/* Статья «Пятёрка по математике — а на олимпиаде ноль» (раздел «Статьи»). Все классы с префиксом fa- */
.fa{font-family:inherit;line-height:1.72;color:#fff;font-size:1.0625rem}
.fa-hero{border-radius:22px}
.fa{
  --fa-bg:#070C18; --field:#0B1428; --paper:#f6efe2; --ink:#14213d;
  --border:rgba(255,255,255,.09); --border-mid:rgba(255,255,255,.16);
  --text:#fff; --soft:rgba(255,255,255,.84); --muted:#94a3b8; --text-soft:#cbd5e1;
  --amber:#f4a259; --amber-l:#ffc98f; --teal:#5eead4; --green:#38ef7d; --green-d:#11998e; --red:#f87171;
  
  --serif:'Playfair Display','Georgia',serif;
  --fa-hdr:66px;
}
.fa,.fa *{box-sizing:border-box}
.fa img,.fa svg{max-width:100%;height:auto;display:block}
.fa a{color:var(--amber-l);text-underline-offset:3px}
.fa a:hover{color:#fff}
.fa :focus-visible{outline:3px solid var(--amber);outline-offset:3px;border-radius:6px}
.fa .fa-progress{position:fixed;inset:0 0 auto 0;height:3px;background:rgba(255,255,255,.06);z-index:9999}
.fa .fa-progress__bar{height:100%;width:0;background:linear-gradient(90deg,var(--amber),var(--amber-l));transition:width .1s linear}
.fa .fa-hero{position:relative;overflow:hidden;background:#0f1b38;min-height:clamp(480px,70vh,660px);display:flex;align-items:flex-end}
.fa .fa-hero__img{position:absolute;inset:0 0 0 auto;width:72%;height:100%;object-fit:cover;object-position:20% 40%}
.fa .fa-hero__shade{position:absolute;inset:0;background:linear-gradient(90deg,#0f1b38 0%,#0f1b38 28%,rgba(15,27,56,0) 55%),linear-gradient(0deg,#070C18 0%,rgba(7,12,24,0) 32%)}
.fa .fa-hero__inner{position:relative;width:100%;max-width:1180px;margin:0 auto;padding:clamp(56px,9vw,100px) clamp(20px,4vw,40px) clamp(48px,6vw,72px)}
.fa .fa-kicker{margin:0 0 20px;font-size:.875rem;color:var(--text-soft);font-weight:500}
.fa .fa-kicker span{color:var(--amber);font-weight:800;text-transform:uppercase;letter-spacing:.12em;margin-right:4px}
.fa .fa-hero h1{margin:0 0 20px;max-width:13ch;font-family:var(--serif);font-weight:800;font-size:clamp(2.1rem,5.6vw,4rem) !important;line-height:1.08;letter-spacing:-.01em;text-wrap:balance;color:#fff;font-variant-numeric:lining-nums}
.fa .fa-hero__lead{margin:0;max-width:34ch;font-size:clamp(1.05rem,2.2vw,1.25rem);line-height:1.55;color:#e6e9f2}
@media(max-width:719px){.fa .fa-hero{flex-direction:column;align-items:stretch;min-height:0}
.fa .fa-hero__img{position:relative;inset:auto;width:100%;height:250px;object-position:34% 40%}
.fa .fa-hero__shade{inset:0 0 auto 0;height:250px;background:linear-gradient(0deg,#0f1b38 0%,rgba(15,27,56,0) 55%)}
.fa .fa-hero__inner{padding:6px 20px 30px}
.fa .fa-hero h1{max-width:none}
.fa .fa-hero__lead{max-width:none}
}.fa .fa-hud{position:sticky;top:var(--fa-hdr);z-index:35;background:rgba(7,12,24,.92);backdrop-filter:blur(10px);border-bottom:1px solid var(--border)}
.fa .fa-hud ol{list-style:none;display:flex;justify-content:center;gap:0;margin:0 auto;padding:8px 12px;max-width:760px}
.fa .fa-hud li{flex:1;position:relative}
.fa .fa-hud li:not(:last-child)::after{content:"";position:absolute;top:19px;left:calc(50% + 18px);right:calc(-50% + 18px);border-top:2px dashed rgba(255,255,255,.22)}
.fa .fa-hud li.fa-is-done:not(:last-child)::after{border-top-style:solid;border-top-color:var(--amber)}
.fa .fa-hud a{display:flex;flex-direction:column;align-items:center;gap:2px;text-decoration:none;color:var(--muted);font-size:.75rem;font-weight:700;padding:2px 0}
.fa .fa-hud i{font-style:normal;display:grid;place-items:center;width:28px;height:28px;border-radius:50%;border:2px solid rgba(255,255,255,.28);background:#070C18;font-size:.8rem;font-weight:800;color:var(--muted);position:relative;z-index:1;transition:all .25s}
.fa .fa-hud .fa-is-done i{border-color:var(--amber);color:var(--amber)}
.fa .fa-hud .fa-is-active i{background:var(--amber);border-color:var(--amber);color:var(--ink);box-shadow:0 0 0 5px rgba(244,162,89,.2)}
.fa .fa-hud .fa-is-active{color:#fff}
@media(max-width:420px){.fa .fa-hud a span{font-size:.6875rem}
}.fa .fa-page{padding:clamp(16px,3vw,32px) clamp(16px,4vw,32px) 40px}
.fa article{max-width:1000px;margin:0 auto}
.fa .fa-chapter{max-width:680px;margin:0 auto;padding:clamp(40px,7vw,72px) 0;border-top:1px solid var(--border);scroll-margin-top:130px}
.fa .fa-chapter:first-child{border-top:0}
.fa .fa-chapter--wide{max-width:none}
.fa .fa-chapter--wide .fa-col{max-width:680px;margin-left:auto;margin-right:auto}
.fa .fa-chapter__no{margin:0 0 10px;font-size:.8125rem;font-weight:800;letter-spacing:.14em;text-transform:uppercase;color:var(--amber)}
.fa .fa-chapter__no--boss{color:var(--red)}
.fa .fa-chapter h2{margin:0 0 22px;font-family:var(--serif);font-weight:800;font-size:clamp(1.7rem,4.2vw,2.5rem) !important;line-height:1.15;letter-spacing:-.01em;text-wrap:balance;font-variant-numeric:lining-nums}
.fa .fa-chapter h3{margin:34px 0 10px;font-size:1.25rem;font-weight:800;line-height:1.3}
.fa .fa-chapter p{margin:0 0 18px;color:var(--soft)}
.fa .fa-chapter ul,.fa .fa-chapter ol{padding-left:1.3em;margin:0 0 20px;color:var(--soft)}
.fa .fa-chapter li{margin-bottom:8px}
.fa .fa-chapter strong{color:#fff}
.fa .fa-small{font-size:.9375rem;color:var(--muted)!important}
.fa .fa-pull{margin:30px 0 8px!important;padding-left:22px;border-left:4px solid var(--amber);font-family:var(--serif);font-style:italic;font-weight:600;font-size:clamp(1.4rem,3.4vw,2rem);line-height:1.3;color:#fff!important}
.fa .fa-task{position:relative;margin:26px 0;padding:26px 24px 8px;background:var(--paper);color:var(--ink);border-radius:6px 16px 16px 16px;box-shadow:0 14px 34px rgba(0,0,0,.45)}
.fa .fa-task::before{content:"";position:absolute;inset:6px;border:1px dashed rgba(20,33,61,.25);border-radius:3px 12px 12px 12px;pointer-events:none}
.fa .fa-task__tag{position:absolute;top:-11px;left:18px;padding:3px 12px;background:var(--ink);color:var(--amber);font-size:.75rem;font-weight:800;letter-spacing:.12em;text-transform:uppercase;border-radius:6px}
.fa .fa-chapter .fa-task p{color:var(--ink);font-size:1.08rem;line-height:1.6;margin-bottom:18px}
.fa .fa-chapter .fa-task strong{color:var(--ink)}
.fa .fa-fig{margin:26px 0}
.fa .fa-fig svg{background:var(--field);border:1px solid var(--border-mid);border-radius:16px;padding:14px;width:100%}
.fa .fa-fig--narrow svg{max-width:480px;margin:0 auto}
.fa .fa-fig figcaption{margin-top:10px;font-size:.9375rem;color:var(--muted);line-height:1.5}
.fa .fa-fig--narrow figcaption{max-width:480px;margin-left:auto;margin-right:auto}
.fa .fa-fig--pic img{width:100%;max-width:560px;aspect-ratio:1/1;object-fit:cover;border-radius:16px;border:1px solid var(--border-mid);box-shadow:0 16px 40px rgba(0,0,0,.5);background:#070C18}
@media(min-width:900px){.fa .fa-fig--pic{margin-left:-40px}
}.fa .fa-table-scroll{overflow-x:auto;margin:28px auto;max-width:860px;border:1px solid var(--border-mid);border-radius:16px;background:var(--field)}
.fa table{border-collapse:collapse;width:100%;min-width:520px;font-size:.9375rem;line-height:1.5}
.fa th,.fa td{padding:13px 18px;text-align:left;vertical-align:top;border-bottom:1px solid var(--border)}
.fa thead th{background:rgba(255,255,255,.05);color:var(--muted);font-weight:800;text-transform:uppercase;font-size:.75rem;letter-spacing:.1em}
.fa thead th:last-child{color:var(--amber)}
.fa tbody th{font-weight:700;color:#e2e8f0;width:26%}
.fa tbody td{color:var(--soft)}
.fa tbody td:last-child{color:#fff;background:rgba(244,162,89,.07)}
.fa tbody tr:last-child>*{border-bottom:0}
.fa .fa-asks{list-style:none;padding:0!important;margin:32px auto 0!important;max-width:900px;display:grid;gap:0;counter-reset:a}
.fa .fa-asks li{display:grid;grid-template-columns:auto 1fr;gap:20px;margin:0;padding:24px 0;border-top:1px solid var(--border-mid)}
.fa .fa-asks li:last-child{border-bottom:1px solid var(--border-mid)}
.fa .fa-asks__n{font-family:var(--serif);font-weight:800;font-size:clamp(2.6rem,6vw,3.6rem);line-height:.9;color:transparent;-webkit-text-stroke:1.5px var(--amber);min-width:1ch;font-variant-numeric:lining-nums}
.fa .fa-asks h3{margin:0 0 6px!important;font-size:1.2rem}
.fa .fa-asks p{margin:0!important;font-size:1rem}
@media(min-width:800px){.fa .fa-asks{grid-template-columns:1fr 1fr;column-gap:48px}
.fa .fa-asks li:nth-child(2){border-bottom:0}
.fa .fa-asks li:nth-child(3){border-bottom:1px solid var(--border-mid)}
.fa .fa-asks li:last-child{border-bottom:1px solid var(--border-mid)}
}.fa .fa-spoiler,.fa .fa-faq{background:var(--field);border:1px solid var(--border-mid);border-radius:14px;margin:20px 0;overflow:hidden}
.fa .fa-spoiler summary,.fa .fa-faq summary{cursor:pointer;list-style:none;padding:14px 18px;font-weight:800;color:#fff;display:flex;align-items:center;gap:12px;min-height:50px}
.fa .fa-spoiler summary::-webkit-details-marker,.fa .fa-faq summary::-webkit-details-marker{display:none}
.fa .fa-spoiler summary::before{content:"?";flex:none;display:grid;place-items:center;width:26px;height:26px;border-radius:8px;background:var(--amber);color:var(--ink);font-size:.9rem}
.fa .fa-spoiler summary::after,.fa .fa-faq summary::after{content:"+";margin-left:auto;flex:none;width:28px;height:28px;border-radius:50%;background:rgba(244,162,89,.12);border:1px solid rgba(244,162,89,.45);color:var(--amber);display:grid;place-items:center;font-size:1.15rem;line-height:1;transition:transform .2s}
.fa .fa-spoiler[open] summary::after,.fa .fa-faq[open] summary::after{transform:rotate(45deg)}
.fa .fa-spoiler[open] summary,.fa .fa-faq[open] summary{border-bottom:1px solid var(--border);background:rgba(244,162,89,.06)}
.fa .fa-spoiler>div,.fa .fa-faq>div{padding:16px 18px 2px}
.fa .fa-spoiler:hover,.fa .fa-faq:hover{border-color:rgba(244,162,89,.45)}
.fa .fa-fact{background:rgba(94,234,212,.07);border:1px solid rgba(94,234,212,.3);border-left:4px solid var(--teal);border-radius:12px;padding:14px 18px;margin:24px 0 0;font-size:.9375rem;line-height:1.6;color:var(--soft)}
.fa .fa-fact strong{color:var(--teal)!important}
.fa .fa-think{list-style:none;padding:0!important;counter-reset:t}
.fa .fa-think li{counter-increment:t;position:relative;margin:0 0 10px;padding:12px 16px 12px 54px;background:var(--field);border:1px solid var(--border-mid);border-radius:12px;font-style:italic;color:#e2e8f0}
.fa .fa-think li::before{content:counter(t);position:absolute;left:14px;top:12px;width:28px;height:28px;border-radius:50%;background:var(--amber);color:var(--ink);font-style:normal;font-weight:800;font-size:.85rem;display:grid;place-items:center}
.fa .fa-gear{list-style:none;padding:0!important;display:grid;gap:12px}
.fa .fa-gear li{display:flex;gap:16px;align-items:flex-start;margin:0;background:var(--field);border:1px solid var(--border-mid);border-radius:14px;padding:14px 18px}
.fa .fa-gear__tag{flex:none;width:78px;text-align:center;padding:4px 10px;border-radius:8px;background:rgba(244,162,89,.12);border:1px solid rgba(244,162,89,.4);color:var(--amber);font-size:.75rem;font-weight:800;letter-spacing:.04em;margin-top:2px}
.fa .fa-gear__tag--brand{background:rgba(56,239,125,.12);border-color:rgba(56,239,125,.4);color:#86efac}
.fa .fa-gear div{display:flex;flex-direction:column;line-height:1.5}
.fa .fa-gear div span{color:var(--muted);font-size:.9375rem}
.fa .fa-stages{list-style:none;padding:0!important;margin:30px auto!important;max-width:900px;display:grid;gap:0;position:relative}
.fa .fa-stages li{position:relative;margin:0;padding:0 0 26px 58px}
.fa .fa-stages li:last-child{padding-bottom:0}
.fa .fa-stages li:not(:last-child)::before{content:"";position:absolute;left:19px;top:42px;bottom:0;border-left:2px dashed rgba(255,255,255,.28)}
.fa .fa-stages b{position:absolute;left:0;top:0;width:40px;height:40px;border-radius:50%;background:var(--amber);color:var(--ink);display:grid;place-items:center;font-weight:800}
.fa .fa-stages h3{margin:0!important;font-size:1.15rem}
.fa .fa-stages p{margin:0!important}
.fa .fa-stages__d{color:var(--amber-l)!important;font-weight:800}
.fa .fa-stages__c{color:var(--muted)!important;font-size:.875rem}
@media(min-width:800px){.fa .fa-stages{grid-template-columns:repeat(4,1fr);gap:16px}
.fa .fa-stages li{padding:56px 0 0}
.fa .fa-stages li:not(:last-child)::before{left:52px;right:-16px;top:19px;bottom:auto;border-left:0;border-top:2px dashed rgba(255,255,255,.28)}
}.fa .fa-traps{list-style:none;padding:0!important}
.fa .fa-traps li{margin:0;padding:14px 0 14px 40px;position:relative;border-top:1px solid var(--border)}
.fa .fa-traps li:last-child{border-bottom:1px solid var(--border)}
.fa .fa-traps li::before{content:"×";position:absolute;left:4px;top:11px;font-size:1.6rem;line-height:1;font-weight:800;color:var(--red)}
.fa .fa-tracker{background:var(--field);border:1px solid var(--border-mid);border-radius:16px;padding:20px;margin:26px 0}
.fa .fa-tracker__head{display:flex;justify-content:space-between;align-items:baseline;margin-bottom:14px}
.fa .fa-tracker__head span{color:var(--amber);font-weight:800}
.fa .fa-tracker__days{display:grid;grid-template-columns:repeat(6,1fr);gap:8px}
@media(min-width:560px){.fa .fa-tracker__days{grid-template-columns:repeat(10,1fr)}
}.fa .fa-day{appearance:none;border:1px solid var(--border-mid);background:rgba(255,255,255,.03);color:var(--text-soft);border-radius:10px;min-height:44px;font:inherit;font-weight:700;cursor:pointer;transition:background .15s,transform .1s,border-color .15s}
.fa .fa-day:hover{border-color:var(--amber)}
.fa .fa-day:active{transform:scale(.96)}
.fa .fa-day[aria-pressed="true"]{background:var(--amber);border-color:var(--amber);color:var(--ink)}
.fa .fa-tracker__bar{height:8px;border-radius:99px;background:rgba(255,255,255,.08);margin:16px 0 10px;overflow:hidden}
.fa .fa-tracker__bar div{height:100%;width:0;background:var(--amber);transition:width .25s}
.fa .fa-tracker .fa-small{margin:0!important}
.fa .fa-signpost{margin:28px 0 0;padding:18px 20px;border:1px dashed var(--border-mid);border-radius:14px;background:rgba(255,255,255,.02)}
.fa .fa-signpost p{margin:0 0 8px!important;font-size:.9375rem}
.fa .fa-signpost a{font-weight:800}
.fa .fa-finale{max-width:760px;margin:24px auto 0;padding:clamp(28px,5vw,48px);border-radius:22px;background:linear-gradient(135deg,#1c2a4d,#0f1b38);border:1px solid rgba(244,162,89,.4);box-shadow:0 20px 60px rgba(0,0,0,.45)}
.fa .fa-finale__k{margin:0 0 8px;font-size:.8125rem;font-weight:800;letter-spacing:.14em;text-transform:uppercase;color:var(--amber)}
.fa .fa-finale h2{margin:0 0 16px;font-family:var(--serif);font-weight:800;font-size:clamp(1.5rem,3.6vw,2.1rem) !important;line-height:1.2;text-wrap:balance}
.fa .fa-finale p{color:var(--soft)}
.fa .fa-cta-row{display:flex;flex-wrap:wrap;gap:12px;margin:22px 0 0}
.fa .fa-btn-amber{display:inline-block;padding:13px 26px;border-radius:12px;background:var(--amber);color:var(--ink);font-weight:800;text-decoration:none;min-height:48px;transition:transform .15s,box-shadow .15s}
.fa .fa-btn-amber:hover{color:var(--ink);background:var(--amber-l);transform:translateY(-2px);box-shadow:0 10px 26px rgba(244,162,89,.3)}
.fa .fa-btn-ghost{display:inline-block;padding:12px 24px;border-radius:12px;border:1px solid var(--border-mid);color:#fff;font-weight:700;text-decoration:none;min-height:48px;transition:background .2s,border-color .2s}
.fa .fa-btn-ghost:hover{color:#fff;background:rgba(255,255,255,.06);border-color:var(--amber)}
.fa .fa-finale__end{margin:26px 0 0!important;font-family:var(--serif);font-style:italic;font-size:1.4rem;color:var(--amber)!important}
@media(prefers-reduced-motion:reduce){.fa,.fa *{scroll-behavior:auto!important;transition:none!important}
}