--muted); font-size: .93rem; }
.plan-info.noimg { grid-template-columns: 1fr; }

/* Parts */
.toolbar { display: flex; flex-wrap: wrap; gap: 12px; align-items: center; margin-bottom: 18px; }
.search { flex: 1; min-width: 200px; padding: 10px 16px; border-radius: 999px; border: 1px solid var(--line); background: var(--card); color: var(--ink); font: inherit; }
.parts { display: grid; grid-template-columns: repeat(auto-fill, minmax(170px, 1fr)); gap: 14px; }
.part { padding: 0; overflow: hidden; border-radius: 16px; }
.part .ph { background: #fff; aspect-ratio: 4/3; display: grid; place-items: center; }
.part .ph img { width: 100%; height: 100%; object-fit: contain; }
.part .tx { padding: 12px 14px 14px; }
.part b { display: block; font: 600 .93rem var(--body); line-height: 1.3; direction: ltr; text-align: start; }
.part small { color: var(--muted); font-size: .78rem; }
.empty { color: var(--muted); padding: 30px; text-align: center; grid-column: 1/-1; }
.pm { display: grid; grid-template-columns: minmax(0, 260px) minmax(0, 1fr); gap: 22px; align-items: start; }
.pm img { background: #fff; border-radius: 14px; width: 100%; }
.pm h3 { font-size: 1.4rem; margin: 6px 0 10px; direction: ltr; text-align: start; }
.pm .spec { font: 400 .82rem var(--mono); color: var(--hl); direction: ltr; text-align: start; margin-bottom: 12px; }

/* Power */
.chain { display: flex; flex-wrap: wrap; gap: 8px; align-items: stretch; }
.chain .step { flex: 1 1 120px; background: var(--card); border: 1px solid var(--line); border-radius: 14px; padding: 12px; position: relative; cursor: default; transition: border-color .2s, transform .2s; }
.chain .step:hover { border-color: var(--gold); transform: translateY(-3px); }
.chain .step b { display: block; font: 600 .95rem var(--display); color: var(--hl); margin-bottom: 4px; }
.chain .step span { font-size: .8rem; color: var(--muted); line-height: 1.4; display: block; }
.chain .step em { position: absolute; top: -9px; inset-inline-start: 12px; font: 500 .65rem var(--mono); font-style: normal; background: var(--bg); color: var(--muted); padding: 0 6px; border: 1px solid var(--line); border-radius: 6px; }
.calc { display: grid; grid-template-columns: minmax(0, 1fr) minmax(0, 220px); gap: 26px; align-items: center; margin-top: 16px; }
.calc input[type=range] { width: 100%; accent-color: var(--gold2); direction: ltr; }
.calc .marks { display: flex; justify-content: space-between; font: 400 .72rem var(--mono); color: var(--muted); direction: ltr; }
.calc .presets { margin-top: 14px; }
.gauge { text-align: center; }
.gauge b { font: 700 3.4rem/1 "Chakra Petch", sans-serif; color: var(--hl); display: block; direction: ltr; }
.gauge span { color: var(--muted); font-size: .9rem; }
.batt { height: 16px; border-radius: 99px; background: var(--line); overflow: hidden; margin: 14px 0 8px; direction: ltr; }
.batt i { display: block; height: 100%; border-radius: 99px; background: linear-gradient(90deg, var(--gold2), var(--gold)); transition: width .3s, background .3s; }
.batt i.low { background: var(--bad); }

/* Software */
.sw-layer { margin-bottom: 14px; }
.sw-layer > span { font: 500 .74rem var(--mono); letter-spacing: .1em; text-transform: uppercase; color: var(--muted); display: block; margin-bottom: 8px; }
:root[data-lang="ar"] .sw-layer > span { font-family: var(--body); letter-spacing: 0; font-size: .88rem; }
.sw-row { display: flex; flex-wrap: wrap; gap: 8px; }
.sw { padding: 10px 16px; border-radius: 12px; border: 1px solid var(--line); background: var(--card); color: var(--ink); font: 500 .92rem var(--body); cursor: pointer; transition: all .2s; }
.sw:hover { border-color: var(--gold); }
.sw[aria-pressed="true"] { background: var(--accent); color: var(--accent-ink); border-color: var(--accent); }
.sw-info { margin-top: 12px; min-height: 96px; }
.sw-info code { font: 400 .82rem var(--mono); color: var(--hl); direction: ltr; unicode-bidi: isolate; }
.sw-info p { margin: 6px 0 0; color: var(--muted); }

/* Drone chain */
.dchain { display: grid; gap: 0; }
.dstep { display: grid; grid-template-columns: 44px 1fr; gap: 16px; }
.dstep .rail { display: grid; justify-items: center; grid-template-rows: 44px 1fr; }
.dstep .rail i { width: 44px; height: 44px; border-radius: 50%; display: grid; place-items: center; border: 1px solid var(--gold); color: var(--hl); font: 600 .9rem var(--mono); font-style: normal; background: var(--card); }
.dstep .rail u { width: 1px; background: var(--line); min-height: 34px; position: relative; text-decoration: none; }
.dstep .rail u::after { content: attr(data-l); position: absolute; top: 50%; inset-inline-start: 12px; transform: translateY(-50%); font: 500 .68rem var(--mono); color: var(--muted); white-space: nowrap; }
.dstep .tx { padding: 8px 0 30px; }
.dstep h4 { font-size: 1.05rem; margin-bottom: 4px; }
.dstep p { margin: 0; color: var(--muted); font-size: .93rem; padding-inline-start: 0; }
.dstep:last-child .rail u { display: none; }

/* Diagrams */
.figs { display: grid; grid-template-columns: repeat(auto-fill, minmax(220px, 1fr)); gap: 14px; }
.fig { padding: 0; overflow: hidden; }
.fig .paper { background: #fff; aspect-ratio: 16/10; display: grid; place-items: center; padding: 8px; }
.fig .paper img { max-height: 100%; width: auto; max-width: 100%; }
.fig span { display: block; padding: 10px 14px; font-size: .88rem; }
.modal .box.wide { max-width: 1200px; }
.modal .box.wide img { width: 100%; background: #fff; border-radius: 12px; }
.fig-note { color: var(--muted); font-size: .85rem; margin-top: 10px; }

/* Safety */
.safe { display: grid; gap: 12px; }
.safe .card { display: grid; grid-template-columns: 12px 1fr; gap: 16px; padding: 18px 20px; }
.safe .pip { width: 12px; border-radius: 99px; background: var(--ok); }
.safe .bad .pip { background: var(--bad); } .safe .warn .pip { background: var(--warn); }
.safe h3 { font-size: 1.05rem; margin-bottom: 4px; }
.safe p { margin: 0; color: var(--muted); font-size: .93rem; }

/* Glossary */
.gloss { display: grid; grid-template-columns: repeat(auto-fill, minmax(260px, 1fr)); gap: 12px; }
.gloss .card { padding: 16px 18px; }
.gloss b { font: 600 1rem var(--mono); color: var(--hl); direction: ltr; display: block; text-align: start; }
.gloss p { margin: 4px 0 0; color: var(--muted); font-size: .9rem; }

/* Quiz */
.quiz .card { max-width: 720px; }
.quiz .qn { font: 500 .78rem var(--mono); color: var(--muted); }
.quiz h3 { font-size: 1.25rem; margin: 8px 0 16px; }
.quiz .opts { display: grid; gap: 8px; }
.quiz .opt { text-align: start; padding: 12px 16px; border-radius: 12px; border: 1px solid var(--line); background: var(--bg2); color: var(--ink); font: inherit; cursor: pointer; transition: all .2s; }
.quiz .opt:hover:not(:disabled) { border-color: var(--gold); }
.quiz .opt.right { border-color: var(--ok); background: color-mix(in srgb, var(--ok) 16%, transparent); }
.quiz .opt.wrong { border-color: var(--bad); background: color-mix(in srgb, var(--bad) 14%, transparent); }
.quiz .why { margin: 14px 0; color: var(--muted); min-height: 2.6em; }
.quiz .score b { font: 700 3.4rem "Chakra Petch", sans-serif; color: var(--hl); display: block; direction: ltr; text-align: start; }

@media (max-width: 900px) {
  .learn { grid-template-columns: minmax(0, 1fr); gap: 20px; }
  .side { position: static; max-height: none; }
  #toc { grid-template-columns: repeat(auto-fill, minmax(150px, 1fr)); }
  .calc, .pm { grid-template-columns: minmax(0, 1fr); }
}

/* Phones */
.swipe-hint { display: none; color: var(--muted); font-size: .8rem; margin: 6px 0 0; }
@media (max-width: 700px) { .swipe-hint { display: block; } }
@media (max-width: 600px) {
  .parts { grid-template-columns: repeat(2, minmax(0, 1fr)); gap: 10px; }
  .part .tx { padding: 9px 10px 11px; }
  .part b { font-size: .84rem; }
  /* The case drawing keeps a readable size and scrolls sideways instead of shrinking. */
  .plan { overflow-x: auto; }
  .plan svg { min-width: 520px; }
  .plan-info { grid-template-columns: 84px 1fr; }
  .dstep .rail u::after { display: none; }
}