/* Maths Connections — design system */
/* Colours and type follow the main Mr Wells Maths site (assets/css/site.css). */
:root{
  --paper:#f4f6fb; --paper-2:#EFF3F9; --paper-3:#e3e9f3;
  --line:#d8e0ee;
  --ink:#002060; --text:#1a1a1a; --ink-soft:#5a6478; --ink-faint:#8a93a6;
  --tile-bg:#FFFFFF; --tile-border:#002060; --tile-shadow:rgba(0,32,96,0.10);
  --accent-1:#9A6F00; --accent-1-bg:#F7ECCB;   /* gold   */
  --accent-2:#1E7A3C; --accent-2-bg:#DCEFE2;   /* green  */
  --accent-3:#6A3FA0; --accent-3-bg:#EAE1F5;   /* purple */
  --accent-4:#2E6F9E; --accent-4-bg:#DCEAF6;   /* blue   */
  --danger:#C8102E; --danger-bg:#FBE0E4;
  --focus:#002060;
  --radius:12px;
}
@media (prefers-color-scheme: dark){
  :root:not([data-theme="light"]){
    --paper:#0d1424; --paper-2:#141d31; --paper-3:#1b263d;
    --line:rgba(199,211,234,0.16);
    --ink:#dfe7f6; --text:#e8edf6; --ink-soft:#a7b3c9; --ink-faint:#6f7b92;
    --tile-bg:#18223a; --tile-border:#3a4a6b; --tile-shadow:rgba(0,0,0,0.35);
    --accent-1:#E2B645; --accent-1-bg:#3a2f12;
    --accent-2:#4CC47A; --accent-2-bg:#12321f;
    --accent-3:#B592E6; --accent-3-bg:#2c2044;
    --accent-4:#6FB0E6; --accent-4-bg:#152c44;
    --danger:#F0788A; --danger-bg:#3a1b22;
    --focus:#dfe7f6;
  }
}
:root[data-theme="dark"]{
  --paper:#0d1424; --paper-2:#141d31; --paper-3:#1b263d;
  --line:rgba(199,211,234,0.16);
  --ink:#dfe7f6; --text:#e8edf6; --ink-soft:#a7b3c9; --ink-faint:#6f7b92;
  --tile-bg:#18223a; --tile-border:#3a4a6b; --tile-shadow:rgba(0,0,0,0.35);
  --accent-1:#E2B645; --accent-1-bg:#3a2f12;
  --accent-2:#4CC47A; --accent-2-bg:#12321f;
  --accent-3:#B592E6; --accent-3-bg:#2c2044;
  --accent-4:#6FB0E6; --accent-4-bg:#152c44;
  --danger:#F0788A; --danger-bg:#3a1b22;
  --focus:#dfe7f6;
}

*{ box-sizing:border-box; }
html{ height:100%; }
body{
  margin:0; min-height:100%;
  background:var(--paper);
  color:var(--text);
  font-family:"Segoe UI",Aptos,Calibri,Arial,sans-serif;
  padding-block:22px 60px;
  -webkit-font-smoothing:antialiased;
}
a{ color:inherit; }
button{ font-family:inherit; }
.katex{ font-size:1em; }
.wrap{ max-width:600px; margin:0 auto; padding:0 16px; }
.wrap.wide{ max-width:980px; }
.hidden{ display:none !important; }

/* ---------- top bar ---------- */
.topbar{ display:flex; align-items:center; justify-content:space-between; gap:10px; margin-bottom:14px; }
.topbar .left, .topbar .right{ display:flex; align-items:center; gap:8px; }
.icon-btn{
  text-decoration:none; display:inline-block;
  background:none; border:1.5px solid var(--ink); color:var(--ink); border-radius:9px;
  padding:6px 12px; font-weight:700; font-size:0.8rem; cursor:pointer; transition:background .15s,color .15s;
  white-space:nowrap;
}
.icon-btn:hover{ background:var(--ink); color:var(--paper); }
.icon-btn.ghost{ border-color:var(--line); color:var(--ink-soft); }
.icon-btn.ghost:hover{ background:var(--paper-2); color:var(--ink); }
.brand{ font-weight:700; font-size:1.05rem; letter-spacing:-0.01em; text-decoration:none; }

/* ---------- home ---------- */
.hero{ text-align:center; margin:16px 0 26px; }
.hero h1{ font-weight:800; color:var(--ink); font-size:2.4rem; margin:0 0 8px; letter-spacing:-0.015em; line-height:1.05; }
.hero p{ color:var(--ink-soft); font-size:1rem; margin:0 auto; max-width:560px; line-height:1.55; }
.hero .stat-line{ margin-top:12px; font-size:0.8rem; color:var(--ink-faint); font-weight:700; letter-spacing:.04em; text-transform:uppercase; }
.section-title{
  font-size:0.74rem; font-weight:800; letter-spacing:.09em; text-transform:uppercase; color:var(--ink-soft);
  margin:26px 0 10px; display:flex; align-items:center; gap:12px;
}
.section-title::after{ content:''; flex:1; height:1px; background:var(--line); }
.cards{ display:grid; grid-template-columns:repeat(auto-fill,minmax(220px,1fr)); gap:12px; }
.card{
  text-decoration:none;
  background:var(--tile-bg); border:1.5px solid var(--line); border-radius:14px; padding:14px 14px 12px;
  cursor:pointer; text-align:left; display:flex; flex-direction:column; gap:6px; color:var(--ink);
  box-shadow:0 2px 0 var(--tile-shadow); transition:transform .12s, box-shadow .12s, border-color .12s;
  position:relative;
}
.card:hover{ transform:translateY(-2px); box-shadow:0 6px 14px var(--tile-shadow); border-color:var(--ink); }
.card .icon{
  width:46px; height:46px; border-radius:10px; display:flex; align-items:center; justify-content:center;
  font-family:Consolas,'SF Mono',monospace; font-weight:700; font-size:0.95rem; margin-bottom:2px; white-space:nowrap; overflow:hidden; padding:0 4px;
}
.card .icon .katex{ font-size:0.9em; }
.card .icon.c1{ background:var(--accent-1-bg); color:var(--accent-1); }
.card .icon.c2{ background:var(--accent-2-bg); color:var(--accent-2); }
.card .icon.c3{ background:var(--accent-3-bg); color:var(--accent-3); }
.card .icon.c4{ background:var(--accent-4-bg); color:var(--accent-4); }
.card .name{ font-weight:800; color:var(--ink); font-size:1.08rem; letter-spacing:-0.01em; }
.card .blurb{ color:var(--ink-soft); font-size:0.82rem; line-height:1.45; flex:1; }
.card .meta{ display:flex; gap:10px; font-size:0.72rem; color:var(--ink-faint); font-weight:700; margin-top:4px; flex-wrap:wrap; }
.card .meta .daily-done{ color:var(--accent-2); }
.card .tag{ position:absolute; top:12px; right:12px; font-size:0.62rem; font-weight:800; letter-spacing:.06em; text-transform:uppercase; padding:3px 7px; border-radius:20px; background:var(--paper-2); color:var(--ink-soft); border:1px solid var(--line); }

/* ---------- play header ---------- */
.play-head{ text-align:center; margin-bottom:12px; }
.play-head h1{ font-weight:800; color:var(--ink); font-size:1.9rem; margin:0 0 4px; letter-spacing:-0.01em; }
.play-head .tagline{ color:var(--ink-soft); font-size:0.92rem; margin:0 0 10px; line-height:1.5; }
.rules{ font-size:0.8rem; color:var(--ink-soft); background:var(--paper-2); border:1px solid var(--line); border-radius:10px; padding:9px 13px; text-align:left; line-height:1.55; }
.rules b{ color:var(--ink); }
.rules summary{ cursor:pointer; font-weight:700; color:var(--ink); }
.options{ display:flex; flex-wrap:wrap; gap:8px; justify-content:center; align-items:center; margin:12px 0 6px; }
.seg{ display:inline-flex; border:1.5px solid var(--ink); border-radius:20px; overflow:hidden; }
.seg button{
  background:none; border:0; color:var(--ink); padding:6px 12px; font-weight:700; font-size:0.78rem; cursor:pointer;
  border-right:1.5px solid var(--ink);
}
.seg button:last-child{ border-right:0; }
.seg button.on{ background:var(--ink); color:var(--paper); }
.seed-tag{ font-family:Consolas,'SF Mono',monospace; font-size:0.74rem; color:var(--ink-faint); }
.seed-tag input{ font:inherit; width:7.5ch; border:1px solid var(--line); background:var(--tile-bg); color:var(--ink); border-radius:6px; padding:2px 5px; }

.status-row{ display:flex; align-items:center; justify-content:space-between; margin:14px 0 12px; gap:10px; }
.mistakes-label{ font-size:0.74rem; color:var(--ink-soft); font-weight:700; text-transform:uppercase; letter-spacing:.04em; }
.dots{ display:flex; gap:6px; margin-top:4px; }
.dot{ width:11px; height:11px; border-radius:50%; background:var(--ink); opacity:0.85; transition:all .25s; }
.dot.used{ background:transparent; border:2px solid var(--danger); opacity:1; }
.timer{ font-family:Consolas,'SF Mono',monospace; font-weight:600; font-size:0.85rem; color:var(--ink-soft); }
.preamble{ text-align:center; font-size:1rem; margin:0 0 10px; padding:8px 12px; background:var(--paper-2); border:1px dashed var(--line); border-radius:10px; }

/* ---------- solved cards ---------- */
.solved-stack{ display:flex; flex-direction:column; gap:8px; margin-bottom:10px; }
.solved-card{
  border-radius:12px; padding:11px 14px; display:flex; flex-direction:column; gap:4px;
  animation:dropIn .35s cubic-bezier(.2,.9,.3,1.2); border:1.5px solid transparent;
}
@keyframes dropIn{ from{ opacity:0; transform:translateY(-10px) scale(.97);} to{ opacity:1; transform:none; } }
.solved-card .tier-label{ font-size:0.66rem; font-weight:800; text-transform:uppercase; letter-spacing:.06em; opacity:.85; display:flex; justify-content:space-between; align-items:center; gap:8px; }
.solved-card .tier-label .toggle{ background:none; border:1px solid currentColor; color:inherit; border-radius:12px; padding:2px 8px; font-size:0.62rem; font-weight:800; cursor:pointer; letter-spacing:.04em; text-transform:uppercase; }
.solved-card .glabel{ font-size:1.05rem; font-weight:700; color:var(--ink); line-height:1.35; }
.solved-card .members{ display:flex; flex-wrap:wrap; gap:6px 10px; font-size:0.9rem; color:var(--ink); }
.solved-card .members > span{ background:rgba(255,255,255,0.45); border-radius:8px; padding:3px 8px; }
:root[data-theme="dark"] .solved-card .members > span{ background:rgba(0,0,0,0.25); }
@media (prefers-color-scheme: dark){ :root:not([data-theme="light"]) .solved-card .members > span{ background:rgba(0,0,0,0.25); } }
.solved-card .working{ margin-top:4px; padding-top:6px; border-top:1px dashed currentColor; font-size:0.85rem; color:var(--ink); display:grid; grid-template-columns:auto 1fr; gap:3px 12px; align-items:baseline; }
.solved-card .working .w-tile{ opacity:.8; }
.solved-card .working .w-explain{ grid-column:1 / -1; padding-top:4px; font-size:0.84rem; color:var(--ink-soft); }
.solved-card.revealed{ opacity:0.7; border:1.5px dashed currentColor; }
.tier-1{ background:var(--accent-1-bg); color:var(--accent-1); }
.tier-2{ background:var(--accent-2-bg); color:var(--accent-2); }
.tier-3{ background:var(--accent-3-bg); color:var(--accent-3); }
.tier-4{ background:var(--accent-4-bg); color:var(--accent-4); }

.feedback{ text-align:center; font-weight:700; font-size:0.88rem; min-height:22px; margin:4px 0 8px; }
.feedback.good{ color:var(--accent-2); } .feedback.bad{ color:var(--danger); } .feedback.neutral{ color:var(--ink-soft); }
.hintbox{ text-align:center; font-size:0.85rem; margin:0 0 10px; padding:8px 12px; border-radius:10px; border:1.5px dashed var(--line); color:var(--ink-soft); }
.hintbox b{ color:var(--ink); }

/* ---------- grid ---------- */
.grid{ display:grid; grid-template-columns:repeat(4,1fr); gap:8px; margin-bottom:14px; }
.tile{
  aspect-ratio:1.25/1; background:var(--tile-bg); border:2px solid var(--tile-border); border-radius:12px;
  display:flex; align-items:center; justify-content:center; text-align:center;
  font-weight:700; font-size:1.25rem; line-height:1.2; color:var(--text);
  cursor:pointer; user-select:none; box-shadow:0 2px 0 var(--tile-shadow); padding:18px 6px 6px; overflow:hidden;
  transition:transform .12s, background .15s, color .15s, box-shadow .12s; position:relative;
}
.tile .inner{ max-width:100%; }
.tile .katex{ font-size:1.05em; white-space:normal; }
.tile .inner.one-line .katex{ white-space:nowrap; }
.tile.txt .prose{ display:block; white-space:normal; }
.prose .nw{ white-space:nowrap; display:inline-block; }
.tile.txt .prose .katex{ font-size:1.15em; }
.solved-card .prose{ white-space:normal; }
.tile.txt{ font-weight:800; font-size:1.05rem; line-height:1.3; }
/* Roman Numerals: the numerals in serif capitals (tiles and the working) */
.rn{ font-family:Georgia,'Times New Roman',serif; font-weight:700; letter-spacing:.07em; white-space:nowrap; }
.tile .rn{ font-size:1.35em; }
.tile .key{ position:absolute; top:3px; left:6px; font-size:0.58rem; font-weight:800; color:var(--ink-faint); font-family:Consolas,'SF Mono',monospace; opacity:0; transition:opacity .15s; }
body.show-keys .tile .key{ opacity:1; }
.tile:hover{ transform:translateY(-1px); box-shadow:0 4px 8px var(--tile-shadow); }
.tile:active{ transform:translateY(1px); box-shadow:0 1px 0 var(--tile-shadow); }
.tile.selected{ background:var(--ink); color:#fff; border-color:var(--ink); }
:root[data-theme="dark"] .tile.selected{ color:#0d1424; }
.tile.selected .key{ color:var(--paper); }
.tile.shake{ animation:shake .4s; }
@keyframes shake{ 10%,90%{transform:translateX(-1px);} 20%,80%{transform:translateX(2px);} 30%,50%,70%{transform:translateX(-4px);} 40%,60%{transform:translateX(4px);} }
.tile.pulse-good{ animation:pulseGood .5s; }
@keyframes pulseGood{ 0%{transform:scale(1);} 40%{transform:scale(1.08);} 100%{transform:scale(1);} }
.tile.hint-1{ background:var(--accent-1-bg); border-color:var(--accent-1); }
.tile.hint-2{ background:var(--accent-2-bg); border-color:var(--accent-2); }
.tile.hint-3{ background:var(--accent-3-bg); border-color:var(--accent-3); }
.tile.hint-4{ background:var(--accent-4-bg); border-color:var(--accent-4); }

.controls{ display:flex; gap:8px; justify-content:center; margin-bottom:6px; flex-wrap:wrap; }
.ctrl-btn{
  font-weight:700; font-size:0.88rem; padding:10px 16px; border-radius:10px; cursor:pointer;
  border:1.5px solid var(--ink); background:none; color:var(--ink); transition:background .15s,color .15s,opacity .15s;
}
.ctrl-btn:hover:not(:disabled){ background:var(--ink); color:var(--paper); }
.ctrl-btn:disabled{ opacity:0.35; cursor:default; }
.ctrl-btn.primary{ background:var(--ink); color:var(--paper); }
.ctrl-btn.primary:hover:not(:disabled){ opacity:0.85; }
.ctrl-btn.primary:disabled{ opacity:0.3; }

.end-panel{ text-align:center; padding:22px 18px; border-radius:14px; background:var(--paper-2); border:1px solid var(--line); margin-bottom:16px; }
.end-panel .headline{ font-weight:700; font-size:1.5rem; margin:0 0 6px; }
.end-panel .sub{ color:var(--ink-soft); font-size:0.9rem; margin:0 0 14px; line-height:1.5; }
.end-panel .share-grid{ font-size:1.1rem; line-height:1.25; letter-spacing:2px; margin:0 0 14px; font-family:Consolas,'SF Mono',monospace; white-space:pre; }
.end-panel .btns{ display:flex; gap:8px; justify-content:center; flex-wrap:wrap; }

footer{ text-align:center; color:var(--ink-faint); font-size:0.74rem; margin-top:22px; line-height:1.6; }
footer .keys{ font-family:Consolas,'SF Mono',monospace; }

/* ---------- stats ---------- */
.stats-table{ width:100%; border-collapse:collapse; font-size:0.84rem; margin-top:10px; }
.stats-table th, .stats-table td{ text-align:left; padding:7px 8px; border-bottom:1px solid var(--line); }
.stats-table th{ font-size:0.68rem; text-transform:uppercase; letter-spacing:.06em; color:var(--ink-soft); }
.stats-table td.num{ font-family:Consolas,'SF Mono',monospace; text-align:right; }
.stats-table th.num{ text-align:right; }

.toast{ position:fixed; left:50%; bottom:24px; transform:translateX(-50%) translateY(20px); background:var(--ink); color:var(--paper); padding:10px 16px; border-radius:20px; font-weight:700; font-size:0.84rem; opacity:0; transition:all .25s; pointer-events:none; z-index:50; }
.toast.on{ opacity:1; transform:translateX(-50%) translateY(0); }

@media (max-width:420px){
  .play-head h1{ font-size:1.6rem; }
  .hero h1{ font-size:2rem; }
  .tile{ font-size:1rem; border-radius:10px; }
  .grid{ gap:6px; }
  .ctrl-btn{ padding:9px 12px; font-size:0.78rem; }
}

/* ---------- tile letters (A–P stay with each tile) ---------- */
.tile .letter{ position:absolute; top:4px; left:7px; font-size:0.62rem; font-weight:800; color:var(--ink-faint); letter-spacing:.02em; }
.tile.selected .letter{ color:rgba(255,255,255,.75); }
.tile .key{ left:auto; right:7px; }
.solved-card .m-letter{ font-size:0.68rem; font-weight:800; margin-right:6px; opacity:.75; }

/* ---------- answers (teacher's screen only) ---------- */
.ans-toggle{ display:inline-flex; align-items:center; gap:6px; font-size:0.8rem; font-weight:700; color:var(--ink); cursor:pointer; }
.ans-toggle input{ width:15px; height:15px; margin:0; accent-color:var(--ink); }
.icon-btn.present{ background:var(--ink); color:#fff; border-color:var(--ink); }
.icon-btn.present:hover{ opacity:.88; background:var(--ink); color:#fff; }
.tile.ans-1{ box-shadow:inset 0 -7px 0 var(--accent-1); } .tile.ans-2{ box-shadow:inset 0 -7px 0 var(--accent-2); }
.tile.ans-3{ box-shadow:inset 0 -7px 0 var(--accent-3); } .tile.ans-4{ box-shadow:inset 0 -7px 0 var(--accent-4); }
.answer-key{ margin:6px 0 16px; padding:12px 14px; border-radius:12px; background:var(--tile-bg); border:1.5px dashed var(--line); }
.answer-key .ak-title{ font-size:0.7rem; font-weight:800; text-transform:uppercase; letter-spacing:.06em; color:var(--ink-soft); margin-bottom:6px; }
.answer-key .ak-row{ display:flex; align-items:baseline; gap:12px; padding:6px 10px; border-radius:8px; margin-top:5px; }
.answer-key .ak-row.done{ opacity:.55; }
.answer-key .ak-letters{ font-family:Consolas,'SF Mono',monospace; font-weight:800; white-space:nowrap; }
.answer-key .ak-label{ color:var(--text); font-weight:600; }

/* ---------- the display on a second screen ---------- */
.display-howto{ margin:10px 0 6px; padding:12px 14px; border-radius:12px; background:var(--tile-bg); border:1.5px solid var(--line);
  font-size:1rem; line-height:1.5; color:var(--ink); text-align:left; }
.display-howto b{ display:block; font-size:.75rem; text-transform:uppercase; letter-spacing:.06em; color:var(--ink-faint); margin-bottom:4px; }
body.display-mode .options, body.display-mode .rules, body.display-mode footer, body.display-mode .topbar,
body.display-mode .answer-key, body.display-mode .end-panel .btns{ display:none !important; }

body.display-mode{ padding-block:10px 20px; }
body.display-mode .play-head .tagline{ display:none; }
body.display-mode .tile{ font-size:1.7rem; }
body.display-mode .tile .letter{ font-size:0.95rem; top:6px; left:10px; }
.go-full{ position:fixed; inset:0; z-index:100; display:flex; align-items:center; justify-content:center; background:rgba(0,20,60,.55); cursor:pointer; }
.go-full > div{ background:#fff; color:#002060; border-radius:14px; padding:22px 26px; text-align:center; display:flex; flex-direction:column; gap:8px; box-shadow:0 20px 60px rgba(0,0,0,.35); }
.go-full strong{ font-size:1.3rem; } .go-full span{ font-size:.9rem; color:#5a6478; }
.go-full button{ font:inherit; border:0; background:none; color:#002060; text-decoration:underline; cursor:pointer; padding:0; }

/* ---------- play screen: name, description and options beside the tiles ---------- */
.wrap.play{ max-width:1500px; display:grid; grid-template-columns:minmax(250px, 340px) auto; justify-content:center; align-items:start; gap:10px 32px; }
/* the tiles are sized to the window's height so the whole board fits on one screen */
.play-main{ width:min(100%, 980px, calc((100vh - 240px) * 1.25)); min-width:340px; }
.play-side .topbar{ margin-bottom:10px; }
.play-side .play-head{ text-align:left; }
.play-side .play-head h1{ font-size:1.7rem; line-height:1.15; }
.play-side .options{ justify-content:flex-start; }
.play-side footer{ text-align:left; margin-top:14px; }
.play-side .answer-key{ margin-top:12px; }
.play-main .status-row{ margin-top:0; }
@media (max-width:900px){
  .wrap.play{ grid-template-columns:minmax(0, 1fr); max-width:620px; }
  .play-main{ width:100%; min-width:0; }
  .play-side .play-head{ text-align:center; }
  .play-side .options{ justify-content:center; }
}
body.display-mode .wrap.play{ grid-template-columns:minmax(0, 1fr); max-width:none; justify-items:center; }
body.display-mode .play-side{ text-align:center; }
body.display-mode .play-side .play-head{ text-align:center; margin-bottom:4px; }
body.display-mode .play-main{ width:min(96vw, calc((100vh - 300px) * 1.25)); min-width:0; }
/* on a wide display: the name and how to play at the side, the tiles as big as the height allows */
@media (min-width:1000px){
  body.display-mode .wrap.play{ grid-template-columns:minmax(240px, 320px) auto; justify-content:center; justify-items:stretch; align-items:center; min-height:calc(100vh - 90px); }
  body.display-mode .play-side{ text-align:left; }
  body.display-mode .play-side .play-head{ text-align:left; }
  body.display-mode .display-howto{ font-size:1.15rem; }
  body.display-mode .play-main{ width:min(calc(100vw - 420px), calc((100vh - 250px) * 1.25)); }
}

/* the drop-down for moving to another puzzle, under the puzzle's name */
.mode-pick{ box-sizing:border-box; width:100%; display:flex; align-items:center; gap:8px; margin:2px 0 8px; font-size:.74rem; font-weight:800; letter-spacing:.08em; text-transform:uppercase; color:var(--ink-soft); }
.mode-pick select{ box-sizing:border-box; flex:1 1 0; min-width:0; font:inherit; font-size:.95rem; font-weight:700; letter-spacing:0; text-transform:none; height:38px; padding:0 8px; border-radius:9px; border:1.5px solid var(--line); background:var(--tile-bg); color:var(--ink); }
body.display-mode .mode-pick{ display:none; }