:root{
  color-scheme:light;
  /* Neutrals: page, cards, ink, and a grey ramp from light fills to dark text. */
  --bg:#f5f7fb;--surface:#fff;--ink:#18212f;--on-ink:#fff;
  --gray-100:#f1f4f8;--gray-150:#eef2f7;--gray-200:#e9edf4;--gray-300:#e1e6ee;--gray-400:#cfd6e2;
  --gray-500:#b7c0cd;--gray-600:#8a94a3;--gray-700:#69768a;--gray-800:#536174;--gray-900:#223047;
  /* Accent (pinyin, custom tags, selection, focus). */
  --accent:#4c6fff;--accent-ink:#3f4fb8;--accent-100:#eef1ff;--accent-200:#e3e9ff;--accent-300:#d5dcff;
  /* Wrong / delete, and right / saved. */
  --red:#b42338;--red-ink:#9e3647;--red-muted:#9b5360;--red-100:#fff4f6;--red-200:#e3c0c6;--red-300:#e3a3ad;
  --green:#1c7c4a;--green-ink:#36724e;--green-50:#f6faf7;--green-100:#eef8f1;--green-200:#cfe3d6;--green-300:#a9d3b8;
  /* The user's own definitions. */
  --own:#7a55c7;--own-ink:#4b2f91;--own-100:#f5f1fd;--own-200:#ebe3fa;--own-300:#dccff6;
  --highlight:#ffe9a8;
  /* Notices (e.g. "verify your email address"). */
  --amber-100:#fff7e0;--amber-300:#efd28a;--amber-ink:#6d5200;
  --shadow-rgb:24 33 47; /* shadows are this colour at low opacity */
}
:root{font-family:Inter,ui-sans-serif,system-ui,-apple-system,BlinkMacSystemFont,"Segoe UI","Noto Sans SC",sans-serif;color:var(--ink);background:var(--bg);line-height:1.5}*{box-sizing:border-box}body{margin:0}.topbar{height:64px;background:var(--surface);border-bottom:1px solid var(--gray-300);display:flex;align-items:center;justify-content:space-between;padding:0 28px;position:sticky;top:0;z-index:5}.brand{font-weight:800;letter-spacing:-.02em}.brand span{font-weight:500;color:var(--gray-700)}nav{display:flex;gap:8px}.nav-btn{border:0;background:transparent;padding:9px 12px;border-radius:8px;color:var(--gray-800);cursor:pointer}.nav-btn.active,.nav-btn:hover{background:var(--gray-150);color:var(--ink)}.nav-btn.ghost{color:var(--red-muted)}.shell{max-width:1040px;margin:0 auto;padding:30px 20px 80px}.auth-card{max-width:560px;background:var(--surface);border:1px solid var(--gray-300);border-radius:16px;padding:34px;box-shadow:0 12px 40px rgb(var(--shadow-rgb) / .07);margin:50px auto}.auth-card h1{font-size:34px;line-height:1.12;margin:8px 0 14px;letter-spacing:-.03em}.eyebrow{text-transform:uppercase;letter-spacing:.12em;font-size:12px;font-weight:800;color:var(--gray-700)}.muted{color:var(--gray-700)}.tabs{display:flex;gap:4px;border-bottom:1px solid var(--gray-300);margin:28px 0 22px}.tab{border:0;background:transparent;padding:10px 12px;color:var(--gray-700);cursor:pointer;border-bottom:2px solid transparent}.tab.active{color:var(--ink);border-bottom-color:var(--ink)}.hidden{display:none!important}label{display:block;font-size:14px;font-weight:700;margin:14px 0}input{width:100%;margin-top:7px;padding:11px 12px;border:1px solid var(--gray-400);border-radius:8px;font-size:16px}.primary,.secondary{border:0;border-radius:9px;padding:11px 15px;font-weight:700;cursor:pointer}.primary{background:var(--ink);color:var(--on-ink)}.secondary{background:var(--gray-150);color:var(--gray-900)}.primary:disabled{opacity:.45;cursor:not-allowed}.error{color:var(--red);font-size:13px;margin-top:10px;min-height:20px}.page-head{display:flex;justify-content:space-between;align-items:center;gap:20px;margin-bottom:24px}.page-head h2{font-size:34px;line-height:1.15;margin:6px 0}.stats{display:grid;grid-template-columns:repeat(3,1fr);gap:12px;margin-bottom:22px}.stat{background:var(--surface);border:1px solid var(--gray-300);border-radius:12px;padding:18px}.stat .value{font-size:28px;font-weight:800}.stat .label{font-size:13px;color:var(--gray-700)}.test-grid{display:grid;grid-template-columns:repeat(2,1fr);gap:16px}.test-card{background:var(--surface);border:1px solid var(--gray-300);border-radius:14px;padding:22px}.test-icon{font-size:30px;font-weight:800;margin-bottom:8px}.test-card h3{margin:0 0 7px}.test-card p{color:var(--gray-700);min-height:64px}.test-header{display:flex;justify-content:space-between;align-items:center;margin-bottom:14px}.link-btn{border:0;background:transparent;padding:8px 0;color:var(--gray-800);cursor:pointer}.quiz-card,.flash-card{max-width:780px;margin:32px auto;background:var(--surface);border:1px solid var(--gray-300);border-radius:16px;padding:36px;text-align:center}.hanzi{font-size:64px;font-weight:700;letter-spacing:.04em;margin:20px 0 26px}.options{display:grid;grid-template-columns:1fr 1fr;gap:12px;text-align:left}.option{background:var(--surface);border:1px solid var(--gray-400);border-radius:10px;padding:16px;cursor:pointer;font-size:16px;font-family:"Noto Sans","Noto Sans SC",sans-serif}.stack{display:grid;gap:12px}.wrong-item,.review-item{background:var(--surface);border:1px solid var(--gray-300);border-radius:12px;padding:18px;display:flex;align-items:center;justify-content:space-between;gap:18px}.wrong-main,.review-main{min-width:0}.wrong-hanzi,.review-hanzi{font-size:28px;font-weight:800}.meta{font-size:13px;color:var(--gray-700)}.wrong-choice{color:var(--red-ink)}.right-choice{color:var(--green-ink)}.flash-answer{display:none;margin-top:10px;font-size:20px}.flash-card .hanzi{margin-bottom:10px}.success{color:var(--green-ink)}.review-actions{display:flex;gap:8px}
@media(max-width:800px){.test-grid{grid-template-columns:1fr}.stats{grid-template-columns:1fr}.options{grid-template-columns:1fr}.topbar{padding:0 14px}.brand{font-size:14px}nav{gap:2px}.nav-btn{padding:8px 7px}.shell{padding-top:26px}.quiz-card,.flash-card{padding:24px 18px}.page-head{align-items:start;flex-direction:column}.auth-card{margin:20px auto;padding:24px}}
.level-estimate{font-size:13px;color:var(--gray-800);margin:0 0 12px;min-height:20px}.level-badge{display:inline-block;background:var(--gray-150);color:var(--gray-900);border-radius:999px;padding:3px 10px;font-size:13px;font-weight:700}
.option.dont-know{grid-column:1/-1;justify-self:center;width:100%;font-size:larger;background:transparent;border:1px dashed var(--gray-500);border-radius:999px;padding:9px 22px;color:var(--gray-700);text-align:center}.option.dont-know:disabled{opacity:.5;cursor:default}
.option{transition:background .12s,border-color .12s,box-shadow .12s,transform .12s}.option:hover:not(:disabled){background:var(--ink);border-color:var(--ink);color:var(--on-ink);box-shadow:0 4px 14px rgb(var(--shadow-rgb) / .18);transform:translateY(-1px)}.option:active:not(:disabled){transform:translateY(0);box-shadow:0 1px 4px rgb(var(--shadow-rgb) / .15)}.option:focus-visible{outline:2px solid var(--accent);outline-offset:2px}.option:disabled{cursor:default}.option.dont-know:hover:not(:disabled){background:var(--gray-100);border-color:var(--gray-600);border-style:solid;color:var(--gray-900);box-shadow:none;transform:none}
.tag-row{display:flex;flex-wrap:wrap;gap:6px;margin-top:8px}.tag-row:empty{display:none}
.tag-chip{display:inline-flex;align-items:center;gap:4px;background:var(--gray-100);border:1px solid var(--gray-300);border-radius:999px;padding:3px 10px;font-size:13px;color:var(--gray-900);line-height:1.4;font-family:inherit}
.tag-chip.custom{background:var(--accent-100);border-color:var(--accent-300);color:var(--accent-ink)}
.tag-chip.toggle{cursor:pointer;background:var(--surface)}.tag-chip.toggle:hover{border-color:var(--gray-600)}
.tag-chip.toggle.on{background:var(--ink);border-color:var(--ink);color:var(--on-ink)}
.chip-x{border:0;background:transparent;color:inherit;cursor:pointer;font-size:15px;line-height:1;padding:0 0 0 2px;opacity:.6}.chip-x:hover{opacity:1}
.tag-filter{display:flex;flex-wrap:wrap;gap:6px;margin-bottom:14px}.tag-filter:empty{display:none}
.tag-manager{background:var(--surface);border:1px solid var(--gray-300);border-radius:12px;padding:12px 16px;margin-bottom:16px}
.tag-manager summary{cursor:pointer;font-weight:700;font-size:14px;color:var(--gray-800)}
.inline-form{display:flex;gap:8px;align-items:center;margin-top:10px}.inline-form input{margin-top:0;flex:1;min-width:0}
.review-hanzi.long,.hanzi.long{font-size:22px;font-weight:700;letter-spacing:0}
.wb-form{margin:0 0 6px}.wb-form input{font-size:18px;padding:13px 14px}
#wb-count{margin-bottom:16px}
.wb-lines{display:grid;gap:10px}
.wb-line{background:var(--surface);border:1px solid var(--gray-300);border-radius:12px;padding:14px 16px;display:flex;align-items:flex-start;justify-content:space-between;gap:14px}
.wb-line.sent{background:var(--green-50);border-color:var(--green-200)}
.wb-body{min-width:0;flex:1}
.wb-text{font-size:22px;font-family:"Noto Sans","Noto Sans SC",sans-serif;overflow-wrap:anywhere}
.wb-controls{display:flex;gap:6px;flex-shrink:0}
.icon-btn{width:38px;height:38px;border:1px solid var(--gray-400);border-radius:9px;background:var(--surface);cursor:pointer;font-size:16px;line-height:1;display:inline-flex;align-items:center;justify-content:center;color:var(--gray-900)}
.icon-btn:hover:not(:disabled){background:var(--gray-100);border-color:var(--gray-600)}
.icon-btn.on{background:var(--ink);border-color:var(--ink);color:var(--on-ink)}
.icon-btn:disabled{cursor:default;opacity:.55}
.wb-line.sent .wb-send:disabled{opacity:1;color:var(--green);border-color:var(--green-300);background:var(--green-100)}
.wb-del:hover:not(:disabled){color:var(--red);border-color:var(--red-300);background:var(--red-100)}
.wb-empty{padding:18px 4px}
#wb-new,#save-all-wrong{border:2px solid var(--gray-400)}  /* page-head buttons on the page background */
@media(max-width:600px){.wb-line{flex-direction:column}.wb-controls{align-self:flex-end}}
.secondary:disabled{opacity:.45;cursor:not-allowed}
.wb-line{position:relative}
.wb-tok{font:inherit;color:inherit;background:transparent;border:0;border-bottom:2px dotted var(--gray-500);border-radius:4px 4px 0 0;padding:0 1px;margin:0 3px;cursor:pointer;line-height:1.5}
.wb-tok:hover{background:var(--gray-150);border-bottom-color:var(--gray-800)}
.wb-tok.open{background:var(--ink);color:var(--on-ink);border-bottom-color:var(--ink)}
.wb-tok.unknown{border-bottom-color:var(--red-200)}
.wb-pop{position:absolute;z-index:20;width:min(380px,calc(100% - 16px));background:var(--surface);border:1px solid var(--gray-400);border-radius:12px;box-shadow:0 12px 32px rgb(var(--shadow-rgb) / .16);padding:14px 16px;text-align:left}
.wb-pop-head{display:flex;justify-content:space-between;align-items:center;gap:10px}
.wb-pop-word{font-size:28px;font-weight:700;font-family:"Noto Sans","Noto Sans SC",sans-serif}
.wb-pop-close{border:0;background:transparent;font-size:16px;color:var(--gray-700);cursor:pointer;padding:4px}.wb-pop-close:hover{color:var(--ink)}
.wb-pop-pinyin{font-size:18px;font-weight:700;color:var(--ink);margin-top:2px}
.wb-pop-def{margin-top:4px;color:var(--gray-900);font-size:15px}
.wb-pop-label{font-size:12px;font-weight:700;color:var(--gray-700);margin:12px 0 0;text-transform:uppercase;letter-spacing:.06em}
.wb-pop-select{display:block;width:100%;margin-top:6px;padding:8px 10px;border:1px solid var(--gray-400);border-radius:8px;font-size:14px;background:var(--surface);text-transform:none;letter-spacing:0;font-weight:400;color:var(--ink)}
.wb-pop-actions{display:flex;gap:8px;margin-top:12px}.wb-pop-actions .secondary{flex:1;padding:9px 10px}
.result-wide{grid-column:1/-1;justify-self:center}
.hanzi .blank{display:inline-block;width:.9em;height:.9em;border-bottom:4px solid var(--gray-500);margin:0 .06em;vertical-align:-.08em}
.options.hanzi-options .option:not(.dont-know){font-size:32px;line-height:1.2;text-align:center;padding:12px}
.review-search{position:relative;margin-bottom:12px}.review-search input{margin-top:0;font-size:16px}
.suggest{position:absolute;left:0;right:0;top:calc(100% + 4px);z-index:10;background:var(--surface);border:1px solid var(--gray-400);border-radius:10px;box-shadow:0 12px 32px rgb(var(--shadow-rgb) / .14);padding:4px;max-height:360px;overflow-y:auto}
.suggest-item{display:flex;align-items:baseline;gap:10px;padding:8px 10px;border-radius:7px;cursor:pointer;min-width:0}
.suggest-item.active,.suggest-item:hover{background:var(--gray-150)}
.suggest-hanzi{font-size:18px;font-weight:700;font-family:"Noto Sans","Noto Sans SC",sans-serif;flex-shrink:0}
.suggest-pinyin{color:var(--accent-ink);flex-shrink:0}
.suggest-def{color:var(--gray-800);font-size:14px;white-space:nowrap;overflow:hidden;text-overflow:ellipsis;min-width:0}
.suggest-kind{margin-left:auto;font-size:12px;color:var(--gray-600);flex-shrink:0;padding-left:8px}
.suggest mark{background:var(--highlight);color:inherit;border-radius:3px;padding:0 1px}
.missed-head{grid-column:1/-1;text-align:left;margin-top:4px}
.missed{grid-column:1/-1;list-style:none;padding:0;margin:0 0 6px;display:grid;grid-template-columns:repeat(auto-fill,minmax(150px,1fr));gap:8px;text-align:left}
.missed li{background:var(--bg);border-radius:8px;padding:8px 10px;min-width:0}
.missed-hanzi{font-size:30px;font-weight:700;line-height:1.25;font-family:"Noto Sans","Noto Sans SC",sans-serif;overflow-wrap:anywhere}
.missed-sub{display:flex;flex-wrap:wrap;align-items:baseline;gap:0 8px;font-size:14px;color:var(--gray-800);font-family:"Noto Sans","Noto Sans SC",sans-serif}
.missed-pinyin{color:var(--accent-ink)}
.hanzi,.wrong-hanzi,.review-hanzi,.test-icon{font-family:"Noto Sans","Noto Sans SC",sans-serif}
/* The top bar never widens the page: its buttons scroll inside it instead. */
.topbar{gap:12px}.brand{flex-shrink:0;white-space:nowrap}
nav{min-width:0;overflow-x:auto;scrollbar-width:thin;overscroll-behavior-x:contain}.nav-btn{flex-shrink:0;white-space:nowrap}
/* Review book chip rows (filter, item tags, tag picker, custom tags) stay on one line and scroll. */
#review-view .tag-filter,#review-view .tag-row{flex-wrap:nowrap;overflow-x:auto;scrollbar-width:thin;overscroll-behavior-x:contain;padding-bottom:4px}
#review-view .tag-chip{flex-shrink:0;white-space:nowrap}
.review-item{min-width:0}.review-main{flex:1 1 auto}.review-actions{flex-shrink:0}
@media(max-width:600px){.review-item{flex-direction:column;align-items:stretch}.review-actions{align-self:flex-end}}
/* Whiteboard: words picked for merging, the merge bar, and a line being edited. */
.wb-tok.sel{background:var(--accent-200);border-bottom-color:var(--accent);color:var(--accent-ink)}.wb-tok.sel:hover{background:var(--accent-300)}
.wb-select-bar{display:flex;flex-wrap:wrap;align-items:center;justify-content:space-between;gap:6px 12px;margin-top:8px;padding:8px 10px;background:var(--accent-100);border:1px solid var(--accent-300);border-radius:9px;font-size:14px}
.wb-select-bar strong{font-family:"Noto Sans","Noto Sans SC",sans-serif}
.wb-select-actions{display:flex;gap:10px;align-items:center}.wb-select-actions .secondary{padding:7px 12px}
.wb-line.editing{border-style:dashed;border-color:var(--gray-600)}.wb-line.editing .wb-text{color:var(--gray-600)}
.remove-review:hover:not(:disabled){color:var(--red);border-color:var(--red-300);background:var(--red-100)}
/* Wrong answers: the selected mistake's card above grids of mistakes by period. */
.wrong-group{margin-top:22px}.wrong-group .eyebrow{margin-bottom:8px}
.missed.pickable li{padding:0}
.missed-pick{all:unset;box-sizing:border-box;display:block;width:100%;height:100%;padding:8px 10px;border-radius:8px;cursor:pointer}
.missed-pick:hover{background:var(--gray-200)}.missed-pick.selected{background:var(--gray-200);box-shadow:inset 0 0 0 2px var(--ink)}
.missed-pick:focus-visible{outline:2px solid var(--accent);outline-offset:2px}
.save-review.saved:disabled{opacity:1;color:var(--green);border-color:var(--green-300);background:var(--green-100)}
/* On the page background (not a white card, as on the results screen), cells are white. */
.missed.pickable li{background:var(--surface);border:1px solid var(--gray-300)}
.missed.pickable li.saved{background:var(--gray-150)}
/* The corner badge on save buttons counts the item's saves from this page. */
.icon-btn{position:relative}
.save-count{position:absolute;top:-7px;right:-7px;min-width:18px;height:18px;padding:0 5px;border-radius:9px;background:var(--green);color:var(--on-ink);font-size:11px;font-weight:700;line-height:18px;text-align:center}
/* The user's own definitions (#11): words showing one are violet, and selected in violet. */
.wb-tok.custom{color:var(--own)}
.wb-pop-pinyin.own{color:var(--accent-ink)}
.wb-tok.custom.open{background:var(--own-ink);border-bottom-color:var(--own-ink)}
.wb-tok.custom.sel{background:var(--own-200);border-bottom-color:var(--own);color:var(--own-ink)}.wb-tok.custom.sel:hover{background:var(--own-300)}
.own-badge{display:inline-block;margin-top:4px;padding:1px 8px;border-radius:999px;background:var(--own-100);border:1px solid var(--own-300);color:var(--own-ink);font-size:11px;font-weight:700;text-transform:uppercase;letter-spacing:.06em;line-height:1.6}
.own-badge.inline{margin:0 0 0 6px;vertical-align:1px}
.wb-def-open{display:block;padding:10px 0 0;font-size:14px;color:var(--own-ink)}.wb-def-open:hover{text-decoration:underline}
.wb-def-form input{margin-top:6px;padding:8px 10px;font-size:15px;font-weight:400;text-transform:none;letter-spacing:0}
.wb-def-actions{display:flex;align-items:center;gap:8px;margin-top:12px}.wb-def-actions .primary,.wb-def-actions .secondary{padding:8px 14px}
.wb-def-delete{margin-left:auto;color:var(--red-muted)}
/* Profile: display name, invites, friends and blocked users; the Profile tab counts invites. */
.nav-count{display:inline-block;min-width:18px;height:18px;padding:0 5px;margin-left:6px;border-radius:9px;background:var(--red);color:var(--on-ink);font-size:11px;font-weight:700;line-height:18px;text-align:center;vertical-align:1px}
.profile-card{background:var(--surface);border:1px solid var(--gray-300);border-radius:12px;padding:16px 18px}
.profile-card .error:empty{min-height:0;margin:0}
.profile-section{margin-top:26px}.profile-section h3{margin:0 0 10px;font-size:18px}
.person{background:var(--surface);border:1px solid var(--gray-300);border-radius:12px;padding:14px 16px;display:flex;align-items:center;justify-content:space-between;gap:14px}
.person+.person{margin-top:10px}
.person-main{min-width:0}.person-name{font-size:17px;overflow-wrap:anywhere}
.person-actions{display:flex;gap:8px;align-items:center;flex-shrink:0}.person-actions .primary,.person-actions .secondary{padding:9px 13px}
.friend-levels{display:flex;flex-wrap:wrap;gap:2px 16px;font-size:14px;margin-top:4px}
.link-btn.danger{color:var(--red-muted)}.link-btn.danger:hover{color:var(--red)}
.friend-remove:hover:not(:disabled){color:var(--red);border-color:var(--red-300);background:var(--red-100)}
#blocked-box .person{border-color:var(--gray-200)}#blocked-box .person:first-of-type{margin-top:10px}
@media(max-width:600px){.person{flex-direction:column;align-items:stretch}.person-actions{align-self:flex-end}}
/* Profile: changing the email address. */
.email-line .link-btn{padding:0 0 0 6px;font-size:13px;text-decoration:underline}
.email-change{flex-wrap:wrap}.email-change input{min-width:180px}
.email-pending{display:flex;flex-wrap:wrap;align-items:baseline;gap:4px 14px;margin-top:8px;font-size:14px;color:var(--amber-ink)}
.email-pending .link-btn{padding:0;font-size:13px;text-decoration:underline}
/* Email verification: a notice until the address is verified, briefly green once it is. */
.verify-banner{display:flex;flex-wrap:wrap;align-items:center;gap:8px 14px;margin:0 0 20px;padding:11px 16px;border-radius:12px;background:var(--amber-100);border:1px solid var(--amber-300);color:var(--amber-ink);font-size:14px}
.verify-banner .secondary{padding:7px 12px;margin-left:auto}
.verify-banner.done{background:var(--green-100);border-color:var(--green-200);color:var(--green-ink)}
#verify-result{font-weight:700}#verify-result:empty{display:none}
/* Log in / create account / password reset. */
.auth-title{margin:26px 0 4px;font-size:20px}
.auth-actions{display:flex;flex-wrap:wrap;align-items:center;gap:10px 18px}
.auth-note{margin:4px 0 0;padding:12px 14px;border-radius:9px;background:var(--green-100);border:1px solid var(--green-200);color:var(--green-ink);font-size:14px}
/* Whiteboard on wider screens: the page fills the window and the line list scrolls, so the
   input stays in view. */
@media(min-width:801px){
.shell:has(#whiteboard-view:not(.hidden)){padding-bottom:24px}
#whiteboard-view{display:flex;flex-direction:column;height:calc(100vh - 118px);min-height:360px}
#whiteboard-view .wb-lines{flex:1 1 auto;min-height:0;overflow-y:auto;align-content:start;padding:0 6px 12px 0;scrollbar-width:thin}
}
/* Selected words (popup open, or picked for merging) and open tag pickers get a ring of
   marching dots (ringHtml, fitRings in app.js) in the state's colour (--ring), with corners
   concentric with the element's; still for people who prefer reduced motion. Offsets are
   from the padding box: tokens have a 2px underline below it, icon buttons a 1px border. */
.wb-tok.open,.wb-tok.sel{position:relative;border-radius:4px}
.wb-tok.open{--ring:var(--ink)}.wb-tok.open.custom{--ring:var(--own-ink)}
.wb-tok.sel{--ring:var(--accent)}.wb-tok.sel.custom{--ring:var(--own)}
.wb-tag.on,.edit-tags.on{--ring:var(--ink)}
.ring{position:absolute;left:-2px;top:-2px;width:calc(100% + 4px);height:calc(100% + 6px);overflow:visible;pointer-events:none}
.icon-btn .ring{left:-4px;top:-4px;width:calc(100% + 8px);height:calc(100% + 8px)}
.ring path{fill:none;stroke:var(--ring);stroke-width:2;stroke-linecap:round}