/* StudyHub — ultramar sobre papel frío, con subrayador amarillo como firma */
:root {
  --bg: #f1f2f8; --surface: #ffffff; --surface2: #e9ebf5; --text: #0e1020; --muted: #62677f;
  --border: rgba(14, 16, 32, .09); --border-strong: rgba(14, 16, 32, .16);
  --primary: #4f46ff; --primary-d: #3a31e0; --primary-soft: #e8e7ff; --on-primary: #fff;
  --mark: #ffe15a; --mark-solid: #ffe15a; --ink: #0e1020;
  --ok: #0c9f64; --ok-soft: #e0f6ec; --bad: #e03e45; --bad-soft: #fde8e9; --warn: #c67600; --warn-soft: #fff1d6;
  --glass: rgba(255, 255, 255, .72);
  --shadow: 0 1px 1px rgba(14, 16, 32, .04), 0 10px 28px -12px rgba(40, 34, 140, .16);
  --shadow-lg: 0 2px 4px rgba(14, 16, 32, .05), 0 24px 56px -18px rgba(40, 34, 140, .32);
  --r-xl: 28px; --r: 20px; --r-sm: 12px;
  --font-display: "Bricolage Grotesque", "Avenir Next", "Segoe UI", system-ui, sans-serif;
  --font: "Geist", -apple-system, BlinkMacSystemFont, "Segoe UI", system-ui, sans-serif;
  color-scheme: light;
}
@media (prefers-color-scheme: dark) {
  :root:not([data-theme="light"]) {
    --bg: #080a14; --surface: #12152a; --surface2: #1b1f3a; --text: #eef0ff; --muted: #8e93b3;
    --border: rgba(255, 255, 255, .08); --border-strong: rgba(255, 255, 255, .16);
    --primary: #7d7cff; --primary-d: #9a99ff; --primary-soft: rgba(125, 124, 255, .16); --on-primary: #0b0c1c;
    --mark: rgba(255, 214, 10, .42);
    --ok: #3ddc97; --ok-soft: rgba(61, 220, 151, .13); --bad: #ff7b81; --bad-soft: rgba(255, 123, 129, .13); --warn: #ffc247; --warn-soft: rgba(255, 194, 71, .13);
    --glass: rgba(18, 21, 42, .72);
    --shadow: 0 1px 1px rgba(0, 0, 0, .3), 0 10px 28px -12px rgba(0, 0, 0, .6);
    --shadow-lg: 0 2px 4px rgba(0, 0, 0, .4), 0 24px 56px -18px rgba(0, 0, 0, .8);
    color-scheme: dark;
  }
}
:root[data-theme="dark"] {
  --bg: #080a14; --surface: #12152a; --surface2: #1b1f3a; --text: #eef0ff; --muted: #8e93b3;
  --border: rgba(255, 255, 255, .08); --border-strong: rgba(255, 255, 255, .16);
  --primary: #7d7cff; --primary-d: #9a99ff; --primary-soft: rgba(125, 124, 255, .16); --on-primary: #0b0c1c;
  --mark: rgba(255, 214, 10, .42);
  --ok: #3ddc97; --ok-soft: rgba(61, 220, 151, .13); --bad: #ff7b81; --bad-soft: rgba(255, 123, 129, .13); --warn: #ffc247; --warn-soft: rgba(255, 194, 71, .13);
  --glass: rgba(18, 21, 42, .72);
  --shadow: 0 1px 1px rgba(0, 0, 0, .3), 0 10px 28px -12px rgba(0, 0, 0, .6);
  --shadow-lg: 0 2px 4px rgba(0, 0, 0, .4), 0 24px 56px -18px rgba(0, 0, 0, .8);
  color-scheme: dark;
}

* { box-sizing: border-box; }
html { -webkit-text-size-adjust: 100%; scroll-behavior: smooth; }
body {
  margin: 0; color: var(--text); font: 15.5px/1.55 var(--font); letter-spacing: -.005em;
  background:
    radial-gradient(900px 520px at 8% -8%, color-mix(in srgb, var(--primary) 13%, transparent), transparent 70%),
    radial-gradient(700px 480px at 100% 0%, color-mix(in srgb, var(--mark) 22%, transparent), transparent 70%),
    var(--bg);
  background-attachment: fixed;
  padding-bottom: env(safe-area-inset-bottom);
  -webkit-font-smoothing: antialiased;
}
h1, h2, h3 { font-family: var(--font-display); line-height: 1.12; margin: 0 0 .5em; letter-spacing: -.02em; font-weight: 700; }
h1 { font-size: clamp(1.7rem, 3.2vw, 2.4rem); font-weight: 800; }
h2 { font-size: 1.35rem; } h3 { font-size: 1.05rem; font-weight: 650; }
a { color: var(--primary-d); text-underline-offset: 3px; }
button, input, select, textarea { font: inherit; color: inherit; letter-spacing: inherit; }
:focus-visible { outline: 2px solid var(--primary); outline-offset: 2px; border-radius: 8px; }
.muted { color: var(--muted); } .small { font-size: .85rem; } .center { text-align: center; }
.row { display: flex; gap: .6rem; align-items: center; flex-wrap: wrap; }
.row.between { justify-content: space-between; } .grow { flex: 1; min-width: 0; }
.stack > * + * { margin-top: 1rem; }
.hidden { display: none !important; }
.ic { width: 1.2em; height: 1.2em; flex: none; stroke: currentColor; fill: none; stroke-width: 1.9; stroke-linecap: round; stroke-linejoin: round; }

/* la firma: subrayador */
.mark {
  background: linear-gradient(transparent 56%, var(--mark) 56% 90%, transparent 90%);
  padding: 0 .12em; margin: 0 -.12em; border-radius: 2px;
}

/* ───── estructura ───── */
.shell { display: grid; grid-template-columns: 252px minmax(0, 1fr); min-height: 100vh; }
.side {
  position: sticky; top: 14px; height: calc(100vh - 28px); margin: 14px 0 14px 14px; padding: 1rem .8rem;
  display: flex; flex-direction: column; gap: .3rem; overflow-y: auto;
  background: var(--glass); border: 1px solid var(--border); border-radius: 26px; box-shadow: var(--shadow);
  -webkit-backdrop-filter: blur(22px) saturate(1.4); backdrop-filter: blur(22px) saturate(1.4);
}
.brand { display: flex; align-items: center; gap: .65rem; padding: .35rem .6rem 1.1rem; font: 800 1.25rem var(--font-display); letter-spacing: -.03em; color: var(--text); text-decoration: none; }
.logo-mark {
  width: 34px; height: 34px; border-radius: 11px; display: grid; place-items: center; color: #fff;
  background: linear-gradient(140deg, #6a63ff, #3a31e0); box-shadow: 0 6px 16px -6px rgba(79, 70, 255, .7), inset 0 1px 0 rgba(255, 255, 255, .35);
}
.logo-mark svg { width: 19px; height: 19px; stroke: currentColor; fill: none; stroke-width: 2.2; stroke-linecap: round; stroke-linejoin: round; }
.nav { display: flex; flex-direction: column; gap: 2px; }
.nav a {
  display: flex; align-items: center; gap: .75rem; padding: .62rem .8rem; border-radius: 13px; color: var(--muted);
  text-decoration: none; font-weight: 550; transition: background .15s, color .15s;
}
.nav a:hover { background: var(--surface2); color: var(--text); }
.nav a.active { background: var(--primary-soft); color: var(--primary-d); font-weight: 650; }
.nav .badge { margin-left: auto; }
.side .spacer { flex: 1; }
.me {
  display: flex; align-items: center; gap: .65rem; padding: .55rem; border-radius: 16px; text-decoration: none; color: var(--text);
  border: 1px solid var(--border); background: var(--surface);
}
.me:hover, .me.active { border-color: var(--primary); }
.me .grow { display: flex; flex-direction: column; line-height: 1.25; }
.me .ic { color: var(--muted); }
.avatar {
  width: 36px; height: 36px; border-radius: 12px; display: grid; place-items: center; flex: none; font: 800 1rem var(--font-display);
  background: var(--mark-solid); color: var(--ink);
}
.main { padding: 1.8rem clamp(1rem, 3.2vw, 3rem) 5rem; max-width: 1180px; width: 100%; position: relative; }
.mobile-me { display: none; }
.tabbar { display: none; }
.page-head { margin-bottom: 1.3rem; }
.page-head p { margin: 0; }

@media (max-width: 900px) {
  .shell { grid-template-columns: 1fr; }
  .side { display: none; }
  .main { padding: 1.1rem 1rem 7rem; }
  .mobile-me { display: block; position: absolute; top: 1.1rem; right: 1rem; z-index: 5; }
  .page-head, .main > h1:first-child { padding-right: 3rem; }
  .tabbar {
    display: flex; position: fixed; left: 12px; right: 12px; bottom: calc(12px + env(safe-area-inset-bottom)); z-index: 30; padding: .35rem;
    background: var(--glass); border: 1px solid var(--border); border-radius: 26px; box-shadow: var(--shadow-lg);
    -webkit-backdrop-filter: blur(22px) saturate(1.4); backdrop-filter: blur(22px) saturate(1.4);
  }
  .tabbar a {
    flex: 1; display: flex; flex-direction: column; align-items: center; gap: 2px; padding: .5rem 0 .4rem; border-radius: 20px;
    text-decoration: none; color: var(--muted); font-size: .68rem; font-weight: 600; position: relative;
  }
  .tabbar a .ic { width: 22px; height: 22px; }
  .tabbar a.active { color: var(--primary-d); background: var(--primary-soft); }
  .tabbar .badge { position: absolute; top: 2px; left: calc(50% + 6px); }
}

/* ───── componentes base ───── */
.card {
  background: var(--surface); border: 1px solid var(--border); border-radius: var(--r); padding: 1.15rem; box-shadow: var(--shadow);
}
.card.click { cursor: pointer; transition: transform .16s, box-shadow .16s, border-color .16s; }
.card.click:hover { transform: translateY(-2px); border-color: color-mix(in srgb, var(--primary) 55%, transparent); box-shadow: var(--shadow-lg); }
.grid { display: grid; gap: 1rem; grid-template-columns: repeat(auto-fill, minmax(255px, 1fr)); }
.grid.two { grid-template-columns: repeat(auto-fit, minmax(310px, 1fr)); }
.btn {
  display: inline-flex; align-items: center; justify-content: center; gap: .45rem; padding: .6rem 1.05rem; border-radius: var(--r-sm);
  border: 1px solid var(--border-strong); background: var(--surface); cursor: pointer; font-weight: 600; text-decoration: none; color: var(--text);
  transition: transform .1s, background .15s, border-color .15s, box-shadow .15s;
}
.btn:hover { background: var(--surface2); }
.btn:active { transform: scale(.98); }
.btn.primary {
  background: var(--primary); border-color: transparent; color: var(--on-primary);
  box-shadow: 0 8px 20px -8px color-mix(in srgb, var(--primary) 80%, transparent), inset 0 1px 0 rgba(255, 255, 255, .22);
}
.btn.primary:hover { background: var(--primary-d); }
.btn.danger { color: var(--bad); }
.btn.ghost { border-color: transparent; background: transparent; }
.btn.ghost:hover { background: var(--surface2); }
.btn.sm { padding: .32rem .7rem; font-size: .85rem; border-radius: 10px; }
.btn[disabled] { opacity: .55; cursor: not-allowed; }
.badge { background: var(--primary); color: var(--on-primary); border-radius: 999px; font-size: .72rem; padding: .05rem .5rem; font-weight: 700; min-width: 1.4rem; text-align: center; }
.badge.soft { background: var(--primary-soft); color: var(--primary-d); }
.pill { display: inline-block; padding: .12rem .6rem; border-radius: 999px; font-size: .78rem; font-weight: 550; background: var(--surface2); color: var(--muted); white-space: nowrap; }
label.f { display: block; font-size: .83rem; color: var(--muted); margin-bottom: .25rem; font-weight: 600; }
input[type=text], input[type=email], input[type=password], input[type=date], input[type=number], input[type=search], select, textarea {
  width: 100%; padding: .66rem .85rem; border: 1px solid var(--border-strong); border-radius: var(--r-sm); background: var(--surface); outline: none;
  transition: border-color .15s, box-shadow .15s;
}
input:focus, select:focus, textarea:focus { border-color: var(--primary); box-shadow: 0 0 0 4px var(--primary-soft); }
textarea { resize: vertical; min-height: 140px; }
textarea.big { min-height: 55vh; font-family: ui-monospace, "SF Mono", Menlo, monospace; font-size: .9rem; line-height: 1.6; }
input[type=color] { width: 46px; height: 40px; border: 1px solid var(--border-strong); border-radius: 10px; padding: 3px; background: var(--surface); }
input[type=checkbox] { accent-color: var(--primary); }
.bar { height: 8px; border-radius: 99px; background: var(--surface2); overflow: hidden; }
.bar > i { display: block; height: 100%; background: var(--primary); border-radius: 99px; transition: width .5s cubic-bezier(.2, .8, .2, 1); }

/* pestañas: control segmentado */
.tabs {
  display: inline-flex; gap: 3px; padding: 4px; margin: 1.1rem 0; max-width: 100%; overflow-x: auto;
  background: var(--surface2); border-radius: 16px; border: 1px solid var(--border);
}
.tabs button {
  background: none; border: 0; padding: .5rem .95rem; cursor: pointer; color: var(--muted); font-weight: 600; white-space: nowrap; border-radius: 12px;
  transition: background .15s, color .15s;
}
.tabs button:hover { color: var(--text); }
.tabs button.active { background: var(--surface); color: var(--text); box-shadow: var(--shadow); }
.seg { display: grid; grid-auto-flow: column; grid-auto-columns: 1fr; gap: 3px; padding: 4px; background: var(--surface2); border-radius: 15px; border: 1px solid var(--border); }
.seg button { border: 0; background: none; padding: .55rem; border-radius: 11px; font-weight: 650; color: var(--muted); cursor: pointer; }
.seg button.active { background: var(--surface); color: var(--text); box-shadow: var(--shadow); }

.stat { text-align: center; } .stat b { display: block; font: 800 1.9rem var(--font-display); line-height: 1.1; letter-spacing: -.03em; } .stat span { color: var(--muted); font-size: .82rem; }
.list > * { border-bottom: 1px solid var(--border); } .list > *:last-child { border-bottom: 0; }
.item { padding: .8rem .2rem; display: flex; gap: .75rem; align-items: center; }
.empty { text-align: center; color: var(--muted); padding: 2.4rem 1rem; }
.empty .big { font-size: 2.6rem; margin-bottom: .3rem; }
.chip-emoji { font-size: 1.7rem; line-height: 1; }
.spinner { width: 18px; height: 18px; border: 3px solid var(--border-strong); border-top-color: var(--primary); border-radius: 50%; animation: spin .7s linear infinite; display: inline-block; vertical-align: -3px; }
.btn.primary .spinner { border-color: rgba(255, 255, 255, .35); border-top-color: #fff; }
@keyframes spin { to { transform: rotate(360deg); } }

/* ───── inicio: bento ───── */
.bento { display: grid; gap: 1rem; grid-template-columns: repeat(12, minmax(0, 1fr)); grid-auto-flow: dense; }
.tile { background: var(--surface); border: 1px solid var(--border); border-radius: var(--r); padding: 1.15rem 1.25rem; box-shadow: var(--shadow); min-width: 0; }
.tile-label { font-size: .85rem; font-weight: 650; color: var(--muted); margin-bottom: .6rem; display: flex; align-items: center; gap: .4rem; }
.tile.hero {
  grid-column: span 6; grid-row: span 2; border: 0; border-radius: var(--r-xl); padding: 1.8rem; color: #fff; position: relative; overflow: hidden;
  display: flex; flex-direction: column; justify-content: flex-end; min-height: 300px;
  background:
    radial-gradient(520px 340px at 100% 0%, rgba(255, 150, 214, .5), transparent 62%),
    radial-gradient(420px 360px at 0% 110%, rgba(130, 110, 255, .7), transparent 65%),
    linear-gradient(150deg, #5a52ff 0%, #3326d4 100%);
  box-shadow: var(--shadow-lg);
}
.tile.hero::after {
  content: ""; position: absolute; top: -34px; right: -34px; width: 230px; height: 230px; opacity: .16; pointer-events: none; transform: rotate(-12deg);
  background: url("data:image/svg+xml,%3Csvg xmlns='http://www.w3.org/2000/svg' viewBox='0 0 24 24' fill='none' stroke='white' stroke-width='1.1' stroke-linecap='round' stroke-linejoin='round'%3E%3Cpath d='m12 3 9 5-9 5-9-5z'/%3E%3Cpath d='m3 13 9 5 9-5'/%3E%3Cpath d='m3 17.5 9 5 9-5' opacity='.55'/%3E%3C/svg%3E") center / contain no-repeat;
}
.hero-label { font-weight: 650; opacity: .9; }
.hero-num { font: 800 clamp(4.5rem, 10vw, 7.5rem)/.9 var(--font-display); letter-spacing: -.06em; margin: .25rem 0 .2rem; }
.hero-num .ic { width: 1em; height: 1em; stroke-width: 2.2; }
.hero-sub { opacity: .88; margin-bottom: 1.3rem; }
.btn.cta { background: var(--mark-solid); color: var(--ink); border: 0; align-self: flex-start; padding: .8rem 1.3rem; font-weight: 700; font-size: 1.02rem; border-radius: 15px; box-shadow: 0 10px 24px -10px rgba(0, 0, 0, .5); }
.btn.cta:hover { background: #fff; }
.tile.streak { grid-column: span 3; }
.tile.level { grid-column: span 3; display: flex; flex-direction: column; }
.tile.exams { grid-column: span 6; }
.tile.activity { grid-column: span 5; }
.tile.todo { grid-column: span 7; }
.big-num { font: 800 3.4rem/1 var(--font-display); letter-spacing: -.05em; }
.ring { position: relative; width: 92px; height: 92px; margin: .1rem 0 .4rem; }
.ring svg { transform: rotate(-90deg); width: 100%; height: 100%; }
.ring circle { fill: none; stroke-width: 8; stroke-linecap: round; }
.ring .track { stroke: var(--surface2); } .ring .prog { stroke: var(--primary); transition: stroke-dashoffset .7s cubic-bezier(.2, .8, .2, 1); }
.ring b { position: absolute; inset: 0; display: grid; place-items: center; font: 800 1.5rem var(--font-display); letter-spacing: -.03em; }
.spark { display: flex; align-items: flex-end; gap: 5px; height: 84px; }
.spark i { flex: 1; background: var(--primary); border-radius: 6px 6px 3px 3px; min-height: 4px; }
.spark i.zero { background: var(--surface2); }
@media (max-width: 900px) {
  .tile.hero { grid-column: span 12; grid-row: auto; min-height: 250px; padding: 1.4rem; }
  .tile.streak, .tile.level { grid-column: span 6; }
  .tile.exams, .tile.activity, .tile.todo { grid-column: span 12; }
}

/* tarjetas de asignatura */
.subj {
  --sc: var(--primary); position: relative; display: block; padding: 1.15rem; border-radius: var(--r); text-decoration: none; color: inherit; overflow: hidden;
  background: linear-gradient(180deg, color-mix(in srgb, var(--sc) 14%, var(--surface)) 0%, var(--surface) 62%);
  border: 1px solid color-mix(in srgb, var(--sc) 22%, var(--border)); box-shadow: var(--shadow); transition: transform .16s, box-shadow .16s;
}
.subj:hover { transform: translateY(-3px); box-shadow: var(--shadow-lg); }
.subj-top { display: flex; align-items: flex-start; justify-content: space-between; margin-bottom: 1.1rem; }
.subj-emoji { font-size: 2rem; line-height: 1; width: 52px; height: 52px; display: grid; place-items: center; border-radius: 16px; background: color-mix(in srgb, var(--sc) 20%, var(--surface)); }
.subj-name { display: block; font: 700 1.12rem var(--font-display); letter-spacing: -.02em; }
.subj .bar > i { background: var(--sc); }
.subj-exam { margin-top: .7rem; font-size: .85rem; display: flex; align-items: center; gap: .4rem; flex-wrap: wrap; }

/* ───── markdown ───── */
.md { overflow-wrap: anywhere; }
.md h1, .md h2, .md h3 { margin: 1.1em 0 .4em; } .md p { margin: .65em 0; } .md ul, .md ol { padding-left: 1.3rem; }
.md code { background: var(--surface2); padding: .12em .4em; border-radius: 6px; font-size: .88em; }
.md pre { background: var(--surface2); padding: .9rem; border-radius: 12px; overflow-x: auto; } .md pre code { background: none; padding: 0; }
.md blockquote { border-left: 3px solid var(--primary); margin: .7em 0; padding: .1em 1em; color: var(--muted); }
.md table { border-collapse: collapse; } .md th, .md td { border: 1px solid var(--border-strong); padding: .35rem .65rem; }
.md img { max-width: 100%; border-radius: 10px; }

/* ───── flashcards: ficha de cuaderno ───── */
.study { max-width: 660px; margin: 0 auto; }
.flip { perspective: 1400px; cursor: pointer; }
.flip .inner { position: relative; min-height: 320px; transition: transform .55s cubic-bezier(.3, .8, .2, 1); transform-style: preserve-3d; }
.flip.on .inner { transform: rotateY(180deg); }
.flip .face {
  position: absolute; inset: 0; backface-visibility: hidden; -webkit-backface-visibility: hidden; display: flex; align-items: center; justify-content: center;
  text-align: center; padding: 2rem 1.6rem; border-radius: var(--r-xl); border: 1px solid var(--border); box-shadow: var(--shadow-lg);
  font: 600 1.35rem/1.4 var(--font-display); letter-spacing: -.01em; overflow: auto;
}
.flip .front {
  background:
    linear-gradient(90deg, transparent 2.9rem, color-mix(in srgb, var(--bad) 45%, transparent) 2.9rem 3rem, transparent 3rem),
    repeating-linear-gradient(transparent 0 2.05rem, color-mix(in srgb, var(--primary) 16%, transparent) 2.05rem 2.1rem),
    var(--surface);
}
.flip .back { transform: rotateY(180deg); background: var(--primary-soft); border-color: color-mix(in srgb, var(--primary) 35%, transparent); font-weight: 500; font-family: var(--font); font-size: 1.15rem; }
.flip .face .md p { margin: 0; }
.grades { display: grid; grid-template-columns: repeat(4, 1fr); gap: .55rem; margin-top: 1.1rem; }
.grades .btn { flex-direction: column; gap: 0; padding: .7rem .2rem; font-size: .9rem; border-radius: 16px; }
.grades .btn small { font-weight: 500; color: var(--muted); font-size: .72rem; }

/* ───── tests ───── */
.opt {
  display: flex; gap: .7rem; width: 100%; text-align: left; padding: .85rem 1rem; margin: .5rem 0; border-radius: 15px; border: 1.5px solid var(--border-strong);
  background: var(--surface); cursor: pointer; transition: border-color .15s, background .15s, transform .1s;
}
.opt:hover:not([disabled]) { border-color: var(--primary); transform: translateX(2px); }
.opt.ok { border-color: var(--ok); background: var(--ok-soft); }
.opt.bad { border-color: var(--bad); background: var(--bad-soft); }
.opt[disabled] { cursor: default; color: var(--text); }
.explain { background: var(--warn-soft); border-radius: 14px; padding: .7rem 1rem; margin-top: .7rem; font-size: .92rem; }

/* ───── chat ───── */
.chat { display: flex; flex-direction: column; height: calc(100vh - 300px); min-height: 400px; padding: 1rem; }
.msgs { flex: 1; overflow-y: auto; padding: .4rem; display: flex; flex-direction: column; gap: .8rem; }
.bubble { max-width: 86%; padding: .7rem 1rem; border-radius: 20px; }
.bubble.user { align-self: flex-end; background: var(--primary); color: var(--on-primary); border-bottom-right-radius: 6px; white-space: pre-wrap; }
.bubble.ai { align-self: flex-start; background: var(--surface2); border-bottom-left-radius: 6px; }
.bubble .src { margin-top: .5rem; font-size: .78rem; color: var(--muted); }
.typing { color: var(--muted); }
.composer { display: flex; gap: .5rem; padding-top: .8rem; align-items: flex-end; }
.composer textarea { min-height: 46px; height: 46px; max-height: 140px; border-radius: 16px; }
.composer .btn { height: 46px; border-radius: 16px; }

/* ───── acceso ───── */
.auth { min-height: 100vh; display: grid; grid-template-columns: minmax(0, 1.15fr) minmax(380px, .85fr); }
.auth-hero { padding: clamp(1.5rem, 5vw, 4.5rem); display: flex; flex-direction: column; justify-content: center; gap: 1.4rem; max-width: 760px; }
.auth-hero .brand { padding: 0; }
.auth-hero h1 { font-size: clamp(2.1rem, 4.6vw, 3.7rem); font-weight: 800; letter-spacing: -.045em; margin: 0; max-width: 15ch; }
.auth-hero p { color: var(--muted); font-size: 1.12rem; max-width: 42ch; margin: 0; }
.auth-panel { display: grid; place-items: center; padding: 1.5rem; }
.auth-card { width: 100%; max-width: 400px; background: var(--glass); border: 1px solid var(--border); border-radius: var(--r-xl); padding: 1.5rem; box-shadow: var(--shadow-lg); display: grid; gap: 1rem; -webkit-backdrop-filter: blur(22px); backdrop-filter: blur(22px); }
.demo-card { perspective: 1000px; width: min(100%, 360px); height: 200px; margin-top: .6rem; transform: rotate(-3deg); cursor: pointer; outline-offset: 6px; }
.demo-card .inner { position: relative; width: 100%; height: 100%; transition: transform .6s cubic-bezier(.3, .8, .2, 1); transform-style: preserve-3d; }
.demo-card:hover .inner, .demo-card:focus-visible .inner, .demo-card.on .inner { transform: rotateY(180deg); }
.demo-card .face {
  position: absolute; inset: 0; backface-visibility: hidden; -webkit-backface-visibility: hidden; border-radius: 24px; padding: 1.4rem; display: flex; flex-direction: column; justify-content: center; gap: .3rem;
  border: 1px solid var(--border); box-shadow: var(--shadow-lg); font: 650 1.25rem/1.3 var(--font-display); letter-spacing: -.02em;
}
.demo-card .face small { font: 600 .8rem var(--font); color: var(--muted); }
.demo-card .face p { margin: 0; }
.demo-card .front {
  background: repeating-linear-gradient(transparent 0 1.95rem, color-mix(in srgb, var(--primary) 16%, transparent) 1.95rem 2rem), var(--surface);
}
.demo-card .back { transform: rotateY(180deg); background: var(--mark-solid); color: var(--ink); border-color: transparent; }
@media (max-width: 860px) {
  .auth { grid-template-columns: 1fr; }
  .auth-hero { padding: 1.6rem 1.4rem 0; gap: 1rem; }
  .auth-hero h1 { font-size: 2.1rem; }
  .demo-card { height: 150px; }
  .auth-hero p { font-size: 1rem; }
}

/* ───── modal, aviso ───── */
.modal-bg { position: fixed; inset: 0; background: rgba(8, 10, 24, .5); -webkit-backdrop-filter: blur(6px); backdrop-filter: blur(6px); display: grid; place-items: center; z-index: 50; padding: 1rem; }
.modal { background: var(--surface); border: 1px solid var(--border); border-radius: 26px; width: 100%; max-width: 520px; max-height: 90vh; overflow-y: auto; padding: 1.5rem; box-shadow: var(--shadow-lg); animation: pop .22s cubic-bezier(.2, .9, .3, 1.1); }
@keyframes pop { from { transform: translateY(10px) scale(.97); opacity: 0; } }
#toast {
  position: fixed; left: 50%; bottom: 104px; transform: translateX(-50%) translateY(20px); background: var(--ink); color: #fff; font-weight: 550;
  padding: .7rem 1.2rem; border-radius: 14px; opacity: 0; pointer-events: none; transition: .25s; z-index: 99; max-width: 90vw; text-align: center; box-shadow: var(--shadow-lg);
}
@media (min-width: 901px) { #toast { bottom: 28px; } }
:root[data-theme="dark"] #toast { background: #eef0ff; color: #0e1020; }
#toast.show { opacity: 1; transform: translateX(-50%) translateY(0); }
#toast.err { background: var(--bad); color: #fff; }

/* ───── grupos, tareas, varios ───── */
.lb-row { display: flex; align-items: center; gap: .75rem; padding: .6rem .5rem; border-radius: 14px; }
.lb-row.me { background: var(--primary-soft); font-weight: 600; }
.lb-pos { width: 1.7rem; text-align: center; font: 800 1rem var(--font-display); }
.task.done .t { text-decoration: line-through; color: var(--muted); }
.drop { border: 2px dashed var(--border-strong); border-radius: 16px; padding: 1rem; text-align: center; color: var(--muted); }
.drop.over { border-color: var(--primary); background: var(--primary-soft); }

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