:root{color:#20242b;background:#f1f2f4;font-family:Inter,Hiragino Sans,Hiragino Kaku Gothic ProN,Yu Gothic,Meiryo,system-ui,sans-serif;font-synthesis:none;line-height:1.5;text-rendering:optimizeLegibility}*{box-sizing:border-box}body{margin:0;min-width:320px;min-height:100vh}button,a{font:inherit}button{cursor:pointer}button:disabled{cursor:not-allowed}#root{min-height:100vh}.screen{width:min(1060px,100%);min-height:100vh;margin:0 auto;padding:24px 18px}.centered-screen{display:grid;place-content:center;text-align:center}.screen__header,.quiz-header{margin-bottom:24px}.eyebrow,.question-count{margin:0 0 8px;color:#5f6671;font-size:.95rem;font-weight:600}.question-count{font-size:1.35rem;font-weight:800}.quiz-meta{display:flex;flex-wrap:wrap;gap:8px 14px;align-items:center}.difficulty-panel{--difficulty-color: #2f6fed;display:inline-flex;align-items:center;min-height:38px;padding:0 14px;border:1px solid var(--difficulty-color);border-left-width:6px;border-radius:4px;background:#fff;color:var(--difficulty-color);font-size:1.08rem;font-weight:800}.difficulty-panel--basic{--difficulty-color: #11816f}.difficulty-panel--advanced{--difficulty-color: #b78300}.difficulty-panel--extreme{--difficulty-color: #c92828}.difficulty-panel--master{--difficulty-color: #7c3aed}h1,h2,p{overflow-wrap:anywhere}h1{margin:0;color:#171b21;font-size:clamp(1.85rem,4.5vw,3.2rem);line-height:1.12;letter-spacing:0}h2{margin:0 0 12px;font-size:1.2rem}.difficulty-screen .screen__header h1{font-size:1.1rem;line-height:1.4}.difficulty-screen .eyebrow{color:#0f7a6a;font-size:clamp(1.6rem,5vw,2.65rem);font-weight:900}.quiz-header h1:not(.answer-heading){font-size:clamp(1.25rem,3vw,2rem);font-weight:700}.answer-heading{font-size:clamp(1.35rem,3.4vw,2.15rem)}.difficulty-intro{max-width:720px;margin:0 0 10px;color:#334155;font-size:1rem;font-weight:500}.loading-text{color:#757678;font-size:2rem}.difficulty-grid{display:grid;grid-template-columns:repeat(3,minmax(0,1fr));gap:10px;margin-bottom:22px}.difficulty-card{--difficulty-color: #11816f;display:grid;min-height:142px;padding:16px 16px 14px;border:1px solid #cfd5dd;border-left:7px solid var(--difficulty-color);border-radius:4px;background:#fff;color:inherit;text-align:left;transition:background-color .12s ease,border-color .16s ease,box-shadow .16s ease,outline-color .16s ease,transform 80ms ease}.difficulty-card:hover,.difficulty-card.is-selected{border-color:var(--difficulty-color);background:color-mix(in srgb,var(--difficulty-color) 7%,#ffffff);outline:2px solid color-mix(in srgb,var(--difficulty-color) 24%,transparent);outline-offset:-2px}.difficulty-card:active{transform:scale(.985)}.difficulty-card.is-selected{animation:difficulty-select-pulse .34s ease-out both}.difficulty-card--basic{--difficulty-color: #11816f}.difficulty-card--advanced{--difficulty-color: #b78300}.difficulty-card--extreme{--difficulty-color: #b96752}.difficulty-card--master{--difficulty-color: #7c3aed}.difficulty-grid .difficulty-card--master:nth-child(4){grid-column:2}.difficulty-card--master.is-master-reveal{animation:master-card-reveal .22s ease-out both}.difficulty-card__label{color:var(--difficulty-color);font-size:1.3rem;font-weight:800}.difficulty-card__description{color:#515966;font-weight:500}.difficulty-card__eligible-count{align-self:end;color:#515966;font-size:.88rem;font-weight:600}.difficulty-card__count{color:var(--difficulty-color);font-weight:800}.primary-action,.secondary-action{display:inline-flex;align-items:center;justify-content:center;min-height:48px;padding:0 22px;border-radius:5px;text-decoration:none;font-weight:700}.primary-action{border:1px solid #11816f;background:#11816f;color:#fff}.primary-action:disabled{border-color:#c5cad4;background:#c5cad4}.secondary-action{border:1px solid #c5cad4;background:#fff;color:#1d2635}.difficulty-screen>.primary-action{display:flex;width:min(320px,100%);margin:0 auto}.play-screen{display:grid;grid-template-rows:auto auto auto;gap:16px;align-content:start}.play-screen .quiz-header{min-height:clamp(5.7rem,9vw,6.35rem)}.play-screen .quiz-header h1{min-height:1.2em}.choices{display:grid;grid-template-columns:repeat(2,minmax(0,1fr));gap:14px;align-items:start;justify-self:center;width:min(100%,940px)}.video-card{display:grid;grid-template-rows:auto auto auto auto;gap:10px;min-width:0;width:100%;max-width:472px;overflow:hidden;justify-self:center;padding:10px;border:1px solid #cbd2dc;border-top:4px solid #8c96a5;border-radius:4px;background:#fff;color:#20242b;text-align:left;animation:choice-card-enter .18s ease-out both;transition:background-color .14s ease,border-color .14s ease,box-shadow .14s ease,filter .14s ease,transform 80ms ease}.video-card>*{min-width:0;max-width:100%}.video-card:hover:not(:disabled),.video-card.is-selected{border-color:#2f6fed;background:#f8fbff}.video-card:active:not(:disabled){transform:scale(.985)}.video-card.is-correct{border-color:#2f6fed;border-top-color:#2f6fed;background:#f8fbff;outline:3px solid rgba(47,111,237,.16);outline-offset:-3px;animation:choice-card-enter .18s ease-out both,correct-card-pulse .52s ease-out .12s both}.video-card.is-result-reveal{animation:none}.video-card.is-result-reveal.is-correct{animation:correct-card-pulse .52s ease-out .12s both}.video-card.is-dimmed{background:#eceff3;border-color:#c3cad4;border-top-color:#a9b1bd;color:#626b77}.video-card.is-dimmed .video-card__thumb{filter:grayscale(.7);opacity:.72}.video-card__thumb-wrap{width:100%;min-width:0;max-width:100%;aspect-ratio:16 / 9;overflow:hidden;border-radius:3px;background:#dfe4eb}.video-card__thumb{width:100%;height:100%;object-fit:cover}.video-card__thumb--empty{display:grid;place-items:center;color:#5b6472;font-weight:700}.video-card__posted{color:#11816f;font-size:1.16rem;font-weight:800;min-height:1.5em;overflow-wrap:anywhere;word-break:break-word}.video-card__posted.is-hidden{visibility:hidden}.video-card__title{min-height:3.6em;font-size:1.04rem;font-weight:700;overflow-wrap:anywhere;word-break:break-word;line-break:anywhere}.video-card__user{display:flex;align-items:center;gap:8px;color:#5f6671;min-width:0}.video-card__user span{min-width:0;overflow-wrap:anywhere;word-break:break-word}.video-card__icon{width:28px;height:28px;border-radius:50%;object-fit:cover}.timer{display:grid;gap:6px}.timer__label{display:flex;justify-content:space-between;color:#5f6671;font-weight:600}.timer__track{height:12px;overflow:hidden;border-radius:4px;background:#d6dbe3}.timer__bar{width:100%;height:100%;transform-origin:left center;background:#2f6fed;transition:transform 90ms linear}.answer-heading.is-correct,.history-item__meta .is-correct{color:#2f6fed}.answer-heading.is-wrong,.history-item__meta .is-wrong{color:#c92828}.answer-actions{display:grid;grid-template-columns:1fr auto 1fr;align-items:center;gap:12px}.answer-finish{justify-self:start}.answer-next{grid-column:2;min-width:184px;min-height:56px;font-size:1.1rem}.result-actions{display:flex;flex-wrap:wrap;gap:12px;justify-content:flex-start;width:100%}.result-main-actions{display:flex;flex-wrap:wrap;justify-content:center;gap:16px;margin-bottom:24px}.result-main-actions .secondary-action{min-width:180px;min-height:54px;font-size:1.08rem}.result-share-action{order:2;margin-left:auto}.result-score{color:#2f6fed;font-size:clamp(2rem,5vw,3.7rem)}.result-difficulty-line{margin:0 0 12px}.result-average-time{margin:8px 0 0;color:#171b21;font-size:1.15rem;font-weight:800}.history{margin-bottom:24px}.history ol{display:grid;gap:6px;padding:0;list-style:none}.history li{display:grid;gap:12px;padding:12px;border:1px solid #d3d9e2;border-left:5px solid #8c96a5;border-radius:4px;background:#fff;animation:history-item-enter .22s ease-out both}@keyframes choice-card-enter{0%{opacity:0;transform:translateY(10px)}to{opacity:1;transform:translateY(0)}}@keyframes correct-card-pulse{0%{box-shadow:0 0 #2f6fed00}36%{box-shadow:0 0 0 7px #2f6fed2e}to{box-shadow:0 0 #2f6fed00}}@keyframes history-item-enter{0%{opacity:0;transform:translateY(8px)}to{opacity:1;transform:translateY(0)}}@keyframes difficulty-select-pulse{0%{box-shadow:0 0 color-mix(in srgb,var(--difficulty-color) 0%,transparent)}42%{box-shadow:0 0 0 7px color-mix(in srgb,var(--difficulty-color) 22%,transparent)}to{box-shadow:0 0 color-mix(in srgb,var(--difficulty-color) 0%,transparent)}}@keyframes master-card-reveal{0%{opacity:0;transform:translateY(10px) scale(.985)}to{opacity:1;transform:translateY(0) scale(1)}}@media(prefers-reduced-motion:reduce){.difficulty-card,.difficulty-card.is-selected,.difficulty-card--master.is-master-reveal,.video-card,.video-card.is-correct,.history li{animation:none}.difficulty-card,.video-card{transition:none}.difficulty-card:active,.video-card:active:not(:disabled){transform:none}}.history-item__meta{display:flex;flex-wrap:wrap;align-items:center;gap:12px;font-weight:700}.history-item__videos{display:grid;grid-template-columns:repeat(2,minmax(0,1fr));gap:12px}.history-video{display:grid;grid-template-columns:144px minmax(0,1fr);gap:12px;align-items:start;min-width:0}.history-video__thumb-link{display:block;aspect-ratio:16 / 9;overflow:hidden;border-radius:3px;background:#dfe4eb}.history-video__thumb{display:grid;place-items:center;width:100%;height:100%;object-fit:cover;color:#5b6472;font-size:.85rem;font-weight:700}.history-video__body{min-width:0}.history-video__body h3{margin:0 0 6px;font-size:.98rem;line-height:1.35;font-weight:700;overflow-wrap:anywhere}.history-video__title-link{color:#171b21;text-decoration:none;overflow-wrap:anywhere;word-break:break-word;line-break:anywhere}.history-video__title-link:hover{color:#11816f;text-decoration:underline;text-underline-offset:3px}.history-video__body p{margin:0 0 4px;color:#5f6671;font-size:.9rem}.muted,.error-message{color:#5f6671}.error-message{color:#b3261e;font-weight:700}@media(max-width:760px){.screen{padding:24px 14px}.difficulty-grid,.choices,.history-item__videos,.score-board{grid-template-columns:1fr}.difficulty-grid .difficulty-card--master:nth-child(4){grid-column:auto}.choices{width:min(100%,520px)}.video-card{grid-template-columns:clamp(116px,34vw,184px) minmax(0,1fr);grid-template-rows:auto auto auto;column-gap:12px;row-gap:6px;max-width:520px;align-items:start}.video-card__thumb-wrap{grid-row:1 / 4;grid-column:1}.video-card__posted,.video-card__title,.video-card__user{grid-column:2}.video-card__posted{font-size:1rem;min-height:1.5em}.video-card__title{min-height:auto;font-size:.98rem}.video-card__user{font-size:.9rem}.answer-actions{grid-template-columns:1fr 1fr}.answer-next{grid-column:2;width:100%;min-width:0}.history-video{grid-template-columns:clamp(116px,34vw,184px) minmax(0,1fr)}.history-video__body h3{font-size:.95rem}.history-video__body p{font-size:.85rem}}