* { -webkit-tap-highlight-color:transparent; touch-action:manipulation; }
.main-content { min-height:calc(100vh - 160px); padding:clamp(20px,4vw,40px) 12px 48px; background:#fff; }
[data-theme="dark"] .main-content { background:linear-gradient(180deg,rgba(9,15,22,.96),rgba(5,10,16,.92)); }
.mod-container { max-width:900px; margin:0 auto; }
.mod-card {
    background:#fff; border-radius:36px;
    padding:clamp(18px,2.5vw,36px);
    box-shadow:0 10px 24px rgba(15,23,42,.08);
    border:1px solid rgba(148,163,184,.22);
    position:relative; overflow:hidden;
}
[data-theme="dark"] .mod-card {
    background:linear-gradient(155deg,rgba(10,31,47,.97),rgba(5,16,25,.98) 58%,rgba(8,27,40,.97)),#0b1d2b;
    box-shadow:0 20px 48px rgba(0,0,0,.32); border-color:rgba(94,188,245,.24);
}
.mod-card::before {
    content:""; position:absolute; inset:0; pointer-events:none;
    background:radial-gradient(circle at top right,rgba(255,194,92,.12),transparent 24%),
               radial-gradient(circle at top left,rgba(74,219,255,.12),transparent 24%);
}
.mod-title {
    font-weight:800; font-size:clamp(1.4rem,3.8vw,2.4rem);
    background:linear-gradient(145deg,#0f5fd0,#00a7d8 48%,#f97316);
    -webkit-background-clip:text; background-clip:text; -webkit-text-fill-color:transparent;
    margin:0 0 4px; line-height:1.1; text-align:center;
}
[data-theme="dark"] .mod-title {
    background:linear-gradient(145deg,#f8fdff,#7bd7ff 48%,#ffd27a);
    -webkit-background-clip:text; background-clip:text; -webkit-text-fill-color:transparent;
}
.mod-sub { text-align:center; color:#87bfdb; font-size:.85rem; letter-spacing:.16em; text-transform:uppercase; margin:0 0 22px; }
.puzzle-meta { display:flex; justify-content:space-between; align-items:center; margin-bottom:16px; flex-wrap:wrap; gap:8px; }
.meta-chip {
    background:linear-gradient(180deg,rgba(14,42,60,.96),rgba(8,28,42,.96));
    padding:8px 16px; border-radius:100px; border:1px solid rgba(98,177,223,.38);
    color:#ceecff; font-size:.8rem; font-weight:600; letter-spacing:.05em;
}
.meta-chip span { color:#fff7b5; font-weight:800; margin-left:4px; }
/* Puzzle card */
.puzzle-shell {
    background:linear-gradient(180deg,rgba(7,24,36,.92),rgba(7,24,36,.74));
    border:1px solid rgba(95,179,228,.22); border-radius:26px;
    padding:clamp(18px,3vw,28px); margin-bottom:18px; position:relative;
}
.puzzle-category {
    display:inline-block; font-size:.7rem; letter-spacing:.18em; text-transform:uppercase;
    background:rgba(74,219,255,.12); border:1px solid rgba(74,219,255,.3);
    color:#4adbff; padding:4px 14px; border-radius:30px; margin-bottom:14px;
}
.puzzle-q {
    font-size:clamp(1rem,3vw,1.25rem); font-weight:600; color:#eef8ff;
    line-height:1.65; margin-bottom:18px;
}
/* Diagram area */
.puzzle-diagram {
    background:rgba(0,0,0,.25); border-radius:14px; padding:14px;
    margin-bottom:18px; font-family:'Courier New',monospace;
    font-size:clamp(.72rem,2vw,.88rem); color:#7bd7ff;
    line-height:1.7; white-space:pre; overflow-x:auto;
    display:none;
}
/* Answer options */
.options-grid { display:grid; grid-template-columns:1fr 1fr; gap:10px; }
@media(max-width:480px) { .options-grid { grid-template-columns:1fr; } }
.option-btn {
    background:rgba(255,255,255,.04); border:1.5px solid rgba(255,255,255,.1);
    border-radius:16px; padding:14px 16px; text-align:left;
    color:#cbeeff; font-size:clamp(.84rem,2.5vw,.97rem); font-weight:500;
    cursor:pointer; transition:.12s; line-height:1.4;
}
.option-btn:hover { background:rgba(74,219,255,.1); border-color:rgba(74,219,255,.4); color:#fff; }
.option-btn.selected-correct { background:rgba(74,255,181,.14); border-color:#4affb5; color:#c0fff0; }
.option-btn.selected-wrong   { background:rgba(255,60,60,.12); border-color:#ff4444; color:#ffc0c0; }
.option-btn.reveal-correct   { background:rgba(74,255,181,.08); border-color:rgba(74,255,181,.5); color:#c0fff0; }
.option-btn:disabled { cursor:default; }
/* Explanation */
.explanation {
    background:rgba(74,219,255,.06); border:1px solid rgba(74,219,255,.2);
    border-radius:14px; padding:14px 16px; color:#cbeeff;
    font-size:.88rem; line-height:1.6; margin-top:14px; display:none;
}
.explanation strong { color:#7bd7ff; }
/* Navigation */
.nav-row { display:flex; justify-content:space-between; align-items:center; gap:10px; flex-wrap:wrap; }
.btn-nav {
    background:linear-gradient(180deg,rgba(14,42,60,.96),rgba(8,28,42,.96));
    border:1px solid rgba(98,177,223,.38); border-radius:60px;
    color:#ceecff; font-size:.92rem; font-weight:700; padding:11px 22px;
    cursor:pointer; transition:.08s; user-select:none;
}
.btn-nav:hover { border-color:#4adbff; color:#fff; }
.btn-primary {
    background:linear-gradient(160deg,#ffae5a,#f57c2e); border:none;
    font-size:clamp(.9rem,3vw,1.1rem); font-weight:700; padding:12px 24px;
    border-radius:60px; color:#0e2b37; letter-spacing:1px;
    box-shadow:0 6px 0 #a1440b,0 6px 20px #ffb45b; cursor:pointer;
    transition:.08s; user-select:none;
}
.btn-primary:active { transform:translateY(5px); box-shadow:0 1px 0 #a1440b; }
.progress-dots { display:flex; gap:6px; align-items:center; flex-wrap:wrap; justify-content:center; }
.dot {
    width:10px; height:10px; border-radius:50%;
    background:rgba(15,23,42,.26);
    border:1px solid rgba(15,23,42,.18);
    transition:.2s;
}
[data-theme="dark"] .dot {
    background:rgba(255,255,255,.18);
    border-color:rgba(255,255,255,.06);
}
.dot.done-ok  { background:#4affb5; border-color:#4affb5; box-shadow:0 0 8px #4affb5; }
.dot.done-err { background:#ff5555; border-color:#ff5555; box-shadow:0 0 8px #ff5555; }
.dot.current  { background:#fff7b5; border-color:#facc15; box-shadow:0 0 10px rgba(255,191,0,.85); transform:scale(1.35); }