:root{
  color-scheme:light;
  --ink:#17233f;
  --muted:#5b6b87;
  --navy:#153a73;
  --blue:#2563eb;
  --blue-soft:#eaf2ff;
  --orange:#f97316;
  --orange-soft:#fff1e7;
  --pink:#e83e8c;
  --green:#087f5b;
  --green-soft:#e8fff6;
  --red:#c92a2a;
  --line:#d7e1f1;
  --card:#ffffff;
  font-family:"Segoe UI",Arial,sans-serif;
}

*{box-sizing:border-box;}

html,
body{min-height:100%;}

body{
  margin:0;
  overflow-x:hidden;
  background:
    radial-gradient(circle at 8% 0%, rgba(249,115,22,.12), transparent 26rem),
    radial-gradient(circle at 100% 8%, rgba(37,99,235,.13), transparent 28rem),
    #f7faff;
  color:var(--ink);
}

button,
a{font:inherit;}

button{touch-action:manipulation;}

[hidden]{display:none!important;}

.angle-app{
  width:min(1220px,100%);
  margin:0 auto;
  padding:22px;
}

.angle-intro{
  display:grid;
  grid-template-columns:minmax(0,1fr) auto;
  gap:22px;
  align-items:start;
  padding:24px 26px;
  border:1px solid rgba(201,216,239,.95);
  border-radius:24px;
  background:rgba(255,255,255,.9);
  box-shadow:0 20px 55px rgba(45,73,118,.1);
}

.angle-intro__text{max-width:850px;}

.angle-eyebrow{
  margin:0 0 7px;
  color:var(--blue);
  font-size:.78rem;
  font-weight:900;
  letter-spacing:.12em;
}

.angle-intro h1{
  margin:0;
  font-size:clamp(1.65rem,3.3vw,2.75rem);
  line-height:1.08;
  letter-spacing:-.035em;
}

.angle-intro p:last-child{
  max-width:790px;
  margin:12px 0 0;
  color:var(--muted);
  font-size:1.02rem;
  line-height:1.65;
}

.angle-intro__actions{
  display:flex;
  gap:9px;
  align-items:center;
}

.angle-intro__link,
.angle-icon-button{
  display:inline-flex;
  min-height:46px;
  align-items:center;
  justify-content:center;
  border:1px solid #bed0ea;
  border-radius:14px;
  background:#fff;
  color:var(--navy);
  font-weight:800;
  text-decoration:none;
}

.angle-intro__link{padding:10px 15px;white-space:nowrap;}

.angle-icon-button{width:46px;padding:0;cursor:pointer;}
.angle-icon-button img{width:22px;height:22px;}

.angle-key{
  display:grid;
  grid-template-columns:repeat(3,minmax(0,1fr));
  gap:12px;
  margin-top:16px;
}

.angle-key article{
  display:grid;
  grid-template-columns:48px minmax(0,1fr);
  gap:12px;
  align-items:center;
  min-width:0;
  padding:14px 16px;
  border:1px solid var(--line);
  border-radius:18px;
  background:rgba(255,255,255,.82);
}

.angle-key article>span{
  display:grid;
  width:48px;
  height:48px;
  place-items:center;
  border-radius:15px;
  background:var(--orange-soft);
  color:var(--orange);
  font-size:1.45rem;
  font-weight:900;
}

.angle-key strong,
.angle-key small{display:block;}
.angle-key strong{font-size:.94rem;}
.angle-key small{margin-top:4px;color:var(--muted);line-height:1.35;}

.angle-examples{
  display:grid;
  grid-template-columns:repeat(4,minmax(0,1fr));
  gap:10px;
  margin:17px 0;
}

.angle-example{
  position:relative;
  display:grid;
  grid-template-columns:42px minmax(0,1fr);
  min-height:68px;
  gap:2px 10px;
  align-items:center;
  padding:9px 12px;
  border:1px solid #cbd8ec;
  border-radius:17px;
  background:#fff;
  color:var(--ink);
  text-align:left;
  cursor:pointer;
}

.angle-example>span{
  grid-row:1/3;
  display:grid;
  width:42px;
  height:42px;
  place-items:center;
  border-radius:13px;
  background:#edf3fc;
  color:var(--navy);
  font-weight:900;
}

.angle-example strong,
.angle-example small{min-width:0;}
.angle-example strong{align-self:end;font-size:.92rem;}
.angle-example small{align-self:start;color:var(--muted);}
.angle-example.is-active{border-color:#6e9ce9;background:var(--blue-soft);box-shadow:0 8px 22px rgba(37,99,235,.12);}
.angle-example.is-active>span{background:var(--blue);color:#fff;}

.angle-workspace{
  display:grid;
  grid-template-columns:minmax(0,1.48fr) minmax(300px,.72fr);
  gap:16px;
  align-items:start;
}

.angle-visual-card,
.angle-narration{
  min-width:0;
  border:1px solid var(--line);
  border-radius:22px;
  background:var(--card);
  box-shadow:0 16px 40px rgba(45,73,118,.09);
}

.angle-visual-card{overflow:hidden;}

.angle-visual-card__head{
  display:flex;
  gap:14px;
  align-items:flex-start;
  justify-content:space-between;
  padding:18px 20px 13px;
}

.angle-visual-card__head h2{
  margin:0;
  font-size:clamp(1.12rem,2.1vw,1.45rem);
}

.angle-step-count{
  flex:0 0 auto;
  padding:8px 11px;
  border-radius:999px;
  background:var(--blue-soft);
  color:var(--navy);
  font-weight:900;
}

.angle-progress{height:5px;background:#eaf0f8;}
.angle-progress i{display:block;width:20%;height:100%;background:linear-gradient(90deg,var(--orange),var(--pink));transition:width .35s ease;}

.angle-canvas{
  display:grid;
  min-height:380px;
  place-items:center;
  padding:8px 14px;
  background:
    linear-gradient(rgba(84,123,178,.055) 1px,transparent 1px),
    linear-gradient(90deg,rgba(84,123,178,.055) 1px,transparent 1px),
    #fbfdff;
  background-size:24px 24px;
}

.angle-canvas svg{display:block;width:100%;height:auto;max-height:440px;overflow:visible;}

.svg-main-line,
.svg-broken-line,
.svg-bisector{
  fill:none;
  stroke:var(--navy);
  stroke-linecap:round;
  stroke-linejoin:round;
}

.svg-main-line{stroke-width:4;}
.svg-broken-line{stroke-width:5;}
.svg-broken-line--bold{stroke-width:6;}
.svg-bisector{stroke:#356fb8;stroke-width:5;}
.svg-arrow{fill:var(--navy);stroke:none;}
.svg-parallel-mark{fill:none;stroke:#2d62ad;stroke-width:3;stroke-linecap:round;stroke-linejoin:round;}
.svg-point{fill:#fff;stroke:var(--navy);stroke-width:3;}
.svg-point-label,
.svg-line-label{fill:var(--ink);font-size:22px;font-weight:900;}
.svg-line-label{font-style:italic;}
.svg-angle{fill:none;stroke-width:4;stroke-linecap:round;}
.svg-angle.given{stroke:var(--pink);}
.svg-angle.unknown{stroke:var(--red);stroke-width:6;}
.svg-angle.copied{stroke:var(--orange);}
.svg-given-label,
.svg-unknown-label,
.svg-copy-label,
.svg-helper-label,
.svg-rule-label,
.svg-answer-label{
  paint-order:stroke fill;
  stroke:#fff;
  stroke-width:6px;
  stroke-linejoin:round;
  fill:var(--ink);
  font-size:20px;
  font-weight:900;
}
.svg-unknown-label{fill:var(--red);font-size:26px;}
.svg-copy-label,
.svg-helper-label{fill:#b94b09;}
.svg-helper-label{font-size:17px;}
.svg-rule-label{fill:var(--navy);font-size:21px;}
.svg-helper-line{
  fill:none;
  stroke:var(--orange);
  stroke-width:4;
  stroke-dasharray:12 10;
  stroke-linecap:round;
}
.svg-straight-brace{fill:none;stroke:#5a7fb6;stroke-width:3;stroke-linecap:round;}
.svg-focus-wedge{fill:rgba(232,62,140,.18);stroke:var(--pink);stroke-width:2;}
.svg-answer-angle{fill:none;stroke:var(--green);stroke-width:7;stroke-linecap:round;}
.svg-answer-box{fill:var(--green-soft);stroke:#45ad87;stroke-width:2;}
.svg-answer-label{fill:var(--green);stroke:var(--green-soft);font-size:22px;}
.angle-canvas.is-solved .svg-unknown-label{opacity:0;}

[data-reveal],
[data-answer]{
  opacity:0;
  transform:translateY(4px);
  transform-box:fill-box;
  transform-origin:center;
  transition:opacity .5s ease,transform .5s ease;
}

[data-answer]{visibility:hidden;}

[data-reveal].is-visible,
[data-answer].is-visible{opacity:1;transform:translateY(0);}

[data-answer].is-visible{visibility:visible;}

.svg-helper-line[data-reveal]{stroke-dasharray:12 10;}

.angle-controls{
  display:grid;
  grid-template-columns:repeat(4,minmax(0,1fr));
  gap:9px;
  padding:14px;
  border-top:1px solid #e5ecf6;
  background:#fff;
}

.angle-controls button,
.angle-quiz__choices button{
  min-height:46px;
  border:1px solid #bfd0e7;
  border-radius:13px;
  background:#fff;
  color:var(--navy);
  font-weight:850;
  cursor:pointer;
}

.angle-controls button.is-primary{border-color:#1f5fd0;background:var(--blue);color:#fff;}
.angle-controls button.is-quiet{border-style:dashed;}
.angle-controls button:disabled{cursor:not-allowed;opacity:.45;}

.angle-narration{
  display:grid;
  gap:15px;
  padding:20px;
}

.angle-narration__step{display:grid;grid-template-columns:46px minmax(0,1fr);gap:12px;align-items:center;}
.angle-narration__step>span{display:grid;width:46px;height:46px;place-items:center;border-radius:15px;background:linear-gradient(145deg,var(--orange),#fb4f86);color:#fff;font-size:1.2rem;font-weight:900;}
.angle-narration__step p{margin:0 0 4px;color:var(--blue);font-size:.7rem;font-weight:900;letter-spacing:.11em;}
.angle-narration__step h2{margin:0;font-size:1.18rem;line-height:1.25;}
.angle-narration__text{margin:0;color:#364765;font-size:1rem;line-height:1.65;}

.angle-why{
  padding:14px 15px;
  border-left:5px solid var(--orange);
  border-radius:0 15px 15px 0;
  background:var(--orange-soft);
}
.angle-why strong{display:block;color:#a33e06;}
.angle-why p{margin:4px 0 0;color:#63351f;line-height:1.55;}

.angle-equation{
  margin:0;
  padding:14px;
  border:1px solid #bdd0ee;
  border-radius:15px;
  background:var(--blue-soft);
  color:var(--navy);
  font-size:clamp(1.05rem,2vw,1.32rem);
  font-weight:900;
  text-align:center;
}

.angle-quiz{
  display:grid;
  gap:11px;
  padding-top:15px;
  border-top:1px solid var(--line);
}
.angle-quiz__eyebrow{margin:0;color:var(--pink);font-size:.72rem;font-weight:900;letter-spacing:.12em;}
.angle-quiz h3{margin:0;font-size:1.02rem;line-height:1.45;}
.angle-quiz__choices{display:grid;grid-template-columns:repeat(3,1fr);gap:9px;}
.angle-quiz__choices button{font-size:1.08rem;}
.angle-quiz__choices button.is-wrong{border-color:#f19a9a;background:#fff0f0;color:var(--red);}
.angle-quiz__choices button.is-correct{border-color:#45ad87;background:var(--green-soft);color:var(--green);}
.angle-quiz__feedback{padding:13px;border-radius:13px;line-height:1.5;}
.angle-quiz__feedback.is-hint{border:1px solid #f0c07d;background:#fff8e7;color:#744513;}
.angle-quiz__feedback.is-correct{border:1px solid #83cfb2;background:var(--green-soft);color:#075b43;}

.sr-only{position:absolute!important;width:1px!important;height:1px!important;padding:0!important;margin:-1px!important;overflow:hidden!important;clip:rect(0,0,0,0)!important;white-space:nowrap!important;border:0!important;}

:focus-visible{outline:3px solid #f59e0b;outline-offset:3px;}

@media (max-width:980px){
  .angle-intro{grid-template-columns:1fr;}
  .angle-intro__actions{justify-content:flex-start;}
  .angle-examples{grid-template-columns:repeat(2,minmax(0,1fr));}
  .angle-workspace{grid-template-columns:1fr;}
  .angle-narration{grid-template-columns:minmax(0,1fr) minmax(0,1fr);align-items:start;}
  .angle-narration__step,
  .angle-narration__text{grid-column:1;}
  .angle-why,
  .angle-equation,
  .angle-quiz{grid-column:2;}
  .angle-why{grid-row:1/3;}
}

@media (max-width:720px){
  .angle-app{padding:12px;}
  .angle-intro{padding:18px;border-radius:19px;}
  .angle-intro__actions{flex-wrap:wrap;}
  .angle-intro__link{flex:1 1 170px;}
  .angle-key{grid-template-columns:1fr;}
  .angle-key article{padding:11px 13px;}
  .angle-examples{grid-template-columns:1fr 1fr;}
  .angle-example{grid-template-columns:38px minmax(0,1fr);padding:8px;}
  .angle-example>span{width:38px;height:38px;}
  .angle-visual-card__head{padding:15px;}
  .angle-canvas{min-height:300px;padding:5px;}
  .angle-controls{grid-template-columns:1fr 1fr;}
  .angle-narration{grid-template-columns:1fr;padding:16px;}
  .angle-narration__step,
  .angle-narration__text,
  .angle-why,
  .angle-equation,
  .angle-quiz{grid-column:1;grid-row:auto;}
}

@media (max-width:430px){
  .angle-examples{grid-template-columns:1fr;}
  .angle-step-count{font-size:.86rem;}
  .angle-canvas{min-height:255px;}
  .angle-controls{grid-template-columns:1fr;}
}

@media (prefers-reduced-motion:reduce){
  *,*::before,*::after{scroll-behavior:auto!important;transition-duration:.01ms!important;animation-duration:.01ms!important;animation-iteration-count:1!important;}
}

html:fullscreen body,
html:-webkit-full-screen body{overflow:auto;}

html:fullscreen .angle-app,
html:-webkit-full-screen .angle-app{width:min(1400px,100%);}