:root{--sts-green:#168347;--sts-red:#c62828;--sts-blue:#1269a8;--sts-orange:#d99000;--sts-bg:#eef3f7;--sts-border:#dbe4eb;--sts-text:#1f2b35}
.sts-exam{max-width:980px;margin:30px auto;padding:0 14px;color:var(--sts-text);font-family:Arial,Helvetica,sans-serif}
.sts-exam *{box-sizing:border-box}
.sts-exam__header,.sts-exam__status,.sts-question,.sts-result{background:#fff;border-radius:16px;box-shadow:0 8px 22px rgba(22,50,76,.09)}
.sts-exam__header{display:flex;justify-content:space-between;align-items:center;gap:20px;padding:24px;margin-bottom:15px;border-left:6px solid var(--sts-orange)}
.sts-exam__header h2{margin:0 0 6px;font-size:clamp(24px,4vw,36px)}.sts-exam__header p{margin:0}
.sts-exam__status{position:sticky;top:10px;z-index:10;display:flex;align-items:center;gap:18px;flex-wrap:wrap;padding:14px 18px;margin-bottom:18px}
.sts-progress{height:11px;background:#e1e9ef;border-radius:20px;overflow:hidden;flex:1;min-width:180px}.sts-progress span{display:block;height:100%;width:0;background:var(--sts-green);transition:width .25s}
.sts-question{padding:22px;margin-bottom:18px;border:1px solid #e5ebf0}.sts-question__number{font-weight:800;color:var(--sts-blue)}
.sts-question h3{font-size:20px;margin:5px 0 16px}.sts-answer{display:flex;align-items:center;gap:10px;padding:12px 14px;margin:9px 0;border:2px solid var(--sts-border);border-radius:11px;cursor:pointer;transition:.15s;background:#fff}
.sts-answer:hover{border-color:#8eb8d5;background:#f7fbfe}.sts-answer input{margin:0}.sts-answer__letter{display:inline-flex;align-items:center;justify-content:center;width:28px;height:28px;border-radius:50%;background:#edf3f7;font-weight:800}
.sts-answer.is-correct{background:#e7f7ed;border-color:var(--sts-green);color:#0d6a36}.sts-answer.is-wrong{background:#fdeaea;border-color:var(--sts-red);color:#8f1919}
.sts-feedback{display:none;margin-top:12px;padding:12px 14px;border-radius:10px}.sts-feedback.is-visible{display:block}.sts-feedback.is-good{background:#e7f7ed;color:#0c7338;border-left:5px solid var(--sts-green)}.sts-feedback.is-bad{background:#fdeaea;color:#991919;border-left:5px solid var(--sts-red)}
.sts-feedback__explanation{display:block;margin-top:4px}.sts-btn{border:0;border-radius:10px;padding:11px 17px;font-weight:800;cursor:pointer}.sts-btn--primary{background:var(--sts-blue);color:#fff}.sts-btn--light{background:#e7edf2;color:#23384b}
.sts-result{text-align:center;padding:30px;margin-top:25px}.sts-result__score{font-size:42px;font-weight:900;color:var(--sts-blue)}.sts-result__percentage{font-size:24px;font-weight:800}
@media(max-width:680px){.sts-exam__header{align-items:flex-start;flex-direction:column}.sts-exam__status{position:static}.sts-question{padding:17px}}

.sts-feedback__title{display:inline-block;font-size:18px;letter-spacing:.02em}
.sts-feedback.is-good .sts-feedback__title::before{content:"✓ ";font-size:21px}
.sts-feedback.is-bad .sts-feedback__title::before{content:"✕ ";font-size:21px}