:root {
    --ink: #1d2030;
    --ink-soft: #5d6275;
    --ink-faint: #9095a6;
    --accent: #3d3fc4;
    --accent-soft: #ecedfd;
    --line: #e4e1da;
    --paper: #ffffff;
    --bg: #f5f2ec;
    --red: #c4352b;
    --red-soft: #fdeeec;
    --green: #17804c;
    --green-soft: #e7f5ed;
    /* mastery: one hue, light to dark */
    --lv0: #e9e6df;
    --lv1: #d3d6fb;
    --lv2: #8f97f2;
    --lv3: #3d3fc4;
    --sans: 'Source Sans 3', 'Segoe UI', sans-serif;
    --serif: 'Source Serif 4', Georgia, serif;
}

* { margin: 0; padding: 0; box-sizing: border-box; }

body {
    font-family: var(--serif);
    font-size: 1.05rem;
    line-height: 1.6;
    color: var(--ink);
    background: var(--bg) radial-gradient(#e2ddd3 1px, transparent 1px) 0 0 / 22px 22px;
    min-height: 100vh;
    -webkit-font-smoothing: antialiased;
}

button { font: inherit; color: inherit; }
a { color: var(--accent); }

/* ---------- top bar ---------- */
.top {
    position: sticky;
    top: 0;
    z-index: 10;
    background: rgba(245, 242, 236, .86);
    -webkit-backdrop-filter: blur(10px);
    backdrop-filter: blur(10px);
    border-bottom: 1px solid var(--line);
    font-family: var(--sans);
}
.top-in { max-width: 980px; margin: 0 auto; padding: .55rem 1.2rem; display: flex; align-items: center; gap: 1rem; position: relative; }
.top .home { color: var(--ink-soft); text-decoration: none; font-size: 1.1rem; }
.brand { font-weight: 800; font-size: 1.15rem; color: var(--ink); text-decoration: none; letter-spacing: -.2px; display: flex; align-items: center; gap: .45rem; }
.brand .level { font-size: .7rem; font-weight: 700; background: var(--ink); color: #fff; border-radius: 99px; padding: .1rem .5rem; letter-spacing: .4px; }
.tabs { display: flex; gap: .2rem; margin-left: .6rem; }
.tabs a { color: var(--ink-soft); text-decoration: none; font-weight: 600; padding: .3rem .8rem; border-radius: 99px; }
.tabs a:hover { background: #ebe7df; }
.tabs a.on { background: var(--ink); color: #fff; }
.streak { margin-left: auto; font-size: .9rem; color: var(--ink-soft); }
.streak b { color: var(--accent); font-size: 1.05rem; }
.sound { border: 1px solid var(--line); background: #fff; border-radius: 99px; width: 2.2rem; height: 2.2rem; cursor: pointer; font-size: 1rem; }
.streak:empty + .sound { margin-left: auto; }
.sound.off { opacity: .6; }
.voices {
    position: absolute;
    right: 1.2rem;
    top: 3.1rem;
    width: 19rem;
    background: #fff;
    border: 1px solid var(--line);
    border-radius: 14px;
    box-shadow: 0 12px 34px rgba(30, 30, 60, .14);
    padding: .9rem 1rem 1rem;
    display: grid;
    gap: .5rem;
}
.voices[hidden] { display: none; }
.voices label { font-size: .85rem; font-weight: 700; color: var(--ink-soft); }
.voices select { font: 1rem var(--sans); padding: .4rem .5rem; border: 1px solid #d7d3ca; border-radius: 8px; }
.voices .check { display: flex; gap: .45rem; align-items: center; font-weight: 600; color: var(--ink); }

/* ---------- page ---------- */
#view { max-width: 980px; margin: 0 auto; padding: 1.6rem 1.2rem 4rem; }
#view.in > * { animation: rise .35s cubic-bezier(.2, .7, .2, 1) both; }
#view.in > *:nth-child(2) { animation-delay: .05s; }
#view.in > *:nth-child(3) { animation-delay: .1s; }
#view.in > *:nth-child(4) { animation-delay: .15s; }
@keyframes rise { from { opacity: 0; transform: translateY(10px); } }

.kind { font: 700 .78rem var(--sans); text-transform: uppercase; letter-spacing: .9px; color: var(--ink-faint); display: flex; align-items: center; gap: .4rem; }
.kind a { color: var(--accent); text-decoration: none; text-transform: none; letter-spacing: 0; font-size: .95rem; }
.kind.new { color: var(--accent); }
.kind.bad { color: var(--red); }
.key { font: 700 .7rem var(--sans); color: var(--ink-faint); border: 1px solid #d9d5cc; border-bottom-width: 2px; border-radius: 5px; padding: 0 .35rem; }

.btn {
    font: 700 .95rem var(--sans);
    padding: .5rem 1.1rem;
    border-radius: 99px;
    border: 1.5px solid var(--ink);
    background: var(--ink);
    color: #fff;
    cursor: pointer;
    text-decoration: none;
    display: inline-block;
    transition: transform .12s, box-shadow .12s;
}
.btn:hover { transform: translateY(-1px); box-shadow: 0 6px 16px rgba(30, 30, 60, .18); }
.btn.big { font-size: 1.08rem; padding: .75rem 1.6rem; }
.btn.ghost { background: transparent; color: var(--ink); }
.btn:focus-visible, .opt:focus-visible, .tok:focus-visible { outline: 3px solid var(--lv2); outline-offset: 2px; }

.say { border: 0; background: none; cursor: pointer; font-size: .9rem; margin-left: .4rem; opacity: .45; vertical-align: 1px; transition: opacity .15s, transform .15s; }
.say:hover { opacity: 1; }
.say.on { opacity: 1; transform: scale(1.2); }

/* ---------- today ---------- */
.hero {
    background: var(--ink);
    color: #fff;
    border-radius: 24px;
    padding: 2.2rem 2.4rem 2.4rem;
    position: relative;
    overflow: hidden;
}
.hero::after {
    content: 'the of and to a in';
    position: absolute;
    right: -1rem;
    bottom: -2.2rem;
    font: italic 600 6.5rem/1 var(--serif);
    color: rgba(255, 255, 255, .05);
    white-space: nowrap;
    pointer-events: none;
}
.hero .kicker { font: 700 .82rem var(--sans); text-transform: uppercase; letter-spacing: 1px; color: #a9acd8; }
.hero h1 { font: 800 2.7rem/1.1 var(--sans); letter-spacing: -.8px; margin: .4rem 0 .5rem; }
.hero .sub { color: #c9cbe6; font-size: 1.1rem; max-width: 36rem; margin-bottom: 1.4rem; }
.hero .sub b { color: #fff; }
.hero .btn { background: #fff; color: var(--ink); border-color: #fff; position: relative; z-index: 1; }
.hero .btn.ghost { background: transparent; color: #fff; }

.stats { display: grid; grid-template-columns: repeat(4, 1fr); gap: .8rem; margin: 1rem 0; }
.stat { background: var(--paper); border: 1px solid var(--line); border-radius: 18px; padding: .9rem 1.1rem; font-family: var(--sans); }
.stat b { display: block; font-size: 2rem; font-weight: 800; line-height: 1.1; color: var(--ink); }
.stat span { color: var(--ink-soft); font-size: .9rem; }

.panel, .about, .entry {
    background: var(--paper);
    border: 1px solid var(--line);
    border-radius: 22px;
    padding: 1.4rem 1.6rem 1.6rem;
    margin-bottom: 1rem;
}
.panel-head { display: flex; flex-wrap: wrap; justify-content: space-between; align-items: center; gap: .5rem 1rem; margin-bottom: .9rem; }
.panel h2, .about h2, .summary h3 { font: 800 1.2rem var(--sans); }
.about { background: transparent; border-style: dashed; }
.about p { color: #3b3f52; margin-top: .6rem; max-width: 46rem; }

.legend { display: flex; flex-wrap: wrap; gap: .4rem .9rem; font: 600 .82rem var(--sans); color: var(--ink-soft); }
.legend span { display: inline-flex; align-items: center; gap: .35rem; }
.legend i { width: .8rem; height: .8rem; border-radius: 4px; }

.lv0 { --c: var(--lv0); --t: var(--ink); }
.lv1 { --c: var(--lv1); --t: var(--ink); }
.lv2 { --c: var(--lv2); --t: #fff; }
.lv3 { --c: var(--lv3); --t: #fff; }
.legend i, .dots i { background: var(--c); }

.map { display: flex; flex-wrap: wrap; gap: 5px; }
.tile {
    background: var(--c);
    color: var(--t);
    text-decoration: none;
    border-radius: 9px;
    padding: .3rem .65rem;
    font: 700 .98rem var(--sans);
    display: inline-flex;
    align-items: baseline;
    gap: .35rem;
    transition: transform .12s, box-shadow .12s;
}
.tile:hover { transform: translateY(-2px); box-shadow: 0 6px 14px rgba(30, 30, 60, .16); }
.tile .r { font-size: .7rem; font-weight: 600; opacity: .55; }

.filters { display: flex; flex-wrap: wrap; gap: .6rem; align-items: center; margin-bottom: 1rem; }
#search { font: 1rem var(--sans); padding: .5rem .9rem; border: 1px solid #d7d3ca; border-radius: 99px; width: 14rem; background: #fff; }
.chips { display: flex; flex-wrap: wrap; gap: .35rem; }
.chip { font: 600 .88rem var(--sans); border: 1px solid #d7d3ca; background: #fff; color: var(--ink-soft); padding: .3rem .8rem; border-radius: 99px; cursor: pointer; }
.chip.on { background: var(--ink); border-color: var(--ink); color: #fff; }

.grid { display: grid; grid-template-columns: repeat(auto-fill, minmax(140px, 1fr)); gap: .6rem; }
.tile.big { display: flex; flex-direction: column; align-items: flex-start; gap: 0; padding: .7rem .9rem .75rem; border-radius: 14px; }
.tile.big .w { font-size: 1.45rem; font-weight: 800; letter-spacing: -.3px; }
.tile.big .l { font-size: .78rem; font-weight: 600; opacity: .7; }
.empty { color: var(--ink-soft); font-style: italic; }

/* ---------- a session ---------- */
.session { max-width: 720px; margin: 0 auto; }
.bar { display: flex; align-items: center; gap: .8rem; margin-bottom: 1rem; font-family: var(--sans); }
.quit { font-size: 1.6rem; line-height: 1; color: var(--ink-faint); text-decoration: none; }
.quit:hover { color: var(--ink); }
.meter { flex: 1; height: 8px; background: #e5e1d8; border-radius: 99px; overflow: hidden; }
.meter i { display: block; height: 100%; background: var(--accent); border-radius: 99px; transition: width .4s; }
.count { font-size: .85rem; font-weight: 700; color: var(--ink-soft); min-width: 3.5rem; text-align: right; }

.card {
    background: var(--paper);
    border: 1px solid var(--line);
    border-radius: 26px;
    padding: 1.8rem 2rem 1.8rem;
    box-shadow: 0 1px 2px rgba(0, 0, 0, .04), 0 18px 40px rgba(40, 40, 70, .08);
}
.card.answered.good { box-shadow: 0 0 0 3px var(--green-soft), 0 18px 40px rgba(40, 40, 70, .08); }
.card.answered.bad { box-shadow: 0 0 0 3px var(--red-soft), 0 18px 40px rgba(40, 40, 70, .08); }

.sentence { font: 400 1.95rem/1.45 var(--serif); margin: 1.1rem 0 1.4rem; letter-spacing: -.2px; }
.hint { color: var(--ink-soft); font: .95rem var(--sans); margin-top: .5rem; }
.slot {
    display: inline-block;
    min-width: 4.5rem;
    height: 1.25em;
    vertical-align: -.2em;
    border-radius: 10px;
    border: 2px dashed var(--lv2);
    background: var(--accent-soft);
    animation: breathe 1.8s ease-in-out infinite;
    text-align: center;
    line-height: 1.15em;
}
.slot.filled { animation: pop .3s ease-out; border: 2px solid var(--green); background: var(--green-soft); color: var(--green); font-weight: 600; padding: 0 .4rem; width: auto; height: auto; }
@keyframes breathe { 50% { border-color: var(--accent); } }
@keyframes pop { 0% { transform: scale(.7); } 70% { transform: scale(1.08); } }

.opts { display: flex; flex-wrap: wrap; gap: .6rem; }
.opts.stack { flex-direction: column; margin-top: 1.2rem; }
.opt {
    font: 600 1.15rem var(--sans);
    border: 1.5px solid #d7d3ca;
    border-bottom-width: 3px;
    background: #fff;
    border-radius: 14px;
    padding: .6rem 1.2rem;
    cursor: pointer;
    display: inline-flex;
    align-items: center;
    gap: .6rem;
    transition: transform .1s, border-color .1s, background .1s;
}
.opt:hover:not(:disabled) { border-color: var(--accent); background: var(--accent-soft); transform: translateY(-1px); }
.opt:active:not(:disabled) { transform: translateY(1px); border-bottom-width: 1.5px; }
.opt.sent { font: 400 1.3rem var(--serif); text-align: left; padding: .8rem 1.1rem; }
.opt.sent .key { font-family: var(--sans); }
.opt:disabled { cursor: default; }
.opt.right { border-color: var(--green); background: var(--green-soft); color: var(--green); }
.opt.wrong { border-color: var(--red); background: var(--red-soft); color: var(--red); animation: shake .35s; }
.opt.struck:not(.right) { text-decoration: line-through; color: var(--ink-faint); }
.opt:disabled:not(.right):not(.wrong) { opacity: .55; }
@keyframes shake { 25% { transform: translateX(-5px); } 75% { transform: translateX(5px); } }

.toks { display: flex; flex-wrap: wrap; gap: .15rem .1rem; }
.tok {
    font: inherit;
    border: 0;
    background: none;
    padding: 0 .3rem;
    border-radius: 8px;
    cursor: pointer;
    border-bottom: 2px solid transparent;
    transition: background .12s;
}
.tok:hover:not(:disabled) { background: var(--accent-soft); border-bottom-color: var(--lv2); }
.tok:disabled { cursor: default; }
.tok.bad { color: var(--red); text-decoration: line-through wavy var(--red); text-decoration-thickness: 1.5px; background: var(--red-soft); }
.tok.miss { box-shadow: inset 0 0 0 2px var(--ink-faint); }

.fb:empty { display: none; }
.fb { margin-top: 1.4rem; padding-top: 1.2rem; border-top: 1px solid var(--line); animation: rise .3s ease-out; }
.verdict { font: 700 1.05rem var(--sans); }
.good .verdict { color: var(--green); }
.bad .verdict { color: var(--red); }
.answer { font: 600 1.25rem var(--serif); margin: .3rem 0 .9rem; }

.why { display: flex; gap: .8rem; background: #f8f6f2; border-radius: 16px; padding: .9rem 1rem; }
.why p { margin-bottom: .2rem; }
.num {
    flex: 0 0 auto;
    width: 1.7rem;
    height: 1.7rem;
    border-radius: 50%;
    background: var(--accent);
    color: #fff;
    font: 700 .9rem var(--sans);
    display: grid;
    place-items: center;
    margin-top: .1rem;
}
.why.careful .num { background: var(--red); }
.ex { font-style: italic; color: #3a3f5c; padding-left: .9rem; border-left: 3px solid var(--lv1); margin: .2rem 0; }

.actions { display: flex; flex-wrap: wrap; align-items: center; gap: .8rem; margin-top: 1.4rem; }

/* the card that introduces a new word */
.intro-head { display: flex; align-items: center; gap: .3rem; }
.word { font: 800 4rem/1.05 var(--sans); letter-spacing: -2px; color: var(--ink); }
.intro-head .say { font-size: 1.3rem; }
.forms { color: var(--ink-soft); font-family: var(--sans); }
.tag { display: inline-block; font: 700 .78rem var(--sans); color: var(--accent); background: var(--accent-soft); border-radius: 99px; padding: .15rem .65rem; margin-top: .5rem; }
.uses { list-style: none; counter-reset: use; margin: 1.3rem 0 1rem; display: grid; gap: .9rem; }
.uses > li { counter-increment: use; position: relative; padding-left: 2.4rem; }
.uses:not(.full) > li::before {
    content: counter(use);
    position: absolute;
    left: 0;
    top: .1rem;
    width: 1.7rem;
    height: 1.7rem;
    border-radius: 50%;
    background: var(--accent);
    color: #fff;
    font: 700 .9rem var(--sans);
    display: grid;
    place-items: center;
}
.uses.full > li { padding-left: 0; display: flex; gap: .8rem; }
.uses b, .why b, .about b { color: var(--accent); }
.watch { background: var(--red-soft); border-radius: 16px; padding: .9rem 1.1rem; }
.watch p { font-size: .97rem; color: #5a3f3b; margin-top: .2rem; }
.watch .pair + .pair, .watch p + .pair { margin-top: .6rem; }
.pair { display: flex; flex-wrap: wrap; align-items: baseline; gap: .2rem .9rem; margin-top: .3rem; }
.pair s { color: var(--red); text-decoration-color: var(--red); }
.pair s::before { content: '\2717  '; text-decoration: none; display: inline-block; margin-right: .3rem; }
.pair span { font-weight: 600; color: var(--green); }
.pair span::before { content: '\2713'; margin-right: .4rem; }
.why .pair { margin: 0 0 .3rem; }

/* summary */
.summary .score { display: flex; align-items: baseline; gap: .7rem; font-family: var(--sans); margin: .4rem 0 .8rem; }
.summary .score b { font-size: 4rem; font-weight: 800; line-height: 1; color: var(--accent); }
.summary .score span { color: var(--ink-soft); font-size: 1.1rem; }
.summary p { margin-bottom: .6rem; }
.summary h3 { margin: 1.3rem 0 .4rem; }
.summary .legend { margin-bottom: .6rem; }

/* ---------- one entry ---------- */
.entry-head { display: flex; flex-wrap: wrap; justify-content: space-between; align-items: flex-end; gap: 1rem; padding-bottom: 1rem; border-bottom: 1px solid var(--line); }
.entry-side { display: flex; align-items: center; gap: .7rem; }
.badge { font: 700 .82rem var(--sans); background: var(--c); color: var(--t); border-radius: 99px; padding: .25rem .8rem; }
.dots { display: inline-flex; gap: 3px; margin-left: .5rem; vertical-align: 1px; }
.dots i { width: .6rem; height: .6rem; border-radius: 3px; box-shadow: inset 0 0 0 1px rgba(0, 0, 0, .06); }
.pager { display: flex; justify-content: space-between; margin-top: 1.4rem; }

@media (max-width: 720px) {
    .top-in { gap: .5rem; padding: .5rem .8rem; }
    .brand .level, .streak { display: none; }
    .tabs { margin-left: auto; }
    #view { padding: 1rem .7rem 3rem; }
    .hero { padding: 1.6rem 1.4rem 1.8rem; border-radius: 20px; }
    .hero h1 { font-size: 2rem; }
    .stats { grid-template-columns: repeat(2, 1fr); }
    .panel, .about, .entry { padding: 1.1rem 1rem 1.2rem; }
    .card { padding: 1.3rem 1.1rem; border-radius: 20px; }
    .sentence { font-size: 1.5rem; }
    .word { font-size: 3rem; }
    .opt { flex: 1 1 auto; justify-content: center; }
    #search { width: 100%; }
}