/* Kaina student cabinet. Visual language of the landing site/index.html (palette of its
   final "Astra" layer, the one the page renders): ink #20211d, paper #f5f3eb, lime #D4FF00 markers, mono chips, rounded cards,
   lime CTA with ink border and 3px ink shadow. Mobile first (390 px), desktop 1280. */
:root{
  color-scheme:light;
  --bg:#f5f3eb; --bg-2:#eeeee4; --beige:#eeeee3; --beige-2:#e2e1d4;
  --card:#fffef9; --ink:#20211d; --ink-2:#626359; --ink-3:#7c7d71;
  --line:#d8d8cc; --line-2:#c9cabd; --chip-line:#a1a295;
  --lime:#D4FF00; --lime-hover:#BFEA00; --lime-wash:rgba(212,255,0,.14);
  --err:#B42318; --err-wash:#FEF3F2;
  --mono:"IBM Plex Mono",ui-monospace,Menlo,monospace;
  --sans:"Inter",ui-sans-serif,system-ui,-apple-system,"Segoe UI",Arial,sans-serif;
  --r-md:6px; --r-lg:9px; --r-xl:12px;
}
*{box-sizing:border-box;margin:0;padding:0}
html{-webkit-text-size-adjust:100%;background:var(--bg)}
body{background-color:var(--bg);color:var(--ink);font-family:var(--sans);font-size:16px;line-height:1.5;-webkit-font-smoothing:antialiased;overflow-x:hidden;min-height:100vh}
h1,h2,h3,h4{font-weight:500;letter-spacing:-.045em;line-height:1.1;color:var(--ink)}
p{color:var(--ink-2)}
a{color:inherit;text-decoration:none}
button{font:inherit;color:inherit;background:none;border:0;cursor:pointer}
input{font:inherit}
img{display:block;max-width:100%}
[hidden]{display:none!important}
:focus-visible{outline:2px solid var(--ink);outline-offset:3px}
h1:focus{outline:none}
.sprite{position:absolute;width:0;height:0;overflow:hidden}
svg.i{width:18px;height:18px;flex:none}

/* primitives */
.btn{display:inline-flex;align-items:center;justify-content:center;gap:10px;min-height:46px;padding:12px 18px;border:1px solid var(--ink);border-radius:var(--r-md);background:var(--ink);color:var(--bg);font:600 15px/1.3 var(--sans);letter-spacing:-.01em;white-space:nowrap;cursor:pointer;transition:background .15s,transform .15s,box-shadow .15s,opacity .15s}
.btn.cta{background:var(--lime);color:var(--ink);box-shadow:0 3px 0 var(--ink)}
.btn.cta:active:not(:disabled){transform:translateY(2px);box-shadow:0 1px 0 var(--ink)}
.btn.ghost{background:transparent;color:var(--ink);border-color:var(--chip-line)}
.btn.sm{min-height:38px;padding:8px 14px;font-size:14px}
.btn.full{display:flex;width:100%}
.btn:disabled{opacity:.4;cursor:not-allowed}
.btn[aria-busy="true"]{opacity:.7;cursor:progress}
@media (hover:hover){
  .btn:hover:not(:disabled){background:#3e4037}
  .btn.cta:hover:not(:disabled){background:var(--lime-hover);transform:translateY(-1px);box-shadow:0 4px 0 var(--ink)}
  .btn.ghost:hover:not(:disabled){background:var(--beige)}
}
.card{background:var(--card);border:1px solid var(--line-2);border-radius:var(--r-lg)}
.eyebrow{display:inline-flex;align-items:center;gap:10px;font-family:var(--mono);font-size:11px;text-transform:uppercase;letter-spacing:.095em;color:var(--ink)}
.eyebrow::before{content:"";width:7px;height:7px;background:var(--lime);border:1px solid var(--ink);flex:none}
.chip{display:inline-flex;align-items:center;gap:6px;white-space:nowrap;border:1px solid var(--chip-line);border-radius:30px;padding:4px 10px;font-family:var(--mono);font-size:10.5px;text-transform:uppercase;letter-spacing:.05em;color:var(--ink);background:transparent}
.chip.ink{background:var(--ink);border-color:var(--ink);color:var(--bg)}
.chip.lime{background:var(--lime);border-color:var(--ink)}
.chip svg.i{width:12px;height:12px}
.prog{height:10px;background:var(--bg-2);border:1px solid var(--line-2);border-radius:999px;overflow:hidden}
.prog i{display:block;height:100%;background:var(--lime);border-right:1px solid var(--ink);transition:width .3s}
.link{display:inline-block;margin-top:18px;font-size:15px;font-weight:500;text-decoration:underline;text-decoration-color:var(--chip-line);text-underline-offset:3px}
.link:hover{text-decoration-color:var(--ink)}
.note{margin-top:16px;padding:12px 14px;border-radius:var(--r-md);font-size:15px;color:var(--ink);border:1px solid var(--line-2);background:var(--bg-2)}
.note.ok{border-color:var(--ink);background:var(--lime-wash)}
.note.warn{background:var(--beige)}
.form-err{margin-top:16px;padding:10px 12px;border-radius:var(--r-md);background:var(--err-wash);border:1px solid #F4C7C3;color:var(--err);font-size:14.5px}
.demo-strip{display:flex;align-items:center;justify-content:center;gap:8px;padding:7px 16px;background:var(--beige);border-bottom:1px solid var(--line-2);font-family:var(--mono);font-size:10.5px;letter-spacing:.05em;text-transform:uppercase;color:var(--ink-2);text-align:center}
.demo-strip i{width:6px;height:6px;background:var(--lime);border:1px solid var(--ink);flex:none}
.boot{padding:80px 20px;text-align:center;font-family:var(--mono);font-size:12px;text-transform:uppercase;letter-spacing:.08em;color:var(--ink-2)}

/* forms */
.field{display:grid;gap:6px;margin-top:18px}
.field label{font-size:14px;font-weight:600}
.field input{width:100%;height:52px;border:1px solid var(--line-2);border-radius:var(--r-md);background:var(--card);padding:0 14px;font-size:17px;color:var(--ink)}
.field input:focus{outline:none;border-color:var(--ink);box-shadow:0 0 0 1px var(--ink)}
.field input[aria-invalid="true"]{border-color:var(--err);box-shadow:0 0 0 1px var(--err)}
.field small{font-size:13px;color:var(--ink-2)}
form .btn{margin-top:22px}

/* auth screens */
.auth{display:flex;flex-direction:column;align-items:center;padding:32px 16px 48px}
.auth-logo img{height:30px;width:auto}
.auth-card{width:100%;max-width:440px;margin-top:28px;padding:24px 20px}
.auth-card h1{font-size:32px;margin-top:14px}
.auth-card .lead{font-size:15.5px;margin-top:10px}
.auth-links{display:flex;flex-wrap:wrap;justify-content:space-between;column-gap:18px}
.field input.code-input{font-family:var(--mono);font-size:24px;letter-spacing:.4em;text-align:center}
.code-actions{display:flex;flex-wrap:wrap;justify-content:space-between;column-gap:18px}
button.link{text-align:left}
button.link:disabled{color:var(--ink-3);text-decoration:none;cursor:default}
@media (min-width:600px){.auth{padding-top:72px}.auth-card{padding:32px}.auth-card h1{font-size:38px}}

/* app header */
.wrap{max-width:820px;margin:0 auto;padding:0 16px}
.top{position:sticky;top:0;z-index:10;background:rgba(245,243,235,.94);-webkit-backdrop-filter:blur(8px);backdrop-filter:blur(8px);border-bottom:1px solid var(--line)}
.top-in{display:flex;align-items:center;justify-content:space-between;gap:12px;height:64px;max-width:1120px}
.brand{min-width:0;flex:0 1 auto}
.brand-logo{height:24px;width:auto}
.who{display:flex;align-items:center;gap:12px;min-width:0}
.who-txt{display:block;min-width:0;max-width:110px;text-align:right;line-height:1.25}
.who-txt b{display:block;font-size:14px;font-weight:600;overflow:hidden;text-overflow:ellipsis;white-space:nowrap}
.who-txt span{display:none;font-size:12.5px;color:var(--ink-2);overflow:hidden;text-overflow:ellipsis;white-space:nowrap;max-width:240px}
@media (min-width:600px){.who-txt{max-width:none}.who-txt span{display:block}.brand-logo{height:30px}.top-in{height:72px;padding:0 24px}}

/* lessons list */
.page{padding:28px 16px 64px}
.page-h h1{font-size:34px;margin-top:12px}
@media (min-width:900px){.page{padding:48px 24px 88px}.page-h h1{font-size:48px}}
.progress-card{margin-top:20px;padding:16px 18px}
.progress-row{display:flex;align-items:center;justify-content:space-between;gap:12px;margin-bottom:12px}
.progress-row b{font-size:16px;font-weight:600}
.lessons{list-style:none;display:grid;gap:10px;margin-top:20px}
.lesson{display:flex;gap:14px;align-items:flex-start;padding:16px;background:var(--card);border:1px solid var(--line-2);border-radius:var(--r-lg);position:relative}
a.lesson{transition:border-color .15s,background .15s}
@media (hover:hover){a.lesson:hover{border-color:var(--ink)}}
.lesson .n{width:38px;height:38px;border-radius:50%;flex:none;display:grid;place-items:center;font-size:15px;font-weight:600;border:1.5px solid var(--line-2);background:var(--card);color:var(--ink-2)}
.lesson .n svg.i{width:18px;height:18px}
.lesson-main{min-width:0;flex:1}
.lesson-main b{display:block;margin-top:8px;font-size:17px;font-weight:600;letter-spacing:-.02em;line-height:1.3;color:var(--ink)}
.lesson-main .sub{display:block;margin-top:3px;font-size:14px;line-height:1.4;color:var(--ink-2)}
.lesson-top{display:flex;align-items:center;justify-content:space-between;gap:8px;flex-wrap:wrap}
.st{display:inline-flex;align-items:center;gap:5px;font-family:var(--mono);font-size:10.5px;text-transform:uppercase;letter-spacing:.05em;color:var(--ink-2);white-space:nowrap}
.st svg.i{width:13px;height:13px}
.lesson.is-done .n{background:var(--ink);border-color:var(--ink);color:var(--lime)}
.lesson.is-done .st{color:var(--ink)}
.lesson.is-locked{background:var(--bg-2);border-style:dashed}
.lesson.is-locked b{color:var(--ink-2);font-weight:500}
.lesson.is-current{border:1.5px solid var(--ink);background:linear-gradient(var(--lime-wash),var(--lime-wash)),var(--card);box-shadow:0 3px 0 var(--ink);flex-wrap:wrap}
.lesson.is-current .n{background:var(--lime);border-color:var(--ink);color:var(--ink)}
.lesson.is-current .btn{margin-top:14px}
.lesson-go{width:100%;padding-left:52px}
@media (min-width:600px){.lesson{padding:18px 20px;gap:16px}.lesson-main b{font-size:18px}.lesson.is-current{flex-wrap:nowrap;align-items:center}.lesson-go{width:auto;padding-left:0}.lesson.is-current .btn{margin-top:0}}
@media (max-width:599px){.lesson-go .btn{width:100%}}

/* lesson page */
.back{display:inline-flex;align-items:center;gap:8px;font-size:14.5px;font-weight:500;color:var(--ink-2)}
.back:hover{color:var(--ink)}
.lesson-h{display:flex;gap:8px;flex-wrap:wrap;margin-top:22px}
.lesson-page h1{font-size:32px;margin-top:14px;text-wrap:balance}
.lesson-sub{font-size:17px;margin-top:10px}
@media (min-width:900px){.lesson-page h1{font-size:46px}.lesson-sub{font-size:19px}}
.video{margin-top:22px;border-radius:var(--r-xl);overflow:hidden;border:1px solid var(--line-2);background:var(--ink);aspect-ratio:16/9}
.video iframe{display:block;width:100%;height:100%;border:0}
.video.empty{display:grid;place-items:center;align-content:center;gap:12px;background:var(--beige);background-image:radial-gradient(#C9CABD .8px,transparent .8px);background-size:16px 16px;text-align:center;padding:16px}
.video.empty .play{width:56px;height:56px;border-radius:50%;display:grid;place-items:center;background:var(--card);border:1px solid var(--chip-line);color:var(--ink-2)}
.video.empty .play svg{width:22px;height:22px;margin-left:3px}
.video.empty b{font-size:16px;font-weight:600}
.video.empty span{font-size:14px;color:var(--ink-2)}
.lesson-body{margin-top:16px;padding:20px 18px;font-size:16.5px;line-height:1.6;color:var(--ink);overflow-wrap:anywhere}
.lesson-body>*+*{margin-top:14px}
.lesson-body p{color:var(--ink)}
.lesson-body h2{font-size:24px;margin-top:26px}
.lesson-body h3{font-size:20px;margin-top:22px}
.lesson-body h4{font-size:17px;margin-top:18px}
.lesson-body :is(h2,h3,h4):first-child{margin-top:0}
.lesson-body ul,.lesson-body ol{padding-left:22px}
.lesson-body li+li{margin-top:6px}
.lesson-body ul li::marker{color:var(--ink-3)}
.lesson-body strong{font-weight:600}
.lesson-body a{text-decoration:underline;text-decoration-color:var(--lime-hover);text-decoration-thickness:2px;text-underline-offset:3px}
.lesson-body a:hover{text-decoration-color:var(--ink)}
.lesson-body .empty-text{color:var(--ink-2)}
@media (min-width:900px){.lesson-body{padding:28px 32px}}
.lesson-actions{margin-top:22px}
.lesson-actions .btn{width:100%}
.lesson-nav{display:flex;flex-wrap:wrap;gap:10px;justify-content:space-between;margin-top:18px;padding-top:18px;border-top:1px solid var(--line)}
.lesson-nav .btn{flex:1 1 150px}
.next-hint{flex-basis:100%;font-size:13px;color:var(--ink-2);text-align:right}
@media (min-width:600px){.lesson-actions .btn{width:auto}.lesson-nav .btn{flex:0 0 auto}}
@media (prefers-reduced-motion:reduce){*{transition:none!important}}