.flash-app{width:min(980px,calc(100% - 24px));min-height:100dvh;margin:0 auto;padding:14px 0 calc(120px + env(safe-area-inset-bottom))}.flash-top{display:flex;justify-content:space-between;gap:14px;align-items:flex-start;padding:12px 0}.flash-top h1{margin:0;font-size:clamp(27px,5vw,46px);line-height:1.08;letter-spacing:0}.flash-top p{margin:0;color:var(--muted)}.kicker{width:fit-content;margin-bottom:5px;padding:3px 9px;border-radius:999px;background:#fff3c4;color:#76520c;font-size:12px;font-weight:900}.top-actions{display:grid;justify-items:end;gap:8px}.score-chip{min-height:36px;padding:6px 11px;border:1px solid #f1cf64;border-bottom-width:3px;border-radius:999px;background:#fff8db;color:#805b0d;font-size:14px;font-weight:950;line-height:1.35}.flash-controls button{border:1px solid var(--line);border-bottom-width:3px;border-radius:8px;background:#fff;color:var(--ink);font:inherit;font-weight:900;cursor:pointer;touch-action:manipulation}.study-meter{display:grid;grid-template-columns:1fr auto;gap:10px 14px;align-items:center;padding:12px;border:1px solid #d4e7df;border-bottom-width:4px;border-radius:8px;background:#fff;box-shadow:0 10px 24px #18201d0f}.study-meter div:not(.flash-progress){display:grid;gap:1px}.study-meter span,.stat-box span{color:var(--muted);font-size:12px;font-weight:900;line-height:1.25}.study-meter strong{font-size:clamp(20px,4vw,30px);line-height:1.05}.flash-progress{grid-column:1 / -1;height:13px;overflow:hidden;border-radius:999px;background:#dce5df}.flash-progress span{display:block;width:0;height:100%;background:linear-gradient(90deg,#1fc28b,#2f80ed 52%,#ffb84d);transition:width .2s ease}.progress-stats{display:grid;grid-template-columns:repeat(4,minmax(0,1fr));gap:10px;padding:12px 0 2px}.stat-box{min-width:0;padding:12px;border:1px solid var(--line);border-bottom-width:3px;border-radius:8px;background:#fff}.stat-box strong{display:block;margin-top:3px;overflow:hidden;font-size:clamp(18px,3vw,26px);line-height:1.15;text-overflow:ellipsis;white-space:nowrap}.chips{display:flex;gap:8px;overflow-x:auto;padding:12px 0;scrollbar-width:none}.chips::-webkit-scrollbar{display:none}.mode-chips{display:grid;grid-template-columns:repeat(3,minmax(0,1fr));gap:8px;padding:12px 0 0}.mode-chips button,.chips button{flex:0 0 auto;max-width:310px;min-height:42px;padding:8px 12px;overflow:hidden;border:1px solid var(--line);border-bottom-width:3px;border-radius:999px;background:#fff;color:var(--muted);text-align:left;text-overflow:ellipsis;white-space:nowrap;font:inherit;font-size:14px;font-weight:900;cursor:pointer}.mode-chips button{max-width:none;text-align:center}.mode-chips button.active{border-color:#2f80ed;background:#e7f0ff;color:#22528f}.chips button.active{border-color:#1d8c78;background:#dff7ee;color:#0d5a4c}.flash-card{display:block;padding:0;perspective:1400px;background:transparent}.flip-card{position:relative;min-height:560px;transform-style:preserve-3d;transition:transform .52s cubic-bezier(.2,.72,.18,1)}.flash-card.is-revealed .flip-card{transform:rotateY(180deg)}.card-face{position:relative;display:grid;grid-template-rows:auto minmax(230px,1fr);gap:18px;padding:22px;overflow-x:hidden;overflow-y:auto;min-height:560px;border:1px solid #d5e5dd;border-bottom-width:5px;border-radius:8px;background:linear-gradient(180deg,#fffffff5,#ffffffe6),radial-gradient(circle at 12% 0,rgba(255,209,102,.24),transparent 32%),radial-gradient(circle at 100% 18%,rgba(47,128,237,.16),transparent 34%);box-shadow:0 18px 40px #18201d1f;backface-visibility:hidden}.card-front{min-height:560px}.card-back{position:absolute;inset:0;min-height:560px;transform:rotateY(180deg);background:linear-gradient(180deg,#ecfaf3fa,#ffffffeb),radial-gradient(circle at 10% 8%,rgba(31,194,139,.24),transparent 34%),radial-gradient(circle at 96% 20%,rgba(255,184,77,.24),transparent 32%)}.flash-question h2,.answer-face h2{margin:0 0 10px;font-size:clamp(25px,4vw,42px);line-height:1.25;letter-spacing:0}.flash-question p,.answer-face p.meta{width:fit-content;margin:0 0 8px;padding:4px 10px;border-radius:999px;background:#e7f4ff;color:#22528f;font-size:13px;font-weight:900}.flash-images{display:grid;place-items:center;gap:12px;min-height:230px;padding:12px;border:1px dashed #b9d7cc;border-radius:8px;background:#f4fbf7}.card-back .flash-images{background:#ffffff94}.flash-images img{max-width:100%;max-height:350px;object-fit:contain;border:1px solid var(--line);border-bottom-width:4px;border-radius:8px;background:#fff}.flash-watermark{width:min(100%,520px);border-radius:8px}.flash-watermark img{display:block;width:100%}.flash-image-fallback{display:grid;align-content:center;gap:10px;width:min(100%,520px);min-height:220px;padding:22px;border:1px solid #d3bf65;border-bottom-width:4px;border-radius:8px;background:linear-gradient(135deg,#fff8dbf5,#fffffff5),repeating-linear-gradient(0deg,rgba(211,191,101,.12) 0 1px,transparent 1px 26px);color:#24342f;box-shadow:0 12px 28px #18201d14}.flash-image-fallback span{color:#76520c;font-size:13px;font-weight:950;line-height:1.25}.flash-image-fallback strong{font-size:clamp(20px,3vw,30px);line-height:1.34}.answer-text{align-self:center;padding:18px;border:1px solid #bfe4d8;border-left:6px solid #1d8c78;border-radius:8px;background:#fff;font-size:clamp(22px,3.4vw,34px);font-weight:900;line-height:1.45}.flash-controls{position:fixed;right:0;bottom:0;left:0;display:grid;grid-template-columns:52px 1fr 52px auto auto;gap:8px;width:min(760px,calc(100% - 24px));margin:0 auto;padding:12px 0 calc(12px + env(safe-area-inset-bottom));background:#f8f7f2eb;backdrop-filter:blur(10px)}.flash-controls button{min-height:54px;font-size:22px;box-shadow:0 3px #18201d14}.flash-controls button i{font-style:normal}.flash-controls button span{display:none}.flash-controls button:active{transform:translateY(2px);border-bottom-width:1px;box-shadow:none}.flash-controls .primary{border-color:#0f6c5e;background:#16a06f;color:#fff;font-size:18px}.flash-controls button.active{border-color:#e1a52f;background:#fff1c2;color:#6f4c09}.flash-controls button:disabled{opacity:.42;cursor:not-allowed;transform:none}@media(max-width:680px){body:has(.flash-app) .site-header{display:none}.flash-app{min-height:100dvh;padding:14px 0 calc(200px + env(safe-area-inset-bottom))}.flash-top{display:grid;grid-template-columns:minmax(0,1fr);padding:6px 0 10px}.top-actions{justify-items:stretch}.score-chip{text-align:center}.progress-stats{display:none}.mode-chips{padding:10px 0 0;gap:6px}.mode-chips button{min-height:38px;padding:7px 8px;font-size:13px}.chips{padding:10px 0}.chips button{min-height:38px;padding:7px 11px}.flip-card{min-height:420px}.card-face{min-height:420px;grid-template-rows:auto minmax(180px,1fr);gap:14px;padding:16px}.card-front,.card-back{min-height:420px}.flash-question h2,.answer-face h2{font-size:clamp(22px,6vw,34px)}.flash-images{min-height:180px;padding:10px}.flash-images img{max-height:250px}.answer-text{padding:14px;font-size:clamp(20px,5.7vw,28px)}.flash-controls{grid-template-columns:1fr 1fr;gap:6px;padding:8px 0 calc(8px + env(safe-area-inset-bottom))}.flash-controls #revealBtn{grid-column:1 / -1;order:-2}.flash-controls #prevBtn,.flash-controls #nextBtn{order:-1}.flash-controls button{min-height:52px;font-size:22px}.flash-controls button span{display:inline;font-size:14px;font-weight:900;margin-left:6px}.flash-controls .primary{font-size:20px}}@media(prefers-reduced-motion:reduce){.flip-card{transition:none}}