/* PyDaily · playful "notebook meets arcade" theme.
   Thick ink outlines + hard offset shadows, Python yellow and blue. */
:root {
  --bg: #fbf5e6;
  --bg-dot: #e9dfc4;
  --panel: #ffffff;
  --panel-2: #fff9ea;
  --ink: #15171e;
  --muted: #5d6272;
  --line: #15171e;
  --soft: #ece4cf;
  --shadow: #15171e;
  --yellow: #ffd43b;
  --yellow-ink: #15171e;
  --blue: #3776ab;
  --blue-soft: #dceaf7;
  --green: #22a565;
  --green-soft: #d8f3e4;
  --red: #e5484d;
  --red-soft: #fde2e2;
  --purple: #7b5cff;
  --code-bg: #171a23;
  --code-ink: #e9e7df;
  --code-line: #2a2f3d;
  --radius: 16px;
  --sh: 4px 4px 0 var(--shadow);
  --sh-sm: 2px 2px 0 var(--shadow);
}
:root[data-theme="dark"] {
  --bg: #0f1117; --bg-dot: #1d212c; --panel: #181b24; --panel-2: #1d212c;
  --ink: #f1eee4; --muted: #9da3b3; --line: #3b4254; --soft: #262b38; --shadow: #000000;
  --blue: #6ea8dc; --blue-soft: #1b2a3b; --green: #3ccf86; --green-soft: #15301f;
  --red: #ff6b6f; --red-soft: #3a1a1c; --purple: #a08bff; --code-bg: #0b0d12; --code-line: #232836;
}
@media (prefers-color-scheme: dark) {
  :root:not([data-theme="light"]) {
    --bg: #0f1117; --bg-dot: #1d212c; --panel: #181b24; --panel-2: #1d212c;
    --ink: #f1eee4; --muted: #9da3b3; --line: #3b4254; --soft: #262b38; --shadow: #000000;
    --blue: #6ea8dc; --blue-soft: #1b2a3b; --green: #3ccf86; --green-soft: #15301f;
    --red: #ff6b6f; --red-soft: #3a1a1c; --purple: #a08bff; --code-bg: #0b0d12; --code-line: #232836;
  }
}

* { box-sizing: border-box; }
html, body { margin: 0; }
html { scroll-padding-top: 130px; }
body {
  background-color: var(--bg);
  background-image: radial-gradient(var(--bg-dot) 1.2px, transparent 1.2px);
  background-size: 22px 22px;
  color: var(--ink);
  font: 16px/1.6 Inter, system-ui, sans-serif;
  -webkit-font-smoothing: antialiased;
}
a { color: var(--blue); }
h1, h2, h3, h4, .display { font-family: "Space Grotesk", Inter, sans-serif; line-height: 1.15; letter-spacing: -.01em; }
code, pre, textarea, kbd, .mono { font-family: "JetBrains Mono", ui-monospace, monospace; }
kbd { font-size: .72rem; border: 1.5px solid var(--line); border-bottom-width: 3px; border-radius: 6px; padding: 0 5px; background: var(--panel); color: var(--ink); }
:focus-visible { outline: 3px solid var(--blue); outline-offset: 2px; }
[hidden] { display: none !important; }

/* ───────── top bar ───────── */
.topbar {
  position: sticky; top: 0; z-index: 40;
  display: flex; align-items: center; gap: 10px;
  padding: 10px clamp(12px, 3vw, 24px);
  background: var(--panel); border-bottom: 2px solid var(--line);
}
.brand { font: 700 1.35rem "Space Grotesk", sans-serif; color: var(--ink); text-decoration: none; display: flex; align-items: center; gap: 6px; }
.logo {
  background: var(--yellow); color: var(--yellow-ink); border: 2px solid var(--line); box-shadow: var(--sh-sm);
  border-radius: 9px; padding: 0 7px; font-size: 1.05rem; transform: rotate(-4deg); display: inline-block;
}
.icon-btn {
  background: var(--panel); border: 2px solid var(--line); color: var(--ink); border-radius: 10px;
  width: 40px; height: 40px; cursor: pointer; display: grid; place-items: center; flex-shrink: 0;
  transition: transform .1s, box-shadow .1s;
}
.icon-btn:hover { box-shadow: var(--sh-sm); transform: translate(-1px, -1px); }
.search-btn {
  display: flex; align-items: center; gap: 8px; margin-left: 8px;
  background: var(--panel-2); border: 2px solid var(--line); border-radius: 10px; color: var(--muted);
  padding: 7px 10px; cursor: pointer; font: 500 .9rem Inter, sans-serif; min-width: 220px;
}
.search-btn kbd { margin-left: auto; }
.search-btn:hover { color: var(--ink); }
.stats { margin-left: auto; display: flex; gap: 8px; align-items: center; }
.chip {
  display: inline-flex; align-items: center; gap: 6px; white-space: nowrap; text-decoration: none; color: var(--ink);
  background: var(--panel); border: 2px solid var(--line); border-radius: 999px; padding: 4px 11px;
  font: 700 .85rem "Space Grotesk", sans-serif;
}
.chip.hot { background: #ffe6c7; color: #15171e; }
.chip.cold { color: var(--muted); }
.chip.due { background: var(--blue-soft); }
.chip .lvl { background: var(--purple); color: #fff; border-radius: 6px; padding: 0 6px; font-size: .75rem; }
.chip .xpbar { width: 54px; height: 7px; border-radius: 9px; background: var(--soft); overflow: hidden; border: 1.5px solid var(--line); }
.chip .xpbar i { display: block; height: 100%; background: var(--purple); }
.flame { display: inline-block; }
.chip.hot .flame { animation: flicker 1.4s ease-in-out infinite; }
@keyframes flicker { 0%,100% { transform: scale(1) rotate(-3deg); } 50% { transform: scale(1.15) rotate(4deg); } }

/* ───────── drawer ───────── */
#drawer {
  position: fixed; top: 0; left: 0; bottom: 0; width: min(340px, 88vw); z-index: 60;
  background: var(--panel); border-right: 2px solid var(--line); box-shadow: 6px 0 0 var(--shadow);
  transform: translateX(-110%); transition: transform .25s cubic-bezier(.2,.8,.2,1);
  display: flex; flex-direction: column;
}
body.nav-open #drawer { transform: none; }
.drawer-head { display: flex; align-items: center; justify-content: space-between; padding: 12px 14px; border-bottom: 2px solid var(--line); font-family: "Space Grotesk"; font-size: 1.1rem; }
#sidebar { overflow-y: auto; padding: 8px 12px 40px; }
#scrim { position: fixed; inset: 0; background: rgba(10,12,18,.45); z-index: 55; opacity: 0; pointer-events: none; transition: opacity .2s; }
body.nav-open #scrim { opacity: 1; pointer-events: auto; }
nav .sess { margin: 18px 6px 6px; display: flex; justify-content: space-between; align-items: center; }
nav .sess h4 { margin: 0; font-size: .78rem; letter-spacing: .08em; text-transform: uppercase; color: var(--muted); }
nav .sess span { font: 700 .75rem "JetBrains Mono"; color: var(--muted); }
nav a.item {
  display: flex; gap: 10px; align-items: center; color: var(--ink); text-decoration: none;
  padding: 7px 10px; border-radius: 10px; font-size: .92rem; border: 2px solid transparent;
}
nav a.item:hover { background: var(--panel-2); border-color: var(--soft); }
nav a.item.active { background: var(--yellow); color: #15171e; border-color: var(--line); font-weight: 600; }
nav a.item .tick { width: 20px; height: 20px; border-radius: 50%; border: 2px solid var(--line); flex-shrink: 0; display: grid; place-items: center; font-size: 11px; background: var(--panel); color: var(--ink); }
nav a.item.done .tick { background: var(--green); border-color: var(--line); color: #fff; }
nav .tools { display: grid; grid-template-columns: repeat(4, 1fr); gap: 6px; margin: 6px 0; }
nav .tools a { text-align: center; text-decoration: none; padding: 8px 4px; border-radius: 10px; font: 600 .8rem "Space Grotesk"; border: 2px solid var(--line); color: var(--ink); background: var(--panel-2); }
nav .tools a span { display: block; font-size: 1.2rem; }
nav .tools a:hover { box-shadow: var(--sh-sm); }

/* ───────── layout ───────── */
main { max-width: 1120px; margin: 0 auto; padding: 26px clamp(16px, 4vw, 40px) 90px; }
main.narrow { max-width: 860px; }
.view { animation: rise .35s cubic-bezier(.2,.8,.2,1); }
@keyframes rise { from { opacity: 0; transform: translateY(10px); } to { opacity: 1; transform: none; } }

/* buttons */
.btn {
  display: inline-flex; align-items: center; justify-content: center; gap: 6px; text-decoration: none;
  border: 2px solid var(--line); background: var(--panel); color: var(--ink);
  padding: 9px 15px; border-radius: 12px; font: 700 .9rem "Space Grotesk", sans-serif; cursor: pointer;
  box-shadow: var(--sh-sm); transition: transform .08s, box-shadow .08s;
}
.btn:hover { transform: translate(-1px, -1px); box-shadow: 3px 3px 0 var(--shadow); }
.btn:active { transform: translate(2px, 2px); box-shadow: 0 0 0 var(--shadow); }
.btn.primary { background: var(--yellow); color: #15171e; }
.btn.blue { background: var(--blue); color: #fff; }
.btn.ghost { box-shadow: none; background: transparent; }
.btn.big { padding: 13px 22px; font-size: 1.02rem; border-radius: 14px; }
.btn:disabled { opacity: .5; cursor: wait; transform: none; box-shadow: none; }
.row { display: flex; gap: 8px; flex-wrap: wrap; margin-top: 12px; align-items: center; }
.muted { color: var(--muted); }
.small { font-size: .82rem; }
.eyebrow { font: 700 .78rem "Space Grotesk"; letter-spacing: .1em; text-transform: uppercase; color: var(--blue); }

/* cards */
.card { background: var(--panel); border: 2px solid var(--line); border-radius: var(--radius); padding: 20px 22px; margin-bottom: 18px; box-shadow: var(--sh); }
.card h3 { margin: 0 0 10px; font-size: 1.1rem; display: flex; align-items: center; gap: 10px; }
.card p { margin: 0; }
.num { font: 700 .72rem "JetBrains Mono"; background: var(--ink); color: var(--bg); padding: 2px 7px; border-radius: 6px; }

/* ───────── home ───────── */
.home { display: grid; grid-template-columns: minmax(0, 1fr) 340px; gap: 28px; align-items: start; }
.hero {
  position: relative; overflow: hidden; background: var(--yellow); color: #15171e;
  border: 2px solid var(--line); border-radius: 22px; box-shadow: 6px 6px 0 var(--shadow);
  padding: 28px clamp(20px, 4vw, 34px); margin-bottom: 28px;
}
.hero .eyebrow { color: #15171e; opacity: .7; }
.hero h1 { font-size: clamp(2rem, 5vw, 3.1rem); margin: 6px 0 10px; max-width: 14ch; }
.hero p { margin: 0 0 18px; max-width: 46ch; }
.hero .btn { box-shadow: var(--sh-sm); }
.hero .btn.primary { background: #15171e; color: var(--yellow); border-color: #15171e; }
.hero .snake { position: absolute; right: -10px; bottom: -18px; font-size: 140px; transform: rotate(-12deg); opacity: .9; pointer-events: none; }
.hero .term {
  position: absolute; right: 26px; top: 24px; width: 260px; background: var(--code-bg); color: var(--code-ink);
  border: 2px solid #15171e; border-radius: 12px; padding: 10px 12px 12px; font: .8rem/1.5 "JetBrains Mono";
  box-shadow: 4px 4px 0 #15171e; transform: rotate(2deg);
}
.term .dots { display: flex; gap: 5px; margin-bottom: 6px; }
.term .dots i { width: 9px; height: 9px; border-radius: 50%; background: #ff5f57; }
.term .dots i:nth-child(2) { background: #febc2e; } .term .dots i:nth-child(3) { background: #28c840; }
.term .cursor { display: inline-block; width: 7px; height: 1em; background: var(--yellow); vertical-align: -2px; animation: blink 1s steps(1) infinite; }
@keyframes blink { 50% { opacity: 0; } }

/* learning path */
.chapter { margin-bottom: 26px; }
.chapter-head {
  display: flex; align-items: center; gap: 14px; padding: 14px 18px; border: 2px solid var(--line);
  border-radius: 16px; box-shadow: var(--sh); background: var(--panel); position: relative; z-index: 2;
}
.chapter-head .badge { width: 46px; height: 46px; border-radius: 12px; border: 2px solid var(--line); display: grid; place-items: center; font: 700 1.2rem "Space Grotesk"; color: #15171e; flex-shrink: 0; }
.chapter-head h2 { margin: 0; font-size: 1.25rem; }
.chapter-head .meta { margin-left: auto; text-align: right; font-size: .82rem; }
.chapter-head .meta a { font-weight: 600; }
.mini-bar { width: 110px; height: 9px; border: 1.5px solid var(--line); border-radius: 9px; overflow: hidden; background: var(--soft); margin: 4px 0 0 auto; }
.mini-bar i { display: block; height: 100%; background: var(--green); }
.c1 { --c: #ffd43b; } .c2 { --c: #7cc4ff; } .c3 { --c: #ff9fb2; } .c4 { --c: #b9a6ff; } .c5 { --c: #7ee0b5; }
.chapter-head .badge { background: var(--c); }

.trail { position: relative; padding: 40px 0 8px; overflow-x: hidden; overflow-x: clip; } /* hidden first for older iPhones without clip */
.trail svg { position: absolute; inset: 0; width: 100%; height: 100%; pointer-events: none; overflow: visible; }
.trail svg path { fill: none; stroke-width: 5; stroke-linecap: round; }
.trail .t-bg { stroke: var(--soft); stroke-dasharray: 2 12; }
.trail .t-done { stroke: var(--green); }
.stop { position: relative; display: flex; justify-content: center; padding: 10px 0; transform: translateX(calc(var(--x) * min(120px, 9vw))); }
.stop.current { padding-top: 34px; }
.stop a { display: flex; align-items: center; gap: 14px; text-decoration: none; color: var(--ink); position: relative; }
.node {
  width: 62px; height: 62px; border-radius: 50%; border: 2.5px solid var(--line); flex-shrink: 0;
  display: grid; place-items: center; font: 700 1.15rem "Space Grotesk"; background: var(--panel);
  box-shadow: 0 5px 0 var(--shadow); transition: transform .12s, box-shadow .12s; position: relative; z-index: 1;
}
.stop a:hover .node { transform: translateY(-3px); box-shadow: 0 8px 0 var(--shadow); }
.stop a:active .node { transform: translateY(4px); box-shadow: 0 1px 0 var(--shadow); }
.stop.done .node { background: var(--green); color: #fff; }
.stop.current .node { background: var(--c, var(--yellow)); color: #15171e; width: 74px; height: 74px; font-size: 1.5rem; }
.stop.current .node::after {
  content: ""; position: absolute; inset: -9px; border-radius: 50%; border: 3px solid var(--c, var(--yellow));
  animation: ping 1.6s ease-out infinite;
}
@keyframes ping { from { transform: scale(.9); opacity: 1; } to { transform: scale(1.35); opacity: 0; } }
.stop .label { background: var(--panel); border: 2px solid var(--line); border-radius: 12px; padding: 6px 12px; box-shadow: var(--sh-sm); max-width: 230px; line-height: 1.3; font-weight: 600; font-size: .9rem; }
.stop .label small { display: block; font: 500 .72rem "JetBrains Mono"; color: var(--muted); }
.stop.left a { flex-direction: row-reverse; }
.stop.left .label { text-align: right; }
.start-tag {
  position: absolute; top: -34px; left: 50%; transform: translateX(-50%); white-space: nowrap;
  background: var(--ink); color: var(--bg); font: 700 .72rem "Space Grotesk"; letter-spacing: .08em; padding: 3px 9px; border-radius: 8px;
  animation: bob 1.6s ease-in-out infinite;
}
.start-tag::after { content: ""; position: absolute; left: 50%; bottom: -5px; margin-left: -5px; border: 5px solid transparent; border-bottom: 0; border-top-color: var(--ink); }
@keyframes bob { 50% { transform: translate(-50%, -4px); } }

/* side column */
.aside { position: sticky; top: 84px; display: grid; gap: 18px; }
.aside .card { margin: 0; }
.stat-grid { display: grid; grid-template-columns: 1fr 1fr; gap: 12px; }
.stat { border: 2px solid var(--line); border-radius: 14px; padding: 12px 14px; background: var(--panel-2); }
.stat b { display: block; font: 700 1.6rem "Space Grotesk"; line-height: 1.1; }
.stat span { color: var(--muted); font-size: .8rem; }
.week { display: flex; gap: 6px; margin-top: 12px; }
.week div { flex: 1; text-align: center; font: 600 .7rem "JetBrains Mono"; color: var(--muted); }
.week i { display: grid; place-items: center; height: 30px; border-radius: 9px; border: 2px solid var(--line); background: var(--panel); margin-bottom: 3px; font-style: normal; font-size: .9rem; }
.week .on i { background: #ff9f43; }
.week .today i { outline: 3px solid var(--blue); outline-offset: 1px; }
.heat { display: grid; grid-auto-flow: column; grid-template-rows: repeat(7, 11px); gap: 3px; margin-top: 10px; overflow: hidden; }
.heat i { width: 11px; height: 11px; border-radius: 3px; background: var(--soft); }
.heat i.l1 { background: #9be9a8; } .heat i.l2 { background: #40c463; } .heat i.l3 { background: #216e39; }
.daily-card {
  display: flex; align-items: center; gap: 12px; text-decoration: none; color: #15171e;
  background: #7ee0b5; transition: transform .1s, box-shadow .1s;
}
.daily-card:hover { transform: translate(-2px, -2px); box-shadow: 6px 6px 0 var(--shadow); }
.daily-card.done { background: var(--panel); color: var(--ink); }
.daily-card .daily-icon { font-size: 1.8rem; }
.daily-card b { display: block; font: 700 1.05rem "Space Grotesk"; }
.daily-card .small { display: block; line-height: 1.35; opacity: .85; }
.daily-card .go { margin-left: auto; font: 700 .9rem "Space Grotesk"; white-space: nowrap; }
.tip { background: var(--blue-soft); }
.tip h3 { font-size: 1rem; }
.tip p { font-size: .92rem; }
.level-ring { display: flex; align-items: center; gap: 14px; }
.level-ring svg { flex-shrink: 0; }
.level-ring b { font: 700 1.25rem "Space Grotesk"; display: block; }

/* ───────── lesson ───────── */
.crumbs { display: flex; align-items: center; gap: 10px; flex-wrap: wrap; font-size: .85rem; margin-bottom: 10px; }
.crumbs a { color: var(--muted); text-decoration: none; font-weight: 600; }
.crumbs a:hover { color: var(--ink); }
.tag { display: inline-flex; align-items: center; gap: 6px; border: 2px solid var(--line); border-radius: 999px; padding: 1px 10px; font: 700 .75rem "Space Grotesk"; background: var(--c, var(--panel)); color: #15171e; }
.lesson-title { font-size: clamp(1.9rem, 5vw, 2.8rem); margin: 6px 0 6px; }
.mastery { display: flex; align-items: center; gap: 6px; font-size: .8rem; color: var(--muted); margin-bottom: 16px; }
.mastery i { width: 22px; height: 8px; border-radius: 5px; border: 1.5px solid var(--line); background: var(--panel); }
.mastery i.on { background: var(--purple); }

.stepper {
  position: sticky; top: 62px; z-index: 30; display: flex; gap: 6px; overflow-x: auto; scrollbar-width: none;
  padding: 10px 0; margin: 0 0 14px; background: linear-gradient(var(--bg) 75%, transparent);
}
.stepper::-webkit-scrollbar { display: none; }
.stepper button {
  flex-shrink: 0; cursor: pointer; color: var(--muted); border: 2px solid var(--soft); background: var(--panel);
  border-radius: 999px; padding: 4px 12px; font: 700 .8rem "Space Grotesk"; transition: all .15s;
}
.stepper button.seen { color: var(--ink); border-color: var(--line); }
.stepper button.active { background: var(--ink); color: var(--bg); border-color: var(--ink); }

.section { scroll-margin-top: 130px; }
.meaning p { font-size: 1.08rem; line-height: 1.7; }
.trap { background: var(--panel); padding: 0; overflow: hidden; }
.trap .tape {
  background: repeating-linear-gradient(-45deg, var(--yellow) 0 16px, #15171e 16px 32px);
  height: 14px; border-bottom: 2px solid var(--line);
}
.trap .inner { padding: 16px 22px 20px; }
.trap h3 { color: var(--ink); }

/* code */
pre {
  background: var(--code-bg); color: var(--code-ink); padding: 14px 16px; border-radius: 12px; border: 2px solid var(--line);
  overflow-x: auto; margin: 6px 0 0; font-size: .9rem; line-height: 1.6; white-space: pre; tab-size: 4;
}
.tk-kw { color: #c792ea; font-weight: 600; } .tk-str { color: #c3e88d; } .tk-num { color: #f78c6c; }
.tk-com { color: #6e7799; font-style: italic; } .tk-fn { color: #82aaff; } .tk-bi { color: #ffcb6b; } .tk-const { color: #ff9cac; }
.code-head { display: flex; align-items: center; justify-content: space-between; gap: 8px; }

.console {
  margin-top: 12px; background: var(--code-bg); color: var(--code-ink); border: 2px solid var(--line); border-radius: 12px; overflow: hidden;
}
.console .bar-top { display: flex; align-items: center; gap: 8px; padding: 6px 12px; background: #222634; color: #9aa3b8; font: 600 .72rem "JetBrains Mono"; letter-spacing: .05em; }
.console .bar-top .status { margin-left: auto; padding: 1px 8px; border-radius: 6px; }
.console.ok { border-color: var(--green); box-shadow: 0 0 0 3px var(--green-soft); }
.console.ok .status { background: var(--green); color: #fff; }
.console.bad { border-color: var(--red); box-shadow: 0 0 0 3px var(--red-soft); }
.console.bad .status { background: var(--red); color: #fff; }
.console pre { border: 0; border-radius: 0; margin: 0; white-space: pre-wrap; min-height: 52px; }
.console .err { color: #ff8d8f; }
.console .verdict { color: #ffd43b; }

/* editor with live highlighting */
.editor { display: flex; margin-top: 12px; background: var(--code-bg); border: 2px solid var(--line); border-radius: 12px; overflow: hidden; }
.editor:focus-within { box-shadow: 0 0 0 3px var(--yellow); }
.gutter { padding: 14px 8px 14px 12px; text-align: right; color: #4b5268; font: .9rem/1.6 "JetBrains Mono"; user-select: none; border-right: 1px solid var(--code-line); min-width: 40px; white-space: pre; }
.code-area { position: relative; flex: 1; overflow-x: auto; min-width: 0; }
.code-area pre.hl, .code-area textarea {
  margin: 0; padding: 14px 16px; border: 0; border-radius: 0; font: .9rem/1.6 "JetBrains Mono", monospace;
  white-space: pre; tab-size: 4; letter-spacing: 0; word-spacing: 0;
}
.code-area pre.hl { position: absolute; top: 0; left: 0; pointer-events: none; background: transparent; overflow: visible; }
.code-area textarea {
  position: relative; display: block; width: 100%; min-height: 170px; resize: none; overflow: hidden;
  background: transparent; color: transparent; caret-color: var(--yellow); outline: none;
}
.code-area textarea::selection { background: rgba(255, 212, 59, .3); color: transparent; }

/* quiz */
.q + .q { margin-top: 22px; padding-top: 18px; border-top: 2px dashed var(--soft); }
.qtext { font-weight: 600; font-size: 1.02rem; margin: 0 0 4px !important; }
.opts { display: grid; gap: 10px; margin-top: 12px; }
.opt {
  display: flex; align-items: center; gap: 12px; text-align: left; padding: 11px 14px; border-radius: 12px;
  border: 2px solid var(--line); background: var(--panel); color: var(--ink); cursor: pointer;
  font: .92rem "JetBrains Mono", monospace; box-shadow: 0 3px 0 var(--shadow); transition: transform .08s, box-shadow .08s, background .15s;
}
.opt .key { width: 26px; height: 26px; border-radius: 8px; border: 2px solid var(--line); display: grid; place-items: center; font: 700 .78rem "Space Grotesk"; flex-shrink: 0; background: var(--panel-2); }
.opt:hover:not(:disabled) { background: var(--panel-2); transform: translateY(-1px); box-shadow: 0 4px 0 var(--shadow); }
.opt.right { background: var(--green); color: #fff; animation: pop .35s; }
.opt.wrong { background: var(--red); color: #fff; animation: shake .4s; }
.opt.right .key, .opt.wrong .key { background: rgba(255,255,255,.2); border-color: #fff; color: #fff; }
.opt:disabled { cursor: default; }
.opt:disabled:not(.right):not(.wrong) { opacity: .55; }
@keyframes pop { 40% { transform: scale(1.03); } }
@keyframes shake { 20%,60% { transform: translateX(-6px); } 40%,80% { transform: translateX(6px); } }
.why { margin-top: 10px; font-size: .92rem; padding: 0; border-radius: 10px; }
.why:not(:empty) { padding: 10px 14px; border: 2px solid var(--line); }
.why.ok { background: var(--green-soft); } .why.no { background: var(--red-soft); }

.lesson-nav { display: grid; grid-template-columns: 1fr 1fr; gap: 14px; margin-top: 26px; }
.lesson-nav a { text-decoration: none; color: var(--ink); border: 2px solid var(--line); border-radius: 14px; padding: 12px 16px; background: var(--panel); box-shadow: var(--sh-sm); transition: transform .1s, box-shadow .1s; }
.lesson-nav a:hover { transform: translate(-2px, -2px); box-shadow: var(--sh); }
.lesson-nav a small { display: block; color: var(--muted); font: 600 .75rem "Space Grotesk"; text-transform: uppercase; letter-spacing: .08em; }
.lesson-nav a b { font-family: "Space Grotesk"; }
.lesson-nav .next { text-align: right; grid-column: 2; }
.review-banner { background: var(--blue-soft); }

/* ───────── exam ───────── */
.exam-top { display: flex; align-items: center; gap: 12px; flex-wrap: wrap; margin-bottom: 10px; }
.exam-top h1 { font-size: 1.5rem; margin: 0; }
.combo { margin-left: auto; font: 700 1rem "Space Grotesk"; padding: 4px 12px; border: 2px solid var(--line); border-radius: 999px; background: var(--panel); }
.combo.fire { background: #ff9f43; color: #15171e; animation: pop .35s; }
.segs { display: grid; grid-template-columns: repeat(var(--n), 1fr); gap: 5px; margin: 6px 0 22px; }
.segs i { height: 12px; border-radius: 6px; border: 2px solid var(--line); background: var(--panel); }
.segs i.ok { background: var(--green); } .segs i.no { background: var(--red); } .segs i.now { background: var(--yellow); }
.exam-card { padding: 26px; }
.exam-card .from { font-size: .8rem; color: var(--muted); margin-bottom: 8px; }
.result { text-align: center; padding: 30px 22px; }
.result h1 { font-size: clamp(1.8rem, 5vw, 2.6rem); margin: 12px 0 6px; }
.result .missed { text-align: left; max-width: 460px; margin: 18px auto 0; }
.result .missed a { display: flex; justify-content: space-between; padding: 9px 12px; border: 2px solid var(--line); border-radius: 10px; margin-top: 8px; text-decoration: none; color: var(--ink); background: var(--panel-2); }
.result .row { justify-content: center; }
.empty { text-align: center; padding: 40px 22px; }
.empty .big-emoji { font-size: 64px; }

/* ───────── overlays ───────── */
.overlay { position: fixed; inset: 0; z-index: 80; background: rgba(10,12,18,.5); display: flex; align-items: flex-start; justify-content: center; padding: 12vh 16px 16px; animation: fade .15s; overflow-y: auto; overscroll-behavior: contain; }
@keyframes fade { from { opacity: 0; } }
.palette-box { width: min(560px, 100%); background: var(--panel); border: 2px solid var(--line); border-radius: 16px; box-shadow: 6px 6px 0 var(--shadow); overflow: hidden; }
#paletteInput { width: 100%; border: 0; border-bottom: 2px solid var(--line); background: transparent; color: var(--ink); padding: 16px 18px; font: 500 1.05rem Inter; outline: none; }
#paletteList { max-height: 50vh; overflow-y: auto; padding: 6px; }
.p-item { display: flex; align-items: center; gap: 10px; padding: 9px 12px; border-radius: 10px; cursor: pointer; color: var(--ink); text-decoration: none; }
.p-item.sel { background: var(--yellow); color: #15171e; }
.p-item small { margin-left: auto; font: 600 .72rem "JetBrains Mono"; opacity: .7; }
.p-item .dot { width: 10px; height: 10px; border-radius: 50%; border: 2px solid currentColor; flex-shrink: 0; }
.p-item .dot.on { background: var(--green); border-color: var(--green); }
.palette-foot { display: flex; gap: 16px; padding: 8px 14px; border-top: 2px solid var(--soft); font-size: .75rem; color: var(--muted); }
.palette-foot kbd { margin-right: 3px; }

.modal-box { width: min(420px, 100%); margin-top: 6vh; text-align: center; background: var(--panel); border: 2px solid var(--line); border-radius: 22px; box-shadow: 6px 6px 0 var(--shadow); padding: 30px 26px 24px; animation: zoom .35s cubic-bezier(.2,1.4,.4,1); }
@keyframes zoom { from { transform: scale(.8); opacity: 0; } }
.modal-box .big-emoji { font-size: 64px; line-height: 1; }
.modal-box h2 { margin: 12px 0 4px; font-size: 1.7rem; }
.modal-box .gain { display: flex; justify-content: center; gap: 10px; margin: 16px 0 6px; flex-wrap: wrap; }
.modal-box .row { justify-content: center; margin-top: 18px; }

/* ───────── tutor chat ───────── */
.chat-fab {
  position: fixed; right: 20px; bottom: 20px; z-index: 70; display: flex; align-items: center; gap: 8px;
  background: var(--yellow); color: #15171e; border: 2px solid var(--line); border-radius: 999px;
  padding: 11px 18px; font: 700 .95rem "Space Grotesk", sans-serif; cursor: pointer;
  box-shadow: 4px 4px 0 var(--shadow); transition: transform .1s, box-shadow .1s;
}
.chat-fab:hover { transform: translate(-2px, -2px); box-shadow: 6px 6px 0 var(--shadow); }
.chat {
  position: fixed; right: 20px; bottom: 20px; z-index: 75; display: flex; flex-direction: column;
  width: min(410px, calc(100vw - 32px)); height: min(620px, calc(100vh - 100px));
  background: var(--panel); border: 2px solid var(--line); border-radius: 20px; box-shadow: 6px 6px 0 var(--shadow);
  overflow: hidden; animation: zoom .25s cubic-bezier(.2,1.3,.4,1); transform-origin: bottom right;
}
.chat-head { display: flex; align-items: center; gap: 8px; padding: 10px 12px; background: var(--yellow); color: #15171e; border-bottom: 2px solid var(--line); }
.chat-head .icon-btn { width: 34px; height: 34px; background: #fff; color: #15171e; border-color: #15171e; }
.chat-title { flex: 1; min-width: 0; line-height: 1.2; }
.chat-title b { font: 700 1.05rem "Space Grotesk"; display: block; }
.chat-title small { font-size: .75rem; opacity: .75; display: block; white-space: nowrap; overflow: hidden; text-overflow: ellipsis; }
.chat-log { flex: 1; overflow-y: auto; padding: 14px; display: flex; flex-direction: column; gap: 10px; background: var(--bg); }
.msg { max-width: 88%; padding: 9px 13px; border: 2px solid var(--line); border-radius: 14px; font-size: .92rem; line-height: 1.55; overflow-wrap: anywhere; }
.msg.user { align-self: flex-end; background: var(--yellow); color: #15171e; border-bottom-right-radius: 4px; }
.msg.bot { align-self: flex-start; background: var(--panel); border-bottom-left-radius: 4px; }
.msg.err { background: var(--red-soft); }
.msg pre { font-size: .8rem; margin: 8px 0; padding: 10px 12px; }
.msg code { font-size: .85em; background: var(--soft); padding: 1px 5px; border-radius: 5px; }
.msg.user code { background: rgba(0,0,0,.08); }
.typing { display: inline-flex; gap: 4px; margin-left: 4px; vertical-align: middle; }
.typing i { width: 6px; height: 6px; border-radius: 50%; background: var(--muted); animation: dot 1s infinite; }
.typing i:nth-child(2) { animation-delay: .15s; } .typing i:nth-child(3) { animation-delay: .3s; }
@keyframes dot { 0%,100% { opacity: .25; transform: translateY(0); } 50% { opacity: 1; transform: translateY(-3px); } }
.chat-empty { margin: auto 0; text-align: center; color: var(--ink); }
.chat-empty .big { font-size: 44px; }
.chat-empty p { margin: 6px 0 14px; font-size: .92rem; }
.chips { display: flex; flex-wrap: wrap; gap: 8px; justify-content: center; }
.chip-btn { border: 2px solid var(--line); background: var(--panel); color: var(--ink); border-radius: 999px; padding: 6px 12px; font: 600 .82rem Inter, sans-serif; cursor: pointer; box-shadow: var(--sh-sm); }
.chip-btn:hover { background: var(--yellow); color: #15171e; }
.chat-form { display: flex; gap: 8px; align-items: flex-end; padding: 10px 12px 4px; border-top: 2px solid var(--line); }
.chat-form textarea {
  flex: 1; resize: none; border: 2px solid var(--line); border-radius: 12px; padding: 9px 12px; max-height: 140px;
  font: .95rem/1.4 Inter, sans-serif; background: var(--panel-2); color: var(--ink); outline: none;
}
.chat-form textarea:focus { box-shadow: 0 0 0 3px var(--yellow); }
.chat-form .btn { padding: 9px 14px; }
.chat-note { margin: 0; padding: 2px 12px 8px; font-size: .7rem; color: var(--muted); text-align: center; }
@media (max-width: 700px) {
  .chat { right: 0; bottom: 0; width: 100vw; height: 88vh; border-radius: 20px 20px 0 0; box-shadow: none; }
  .chat-fab { right: 14px; bottom: 14px; padding: 10px 14px; }
}

/* ───────── name prompt ───────── */
.name-box input {
  width: 100%; margin-top: 14px; padding: 12px 14px; border: 2px solid var(--line); border-radius: 12px;
  font: 600 1.05rem Inter, sans-serif; background: var(--panel-2); color: var(--ink); outline: none; text-align: center;
}
.name-box input:focus { box-shadow: 0 0 0 3px var(--yellow); }
.name-box .privacy { margin: 12px 0 0; line-height: 1.45; }
.who {
  display: flex; align-items: center; gap: 6px; width: 100%; margin: 4px 0 8px; padding: 8px 10px;
  border: 2px dashed var(--soft); border-radius: 10px; background: transparent; color: var(--ink);
  font: 600 .88rem Inter, sans-serif; cursor: pointer; text-align: left;
}
.who span { margin-left: auto; font-size: .75rem; color: var(--muted); }
.who:hover { border-color: var(--line); }

#confetti { position: fixed; inset: 0; width: 100%; height: 100%; pointer-events: none; z-index: 90; }

#toast {
  position: fixed; bottom: 22px; left: 50%; transform: translateX(-50%) translateY(140px);
  background: var(--ink); color: var(--bg); padding: 11px 18px; border-radius: 12px; font: 600 .92rem Inter;
  border: 2px solid var(--line); box-shadow: 4px 4px 0 var(--yellow);
  transition: transform .3s cubic-bezier(.2,1.3,.4,1), opacity .25s; z-index: 95; max-width: 90vw; opacity: 0; pointer-events: none;
}
#toast.show { transform: translateX(-50%) translateY(0); opacity: 1; }

/* ───────── responsive ───────── */
@media (max-width: 980px) {
  .home { grid-template-columns: 1fr; }
  .aside { position: static; }
  .hero .term { display: none; }
}
@media (max-width: 700px) {
  .search-btn { min-width: 0; margin-left: 0; padding: 0; width: 40px; height: 40px; justify-content: center; }
  .search-btn .search-label, .search-btn kbd { display: none; }
  .stats .hide-sm { display: none; }
  .brand-word { display: none; }
  .stop { transform: translateX(calc(var(--x) * 36px)); }
  .stop .label { max-width: 170px; }
  .stepper { top: 60px; }
  .card { padding: 16px; }
  .lesson-nav { grid-template-columns: 1fr; }
  .lesson-nav .next { grid-column: 1; }
  .hero .snake { font-size: 96px; opacity: .35; }
  .overlay { padding: 16px 12px; }
  .modal-box { margin: auto 0; padding: 22px 18px 18px; }
  .modal-box .big-emoji { font-size: 48px; }
}
@media (prefers-reduced-motion: reduce) {
  *, *::before, *::after { animation: none !important; transition: none !important; }
}