/* Warm cream,midnight blue,lake blue and apricot; gold marks achievement. */
:root{--paper:#f8f5ec;--ink:#172e4e;--muted:#626879;--mint:#b9dfef;--line:#ded8cd;--deep:#162b4a}.topbar .edition{color:#67513a;background:#f0e8dc;border:1px solid #dccfbc;border-radius:99px;padding:6px 12px;letter-spacing:.2px}.language-control select,#language-select,.mobile-back{background:#fffdf7;border-color:#d8d0c3}.intro .eyebrow>span{background:#b96e39}.intro h1 span{color:#356887}.intro .target{background:linear-gradient(transparent 58%,#d8e9f1 58%)}.audience-note{color:#52657b;letter-spacing:.1px}.activity-nav a{color:#3d5470;border-color:#ded8cd;background:#fffdf7;box-shadow:0 3px 9px #172e4e0d}.activity-nav a:hover{background:#e5f0f7;border-color:#84b1c9;box-shadow:0 5px 13px #183f6620}.activity-nav a[aria-current]{background:linear-gradient(135deg,#daeaf4,#d8eaf2);border-color:#7da9c2;color:#274d68;box-shadow:0 0 0 3px #639bbe1a}.activity-nav a.is-completed{color:#385e70;background:#e9f2f6;border-color:#bdd5e3}.activity-nav a.is-completed .orbit-number{color:#385e70}.activity-nav a.is-completed[aria-current]{color:#294f65;background:linear-gradient(135deg,#dcecf4,#d4e7f0);border-color:#739eb6}.activity-nav a.is-completed:hover{color:#294f65;background:#dcecf4;border-color:#87b1c6}.activity-nav a.is-completed::before{color:#2e5e77}.activity-nav a.has-branch-star::after{color:#6b5484}.outer-next{background:#e6eef7;border-color:#a8bfd8;color:#3b5a7f}.outer-next[aria-current]{background:#d3e3f2;border-color:#6c91b9}.outer-next.extreme-link{background:#fae8d8;border-color:#d6b08d;color:#785038!important}.playground{background:linear-gradient(140deg,#162b4a 0%,#1d3e61 65%,#244b67 100%);box-shadow:0 17px 35px -23px #214f7959;border:1px solid #436582}.playground .experiment-label,.playground .board-caption{color:#c8dfef}.playground .experiment-label::before{content:'';display:inline-block;width:6px;height:6px;border-radius:50%;background:#f5c39d;margin-right:7px;vertical-align:1px}.playground .rule-reminder{color:#c6deec}.playground .rules{color:#d1e2ef;border-left-color:#f5c39d}.playground .water{background:linear-gradient(180deg,#8ad9f0,#4fa9cb)}.playground .water-surface{background:#def4fc;opacity:.8}.playground .vessel{border-color:#8ebad1;border-top-color:#cde6f2;background:linear-gradient(125deg,#c3edff14,#cceaff07)}.playground .glass-shine{background:#ffffff24}.playground .vessel.has-water .quantity{color:#14364a}.playground .jug-actions button{background:#cfe8f5;border-color:#95bcd3;color:#284f6a;font-weight:500}.playground .jug-actions button span[aria-hidden]{color:#356c8c}.playground .pour-actions button{background:#f5c39d;border-color:#d9a676;color:#64442f}.primary-button,.branch-button{background:#b9dfef;color:#234d69;border:1px solid #8db8d0}.playground .primary-button{background:#b9dfef;color:#234d69;border-color:#8db8d0}.playground button:hover:not(:disabled){filter:brightness(1.04)}.playground .placement-tabs button[aria-pressed=true]{background:#d1e7f4;border-color:#98bed6;color:#294e70}.hint-button{background:#f0e8dc;border-color:#d8c9b4;color:#67513a}.success,.discovery,.number-result{background:linear-gradient(125deg,#edf3f3,#e0eef7);border-color:#bdd2df;box-shadow:0 7px 22px -18px #32638955}.success-mark{background:#b9dfef;color:#234d69}.next-invite{background:#eef3f7;border-color:#c9d8e5}.branch-card{background:#edf2f7;border-color:#c7d6e4}.branch-evidence{background:#e0eef7;border-color:#b9d2e5}.branch-options button[aria-pressed=true]{background:#dcebf5;border-color:#7199bd;box-shadow:inset 3px 0 #557fa6}.branch-complete{background:#dceaf4;color:#3b5a7f}.success-invitation{background:var(--paper);border-color:#c1cddb;box-shadow:0 20px 70px #182c4e38}.invitation-symbol{background:#c9e4f2;color:#2c5771}.success-invitation .branch-button{background:#b9dfef;color:#234d69;border-color:#8db8d0}.success-invitation .extreme-button{background:#f5c39d;color:#64442f!important;border-color:#d9a676!important}.success-invitation .invitation-later{background:#edf0f7;border-color:#ccd4e2;color:#485b74}.extreme-view textarea{background:#193855;border-color:#6f99b7;color:#f0f2d5}.extreme-view .extreme-visual svg{background:#193550}.extreme-controls button,.extreme-grid button,.extreme-proof button{background:#e5eef5;color:#31546d;border-color:#b3cada}.extreme-view button[aria-pressed=true],.extreme-view button.selected{background:#fae8d8;color:#785038;border-color:#d6b08d}.extreme-grid button.lit{background:#f3d47f;color:#644916}.extreme-grid button.covered{background:#d9e7f0;color:#41637b}.orbit-track ellipse{stroke:#c2c9d3}/* A gold title requires all three completed challenges,not answer exposure. */
.activity-nav a.is-fully-completed{background:linear-gradient(140deg,#fff5d1,#f4dfa9);border-color:#b58b36;color:#765016;box-shadow:0 4px 14px -7px #af7e3a55}.activity-nav a.is-fully-completed .orbit-number{color:#765016}.activity-nav a.is-fully-completed::before,.activity-nav a.is-fully-completed::after{color:#765016}.activity-nav a.is-fully-completed:hover{color:#6d4811;background:linear-gradient(140deg,#fff1bd,#eed397);border-color:#a17829;box-shadow:0 5px 18px -7px #af7e3a65}.activity-nav a.is-fully-completed[aria-current]{background:linear-gradient(140deg,#fff1ba,#efd18a);border-color:#9d762b;color:#684712;box-shadow:0 0 0 3px #d9ac4430,0 5px 18px -7px #af7e3a50}.activity-nav a.is-fully-completed .orbit-crown svg{stroke:#926521;fill:#e8bd52}.activity-nav a.has-hollow-crown .orbit-crown svg{fill:none;stroke:#926521;filter:none}.orbit-stage.all-gold .orbit-track ellipse{stroke:#c79a3e}.brand-bridge:not([data-bridge-theme=gold]){--bridge-ink:#203e59;--bridge-muted:#486076;--bridge-accent:#315f84;--bridge-background:linear-gradient(115deg,#eee4d4 0%,#dbeaf2 70%,#cfe3ee 100%);--bridge-line:#b7c4cd;--bridge-line-hover:#6f91ae}
@media(prefers-reduced-motion:no-preference){.activity-nav a.is-fully-completed{animation:gold-arrival .6s ease-out}@keyframes gold-arrival{from{box-shadow:0 0 0 6px #ddb74635}to{box-shadow:0 4px 14px -7px #af7e3a55}}}


/* Desktop: fresh emerald panels and mint controls against the warm cream canvas. */
@media(min-width:980px){
:root{--ink:#37423c;--muted:#606559;--mint:#d3f3de;--line:#d9dccf;--deep:#2c6a56}
body{background:radial-gradient(ellipse at 48% 42%,#dfe5d880,transparent 58%),radial-gradient(ellipse at 82% 8%,#eddfd580,transparent 35%),var(--paper)}
.orbit-center{background:transparent}
.topbar .edition{color:#675a46;background:#efe9dd;border-color:#d9d0c0}
.language-control select,#language-select{background:#f7f4eb;border-color:#d5d5c7}
.audience-note{color:#626c5e}
.intro h1 span{color:#59624b}
.intro .eyebrow>span{background:#a67954}
.intro .target{background:linear-gradient(transparent 58%,#dfe5d3 58%)}
.activity-nav a:not(.is-fully-completed){color:#4e5e50;background:linear-gradient(140deg,#faf7ee,#f0f1e7);border-color:#d7daca;box-shadow:0 3px 12px -7px #48544618}
.activity-nav a:not(.is-fully-completed):hover{background:#e8eddf;border-color:#a9b69d;box-shadow:0 5px 17px -8px #48544630}
.activity-nav a:not(.is-fully-completed)[aria-current]{color:#3e533d;background:linear-gradient(140deg,#e7eadc,#dbe4d2);border-color:#a0ae93;box-shadow:0 0 0 3px #a7b79518}
.activity-nav a.is-completed:not(.is-fully-completed){background:#e9eee0;border-color:#b7c3a8;color:#435a42}
.activity-nav a.is-completed:not(.is-fully-completed)[aria-current]{background:linear-gradient(140deg,#e1e8d6,#d9e3ce);border-color:#99ac87}
.activity-nav a:not(.is-fully-completed) .orbit-number{color:#53604d}
.activity-nav a.is-completed:not(.is-fully-completed)::before{color:#426047}
.activity-nav a.has-branch-star:not(.is-fully-completed)::after{color:#6d5b78}
.orbit-stage:not(.all-gold) .orbit-track ellipse{stroke:#bac4b0}
.outer-next{background:#e6e9df;border-color:#b1bba7;color:#4a5b46}
.outer-next[aria-current]{background:#dbe4d2;border-color:#9aab8d}
.outer-next.extreme-link{background:#f0dfcf;border-color:#c7b299;color:#795437!important}
.playground{background:linear-gradient(145deg,#2c6a56,#32765a 58%,#357a5e);color:#ffffff;border-color:#4e9c74;box-shadow:0 18px 38px -27px #2c6a5650,inset 0 1px #d9f8e62b}
.playground .experiment-label,.playground .board-caption,.playground .capacity,.playground .pan span,.playground .formula-note,.playground .status-row p,.playground .history-controls,.playground .text-button,.playground .sorting-sequence,.playground .schedule-ruler,.playground .schedule-station{color:#ffffff}
.playground .rules,.playground .rule-reminder{color:#ffffff;border-left-color:#f0c9a1}
.playground .clock-center span,.playground .logic-slot,.playground .logic-slot-number,.playground .schedule-task:not([aria-pressed=true]) span{color:#ffffff}
.playground .sorting-step{fill:#ffffff}
.playground .experiment-label::before{background:#f0c9a1}
.playground .water{background:linear-gradient(180deg,#a0ebc5,#72d8a7)}
.playground .water-surface{background:#e4ffef}
.playground .vessel{border-color:#a3e5c1;border-top-color:#dcf8e6;background:linear-gradient(125deg,#d6ffe91a,#d6ffe908)}
.playground .vessel.has-water .quantity{color:#174633}
.playground .jug-actions button,.playground .primary-button,.primary-button,.branch-button{background:#d3f3de;border-color:#94caaa;color:#174633}
.playground .jug-actions button span[aria-hidden]{color:#275a40}
.playground .pour-actions button{background:#f0c9a1;border-color:#d4a77b;color:#5e3d27}
.playground .placement-tabs button[aria-pressed=true]{background:#d3f3de;border-color:#94caaa;color:#174633}
.hint-button{background:#ede7da;border-color:#d2c6b2;color:#685944}
.success,.discovery,.number-result{background:linear-gradient(125deg,#f0f1e5,#e6eddc);border-color:#c5cfb7;box-shadow:0 7px 22px -18px #4f674a40}
.success-mark,.invitation-symbol{background:#d3f3de;color:#174633}
.next-invite,.branch-card{background:#edf0e5;border-color:#cbd2bd}
.branch-evidence{background:#e5ebdc;border-color:#c0ccb0}
.branch-options button[aria-pressed=true]{background:#dfe7d4;border-color:#9bab8a;box-shadow:inset 3px 0 #8b9d7a}
.branch-complete{background:#dfe7d4;color:#486044}
.success-invitation{background:#f8f5ec;border-color:#c5ceba;box-shadow:0 20px 70px #3947342c}
.success-invitation .branch-button{background:#d3f3de;border-color:#94caaa;color:#174633}
.success-invitation .extreme-button{background:#f0c9a1;color:#5e3d27!important;border-color:#d4a77b!important}
.success-invitation .invitation-later{background:#eeeee5;border-color:#d2d6c7;color:#616d59}
.extreme-view textarea,.number-form input{background:#164934;border-color:#8bceab;color:#ffffff}
.extreme-view .extreme-visual svg{background:#2c6a56}
.extreme-controls button,.extreme-grid button,.extreme-proof button{background:#e3e9dc;color:#42573d;border-color:#b8c5ac}
.extreme-view button[aria-pressed=true],.extreme-view button.selected{background:#f0dfcf;color:#795437;border-color:#c7b299}
.extreme-grid button.covered{background:#dfe7d4;color:#486044}
.brand-bridge:not([data-bridge-theme=gold]){--bridge-ink:#3c4d3c;--bridge-muted:#586651;--bridge-accent:#52694a;--bridge-background:linear-gradient(115deg,#ede6d7,#dfe5d7 70%,#dae2d4);--bridge-line:#bfc8b3;--bridge-line-hover:#8ea17f}
/* Light labels and outlines remain distinct on the brighter green panels. */
.playground .more-options button:not([aria-pressed=true]),.playground .b-outline,.playground .more-proof-button,.playground .bridge-bank-heading,.playground .explore-a-form label,.playground .logic-clues,.playground .logic-clue-state,.playground .probability-axes,.playground .probability-fraction-title,.playground .probability-fraction label,.playground .probability-fraction>span,.playground .sums-totals>div{color:#ffffff}
.playground .status-row{border-top-color:#b6ebcf40}
.playground .quantity{color:#ffffff}
.playground .glass-shine{background:#ffffff36}
.playground button:focus-visible,.playground input:focus-visible,.playground select:focus-visible{outline-color:#f7d19c}
}

/* Use locally available Taiwan Traditional fonts; no remote font dependency. */
html[lang=zh-TW] body{font-family:'Noto Sans TC','PingFang TC','Microsoft JhengHei',system-ui,sans-serif}

.v2-link{display:inline-flex;align-items:center;gap:8px;min-height:40px;padding:8px 14px;border:1px solid #a9c6ae;border-radius:24px;background:#e2efdd;color:#244f3b;font-size:13px;white-space:nowrap;text-decoration:none}.v2-link:hover{background:#d5eacd}.v2-link:focus-visible{outline:3px solid #b46630;outline-offset:4px}
.v2-link>[aria-hidden]{flex-shrink:0}
@media(max-width:640px){.header-tools{flex-wrap:wrap;justify-content:flex-end}.header-tools .language-control{flex-shrink:0}.v2-link{white-space:normal;max-width:100%}.v2-link>[data-i18n]{min-width:0;overflow-wrap:anywhere}}

/* Readable active controls and secondary instructions at every viewport. */
html .orbit-center .playground .coin{color:#fff;background:#245840;font-size:13px;line-height:1.4}
.playground .coin:hover:not(:disabled){background:#1d4936}
.playground .placement-tabs button{font-size:13px}
.orbit-center .rule-reminder,.orbit-center .hint-copy,.orbit-center .quiet-note,.closing-note,.mini-footer{font-size:13px;line-height:1.65}
.playground .experiment-label,.playground .board-caption,.playground .text-button{font-size:12px}
footer{font-size:12px;line-height:1.6;flex-wrap:wrap;gap:12px}
.language-load-error{padding:12px 20px;background:#fff3df;color:#56381d;line-height:1.6}

html .orbit-center .playground .jug-actions button,html .orbit-center .playground .pour-actions button{font-size:13px;line-height:1.4}