:root{
  --depth:0; /* 0..1, set from JS */
  --ink:#eaf7ff; --muted:#a9cfe6; --card:rgba(8,40,66,.62); --line:rgba(160,220,255,.18);
  --accent:#ffb4c8; --accent2:#7fe3ff; --good:#7dffb0; --bad:#ff8a8a;
  --t-plankton:#9be7ff; --t-clever:#ffd36e; --t-schooler:#7dd3fc; --t-rare:#c4a1ff; --t-deep:#ff9f6e; --t-krill:#ffe066;
  --radius:20px;
  font-family:"Fredoka",ui-rounded,"SF Pro Rounded",system-ui,-apple-system,"Segoe UI",Roboto,sans-serif;
}
*{box-sizing:border-box}
html{background:#04121f}
html,body{margin:0;min-height:100%;color:var(--ink)}
body{min-height:100dvh;overflow-x:hidden;-webkit-tap-highlight-color:transparent}
.hidden{display:none!important}

/* ocean background darkens with depth */
.ocean{position:fixed;inset:0;z-index:0;transition:background 1.2s ease;
  background:linear-gradient(180deg,
    hsl(198 75% calc(46% - var(--depth)*36%)) 0%,
    hsl(205 80% calc(28% - var(--depth)*22%)) 45%,
    hsl(220 70% calc(12% - var(--depth)*9%)) 100%);}
.rays{position:absolute;inset:-20% -10% auto;height:70%;opacity:calc(.35 - var(--depth)*.3);
  background:repeating-linear-gradient(100deg,rgba(255,255,255,.10) 0 30px,transparent 30px 90px);filter:blur(14px);
  animation:sway 9s ease-in-out infinite alternate;transform-origin:top}
@keyframes sway{from{transform:skewX(-6deg)}to{transform:skewX(6deg)}}
.bubbles span{position:absolute;bottom:-40px;border-radius:50%;border:1.5px solid rgba(200,240,255,.45);background:rgba(200,240,255,.08);animation:rise linear infinite}
@keyframes rise{to{transform:translate(var(--dx,20px),-115vh);opacity:0}}

main{position:relative;z-index:1;max-width:560px;margin:0 auto;padding:calc(env(safe-area-inset-top) + 18px) 18px calc(env(safe-area-inset-bottom) + 28px) 18px}
body.with-gauge main{padding-right:52px}
.screen{display:flex;flex-direction:column;gap:14px;animation:fadein .35s ease}
@keyframes fadein{from{opacity:0;transform:translateY(8px)}to{opacity:1;transform:none}}

.brand{text-align:center;padding:18px 0 6px}
.brand h1{font-size:2.6rem;margin:.1em 0 .1em;letter-spacing:.5px;text-shadow:0 3px 0 rgba(0,0,0,.25)}
.brand.small h1{font-size:2rem}
.logo{font-size:3.6rem;line-height:1;filter:drop-shadow(0 6px 10px rgba(0,0,0,.35))}
.logo .shrimp{display:inline-block;animation:bob 2.6s ease-in-out infinite}
@keyframes bob{50%{transform:translateY(-8px) rotate(-8deg)}}
.tag{color:var(--muted);margin:0;font-size:1rem}

.card{background:var(--card);border:1px solid var(--line);border-radius:var(--radius);padding:18px;backdrop-filter:blur(10px);-webkit-backdrop-filter:blur(10px);box-shadow:0 10px 30px rgba(0,0,0,.25)}
.card h2{margin:.2em 0 .3em;font-size:1.55rem;line-height:1.2}
.card h3{margin:0 0 10px;font-size:1.1rem;color:var(--accent2);display:flex;align-items:center;gap:8px}
.center{text-align:center}
.lbl{display:block;font-size:.95rem;color:var(--muted);margin:2px 0 8px}
.muted{color:var(--muted)}
.err{color:var(--bad);min-height:1.2em;margin:8px 0 0;font-size:.95rem}

input{width:100%;font:inherit;font-size:1.2rem;padding:14px 16px;border-radius:14px;border:2px solid var(--line);background:rgba(0,20,35,.55);color:var(--ink);outline:none;transition:border-color .2s}
input:focus{border-color:var(--accent2)}
input::placeholder{color:#7aa6c0}
.btn{font:inherit;font-size:1.1rem;font-weight:600;border:0;border-radius:14px;padding:14px 18px;cursor:pointer;color:var(--ink);background:rgba(255,255,255,.12);margin-top:10px;width:100%;transition:transform .08s,filter .2s}
.btn:active{transform:scale(.97)}
.btn:disabled{filter:grayscale(.6) brightness(.8);cursor:default}
.btn.primary{background:linear-gradient(180deg,#ffc7d6,#ff8fb1);color:#3a0d22;box-shadow:0 6px 0 #c95b80}
.btn.primary:active{box-shadow:0 2px 0 #c95b80;transform:translateY(4px)}
.btn.ghost{background:transparent;border:1px solid var(--line)}
.btn.danger{background:#7a1f2b}
.btn.sticky{position:sticky;bottom:calc(env(safe-area-inset-bottom) + 10px)}

.rules summary{cursor:pointer;font-weight:600;color:var(--accent2)}
.rules ol{padding-left:1.2em;margin:10px 0;line-height:1.45}
.tiers{display:grid;grid-template-columns:1fr 1fr;gap:6px;margin-top:8px}
.tier-chip{display:flex;justify-content:space-between;gap:6px;padding:6px 10px;border-radius:10px;background:rgba(255,255,255,.06);font-size:.92rem}
.tier-chip b{color:var(--c)}

.hud{display:flex;justify-content:space-between;align-items:center;color:var(--muted);font-weight:500}
.depth-pill{background:rgba(0,0,0,.3);border:1px solid var(--line);padding:4px 12px;border-radius:99px;color:var(--ink)}
.big-emoji{font-size:4rem;margin:6px 0}

.timer{position:relative;width:96px;height:96px;margin:0 auto}
.timer svg{width:100%;height:100%;transform:rotate(-90deg)}
.timer circle{fill:none;stroke-width:9}
.t-bg{stroke:rgba(255,255,255,.12)}
.t-fg{stroke:var(--accent2);stroke-linecap:round;stroke-dasharray:276.46;stroke-dashoffset:0;transition:stroke .3s}
.timer span{position:absolute;inset:0;display:grid;place-items:center;font-size:2rem;font-weight:700}
.timer.low .t-fg{stroke:var(--bad)} .timer.low span{color:var(--bad);animation:pulse .5s ease-in-out infinite alternate}
@keyframes pulse{to{transform:scale(1.12)}}
.prompt{text-align:center}
.prompt-emoji{font-size:2.6rem}
.hint{color:var(--muted);margin:0;font-size:.98rem}
.guess{display:flex;gap:8px}
.guess .btn{width:auto;margin:0;padding:0 22px}
.feedback{text-align:center;min-height:1.6em;margin:2px 0 0;font-size:1.15rem;font-weight:600}
.feedback.miss{color:var(--bad)} .feedback.hit{color:var(--good)}
.shake{animation:shake .35s}
@keyframes shake{20%,60%{transform:translateX(-8px)}40%,80%{transform:translateX(8px)}}
.misses{display:flex;flex-wrap:wrap;gap:6px;justify-content:center}
.misses span{font-size:.85rem;padding:3px 10px;border-radius:99px;background:rgba(255,138,138,.14);color:#ffc0c0;text-decoration:line-through}

.tier-badge{display:inline-flex;align-items:center;gap:10px;padding:10px 18px;border-radius:99px;font-weight:700;font-size:1.25rem;background:rgba(0,0,0,.28);border:2px solid var(--c,var(--line));color:var(--c,var(--ink));animation:pop .5s cubic-bezier(.2,1.6,.4,1)}
@keyframes pop{from{transform:scale(.4);opacity:0}}
.result h2{font-size:1.9rem;margin-top:12px}
.note{color:var(--muted);font-style:italic;margin:.2em 0}
.sink{font-size:1.05rem;margin:.6em 0 0}
.result.gem{background:radial-gradient(circle at 50% 0%,rgba(255,224,102,.35),var(--card) 70%)}
.reveal .tier-row{padding:10px 0;border-top:1px solid var(--line)}
.reveal .tier-row:first-of-type{border-top:0;padding-top:0}
.tier-row .th{display:flex;justify-content:space-between;font-weight:600;color:var(--c)}
.tier-row .th small{color:var(--muted);font-weight:400}
.tier-row .ex{margin-top:4px;line-height:1.5;color:var(--ink)}
.tier-row .ex i{color:var(--muted)}
.tier-row .ex .mine{background:rgba(125,255,176,.18);padding:0 6px;border-radius:6px}

.final-depth{font-size:4rem;font-weight:700;line-height:1;margin:6px 0;text-shadow:0 4px 0 rgba(0,0,0,.3)}
.final-depth small{font-size:1.4rem;color:var(--muted)}
.final-pts{margin:.3em 0;color:var(--muted)} .final-pts b{color:var(--ink)}
.rank{display:inline-block;margin-top:8px;padding:8px 16px;border-radius:99px;font-weight:700;background:rgba(0,0,0,.3);border:2px solid var(--c);color:var(--c)}
table.rounds{width:100%;border-collapse:collapse;font-size:.98rem}
.rounds td{padding:8px 4px;border-top:1px solid var(--line);vertical-align:top}
.rounds tr:first-child td{border-top:0}
.rounds .q{color:var(--muted);font-size:.85rem}
.rounds .pts{text-align:right;white-space:nowrap;font-weight:600}
.board{list-style:none;margin:0;padding:0;display:flex;flex-direction:column;gap:6px}
.board li{display:grid;grid-template-columns:2.2em 1fr auto;align-items:center;gap:8px;padding:10px 12px;border-radius:14px;background:rgba(255,255,255,.06)}
.board li.me{outline:2px solid var(--accent)}
.board .pl{font-weight:700;text-align:center;font-size:1.1rem}
.board .nm{overflow:hidden;text-overflow:ellipsis;white-space:nowrap}
.board .nm small{display:block;color:var(--muted);font-size:.8rem}
.board .sc{text-align:right;font-weight:700} .board .sc small{display:block;color:var(--muted);font-weight:400;font-size:.8rem}
.board .empty{display:block;text-align:center;color:var(--muted)}
.live{color:var(--good);font-size:.8rem;font-weight:500;animation:blink 2s infinite}
@keyframes blink{50%{opacity:.4}}
#s-board .board li{font-size:1.2rem}

/* depth gauge */
.gauge{position:fixed;right:10px;top:50%;transform:translateY(-50%);height:min(62vh,480px);display:flex;gap:4px;z-index:5;pointer-events:none}
.gauge-track{position:relative;width:12px;height:100%;border-radius:99px;background:rgba(255,255,255,.1);border:1px solid var(--line)}
.gauge-fill{position:absolute;left:0;right:0;top:0;height:0;border-radius:99px;background:linear-gradient(180deg,var(--accent2),#5b6cff 60%,#ff8fb1);transition:height 1.2s cubic-bezier(.3,1,.4,1)}
.gauge-diver{position:absolute;left:50%;top:0;transform:translate(-50%,-50%);font-size:20px;transition:top 1.2s cubic-bezier(.3,1,.4,1);filter:drop-shadow(0 2px 3px rgba(0,0,0,.5))}
.gauge-labels{display:none}
@media (min-width:700px){.gauge{right:24px}.gauge-labels{display:flex;flex-direction:column;justify-content:space-between;font-size:.75rem;color:var(--muted)}body.with-gauge main{padding-right:18px}}
@media (prefers-reduced-motion:reduce){*{animation:none!important;transition:none!important}}