:root{--bg:#fdf8f3;--surface:#ffffff;--primary:#5ba058;--primary-dark:#47824a;--accent:#ffd54f;--text:#303030;--muted:#a0a0a0;--line:#e9e2d8;--wrong:#d9634e;--card-shadow:0 8px 16px -4px rgba(48,48,48,0.12);--radius:12px}*{box-sizing:border-box}body,html{margin:0;padding:0}body{background:var(--bg);color:var(--text);font-family:Inter,IBM Plex Sans,system-ui,sans-serif;font-size:16px;line-height:1.55;min-height:100vh}.brand,h1,h2,h3{font-family:Nunito Sans,Inter,sans-serif}a{color:var(--primary)}.site-header{background:var(--surface);box-shadow:0 2px 10px rgba(48,48,48,.07);position:-webkit-sticky;position:sticky;top:0;z-index:20}.site-header .inner{max-width:860px;margin:0 auto;padding:14px 20px;display:flex;align-items:center;gap:22px}.brand{font-weight:900;font-size:1.35rem;color:var(--primary);text-decoration:none;position:relative;padding-bottom:2px}.brand .spark{color:var(--text)}.brand:after{content:"";position:absolute;left:0;bottom:-3px;width:58%;height:5px;background:var(--accent);border-radius:99px}.site-nav{display:flex;gap:18px;margin-left:auto;align-items:center}.site-nav a{color:var(--text);text-decoration:none;font-weight:600;font-size:.95rem;padding-bottom:3px}.site-nav a:hover{box-shadow:inset 0 -5px 0 var(--accent)}.user-chip{color:var(--muted);font-size:.9rem}.logout-btn{background:none;border:1px solid var(--line);border-radius:8px;padding:5px 12px;cursor:pointer;font-family:inherit;font-size:.85rem;color:var(--muted)}.logout-btn:hover{border-color:var(--muted);color:var(--text)}.shell{max-width:860px;margin:0 auto;padding:36px 20px 80px}.page-title{font-size:1.9rem;font-weight:900;margin:0 0 6px}.page-sub{color:var(--muted);margin:0 0 28px}.panel{background:var(--surface);border-radius:var(--radius);box-shadow:var(--card-shadow);padding:28px;position:relative}.panel:after{content:"";position:absolute;left:16px;right:16px;bottom:7px;height:0;border-bottom:2px dashed var(--line)}label.field-label{display:block;font-weight:700;font-size:.92rem;margin:18px 0 6px}input[type=password],input[type=text],select{width:100%;padding:11px 13px;border:1.5px solid var(--line);border-radius:9px;font-family:inherit;font-size:1rem;background:var(--surface);color:var(--text)}input:focus,select:focus{outline:none;border-color:var(--accent);box-shadow:0 0 0 3px rgba(255,213,79,.35)}.btn{display:inline-block;background:var(--primary);color:#fff;border:none;border-radius:10px;padding:12px 26px;font-family:Nunito Sans,sans-serif;font-weight:800;font-size:1rem;cursor:pointer;transition:background .15s,box-shadow .15s,transform .1s;text-decoration:none}.btn:hover{background:var(--primary-dark);box-shadow:0 6px 14px -4px rgba(91,160,88,.55)}.btn:active{transform:translateY(1px)}.btn:disabled{background:var(--muted);cursor:wait;box-shadow:none}.btn.secondary{background:var(--surface);color:var(--text);border:1.5px solid var(--line)}.btn.secondary:hover{border-color:var(--muted);box-shadow:none;background:var(--bg)}.error-note{background:#fdeeea;color:#a4402f;border-radius:9px;padding:10px 14px;margin:14px 0 0;font-size:.93rem}.toggle-row{display:flex;align-items:center;gap:10px;margin-top:20px;-webkit-user-select:none;-moz-user-select:none;user-select:none}.toggle-row input{width:20px;height:20px;accent-color:var(--primary)}.study-wrap{perspective:1400px;margin-top:8px}.flipcard{position:relative;transform-style:preserve-3d;transition:transform .6s cubic-bezier(.4,.1,.2,1);min-height:380px}.flipcard.flipped{transform:rotateY(180deg)}.card-face{position:absolute;inset:0;backface-visibility:hidden;-webkit-backface-visibility:hidden;background:var(--surface);border-radius:var(--radius);box-shadow:var(--card-shadow);padding:30px 30px 30px 56px;overflow-y:auto}.card-face.back{transform:rotateY(180deg);background:repeating-linear-gradient(to bottom,transparent 0,transparent 27px,rgba(91,160,88,.14) 28px),var(--surface)}.card-face:before{content:"";position:absolute;top:0;bottom:0;left:34px;border-left:2px dashed var(--line)}.punch{position:absolute;left:12px;width:12px;height:12px;border-radius:50%;background:var(--bg);box-shadow:inset 0 1px 2px rgba(48,48,48,.18)}.punch.p1{top:12%}.punch.p2{top:47%}.punch.p3{top:82%}.card-meta{display:flex;gap:8px;align-items:center;margin-bottom:14px;flex-wrap:wrap}.chip{font-size:.75rem;font-weight:700;border-radius:99px;padding:3px 11px;background:var(--bg);color:var(--muted);border:1px solid var(--line)}.chip.subject{background:rgba(91,160,88,.12);border-color:transparent}.chip.diff-easy,.chip.subject{color:var(--primary-dark)}.chip.diff-medium{color:#b8860b}.chip.diff-hard{color:var(--wrong)}.chip.score{margin-left:auto;background:var(--accent);color:var(--text);border-color:transparent}.chip.timer{font-feature-settings:"tnum";font-variant-numeric:tabular-nums;color:var(--muted);background:transparent;border-style:dashed}.q-text{font-family:Nunito Sans,sans-serif;font-weight:800;font-size:1.25rem;line-height:1.45;margin:4px 0 20px}.choices{display:grid;grid-gap:10px;gap:10px}.choice{text-align:left;background:var(--bg);border:1.5px solid var(--line);border-radius:10px;padding:12px 16px;font-family:inherit;font-size:.98rem;color:var(--text);cursor:pointer;transition:border-color .12s,background .12s}.choice:hover:not(:disabled){border-color:var(--accent);background:#fffbef}.choice:disabled{cursor:default}.choice.correct{border-color:var(--primary);background:rgba(91,160,88,.14);font-weight:700}.choice.wrong{border-color:var(--wrong);background:rgba(217,99,78,.1)}.choice.dim{opacity:.55}.verdict{font-family:Nunito Sans,sans-serif;font-weight:900;font-size:1.05rem;margin:16px 0 4px}.verdict.right{color:var(--primary-dark)}.verdict.wrong{color:var(--wrong)}.flip-hint{color:var(--muted);font-size:.88rem;margin:2px 0 0}.back-title{font-family:Nunito Sans,sans-serif;font-weight:900;font-size:1.1rem;color:var(--primary-dark);margin:0 0 10px}.explanation{white-space:pre-wrap;font-size:.98rem}.study-actions{display:flex;gap:12px;margin-top:22px;flex-wrap:wrap}.gen-note{display:flex;align-items:center;gap:10px;color:var(--muted);margin-top:18px;font-size:.92rem}.spinner{width:18px;height:18px;border:3px solid var(--line);border-top-color:var(--accent);border-radius:50%;animation:spin .8s linear infinite}@keyframes spin{to{transform:rotate(1turn)}}.session-list{display:grid;grid-gap:14px;gap:14px}.session-row{display:flex;align-items:center;gap:14px;background:var(--surface);border-radius:var(--radius);box-shadow:var(--card-shadow);padding:18px 22px;text-decoration:none;color:var(--text);transition:transform .12s,box-shadow .12s}.session-row:hover{transform:translateY(-2px);box-shadow:0 12px 20px -6px rgba(48,48,48,.16)}.session-subject{font-family:Nunito Sans,sans-serif;font-weight:800;font-size:1.05rem}.session-date{color:var(--muted);font-size:.85rem}.session-score{margin-left:auto;font-weight:800;color:var(--primary-dark);white-space:nowrap}.review-list{display:grid;grid-gap:18px;gap:18px}.summary-num{font-family:Nunito Sans,sans-serif;font-size:3rem;font-weight:900;color:var(--primary);margin:8px 0}.empty-note{color:var(--muted);text-align:center;padding:40px 0}@media (max-width:560px){.card-face{padding-left:48px}.site-header .inner{gap:12px}.user-chip{display:none}.study-actions{flex-direction:column;align-items:stretch}.study-actions .btn{width:100%;text-align:center}.study-actions .btn:not(.secondary){order:-1}}@media (prefers-reduced-motion:reduce){.flipcard{transition:none}.spinner{animation-duration:2s}}