.rm-course{--rm-ink:#15233a;--rm-muted:#4b5c74;--rm-line:#cdd8e6;--rm-accent:#1f6fb8;--rm-traveller:#c25f0b;max-width:1180px;color:var(--rm-ink);margin:2rem auto 5rem;padding:0 1rem}.rm-course__hero{color:#eaf2fb;background:#0b1626;border:1px solid #1d3352;border-radius:24px;padding:clamp(1.5rem,5vw,4rem);position:relative;overflow:hidden}.rm-course__hero--hub{grid-template-columns:minmax(0,1.4fr) minmax(250px,.8fr);align-items:center;gap:1.5rem;display:grid}.rm-course__hero-copy{z-index:1;min-width:0;position:relative}.rm-course__hub-link{color:#9fd0ff;font-size:.9rem;text-decoration:none}.rm-course__eyebrow{letter-spacing:.1em;color:#a6b8cf;margin:1.7rem 0 .8rem;font-size:.74rem}.rm-course__title{letter-spacing:-.035em;text-wrap:balance;max-width:1000px;margin:0;font-size:clamp(2rem,4.4vw,3.6rem);line-height:1.18}.rm-course__lead{color:#d3e0ef;max-width:920px;margin:1.5rem 0;font-size:clamp(1.05rem,1.6vw,1.2rem);line-height:1.85}.rm-course__byline{color:#9fb3cb;margin:1.4rem 0 0;font-size:.8rem}.rm-course__hero-art{min-width:0}.rm-course__spacetime-art{filter:drop-shadow(0 0 7px #8fd0ff33);width:100%;height:auto}.rm-course__reading-layout{grid-template-columns:210px minmax(0,1fr);gap:clamp(1.5rem,4vw,3.5rem);margin-top:2.5rem;display:grid}.rm-course__rail{align-self:start;min-width:0;font-size:.88rem;position:sticky;top:1.5rem}.rm-course__rail-heading{margin:0 0 .8rem;font-weight:700}.rm-course__section-nav{border-left:1px solid var(--rm-line);gap:.2rem;padding-left:1rem;display:grid}.rm-course__section-link{color:var(--rm-muted);padding:.3rem 0;line-height:1.55;text-decoration:none}.rm-course__section-link:hover{color:var(--rm-accent)}.rm-course__rail-return{color:var(--rm-accent);margin-top:1.5rem;display:inline-block}.rm-course__body{min-width:0;max-width:760px;font-size:1.04rem;line-height:1.95}.rm-course__heading{letter-spacing:-.02em;text-wrap:balance;margin:0 0 1rem;font-size:clamp(1.35rem,2.5vw,1.7rem);line-height:1.45}.rm-course__heading--on-dark{color:#fff}.rm-course__paragraph{margin:0 0 1.1rem}.rm-course__label{letter-spacing:.065em;color:var(--rm-accent);margin:0 0 .6rem;font-size:.76rem;font-weight:700;line-height:1.4}.rm-course__label--on-dark{color:#ffc98f}.rm-course__prerequisites{color:var(--rm-muted);border-left:3px solid #7fb4e6;margin-bottom:2.5rem;padding:.15rem 0 .15rem 1.2rem;font-size:.94rem}.rm-course__prerequisites-text{margin:0}.rm-course__section{margin:0 0 3.1rem;scroll-margin-top:2rem}.rm-course__section--worked{border:1px solid var(--rm-line);background:#eef3fa;border-radius:18px;padding:1.5rem}.rm-course__equation{max-width:100%;margin:.6rem 0 .4rem;padding:.6rem 0 .9rem;overflow-x:auto}.rm-course__task{color:#e3ecf8;background:#10203a;border-radius:20px;margin:3rem 0;padding:1.7rem;scroll-margin-top:2rem}.rm-course__task-list{margin:0 0 1.4rem;padding-left:1.5rem}.rm-course__task-step{padding:.25rem 0 .25rem .25rem}.rm-course__lab-links{flex-wrap:wrap;gap:.7rem;display:flex}.rm-course__lab-link{color:inherit;background:#ffffff09;border:1px solid #9ab8dc;border-radius:10px;justify-content:space-between;align-items:center;gap:1rem;max-width:100%;padding:.65rem .9rem;font-size:.94rem;line-height:1.5;text-decoration:none;display:inline-flex}.rm-course__lab-link--light{color:var(--rm-ink);background:#fffa}.rm-course__model-note{color:#bccbdf;margin:1.3rem 0 0;font-size:.82rem;line-height:1.65}.rm-course__exercises{scroll-margin-top:2rem}.rm-course__exercise{border-top:1px solid var(--rm-line);padding:.9rem 0 1.1rem}.rm-course__exercise-question{margin:0 0 .6rem;font-size:1.03rem;line-height:1.65}.rm-course__exercise-number{color:var(--rm-traveller)}.rm-course__answer-toggle{color:var(--rm-accent);cursor:pointer;font-size:.9rem}.rm-course__answer-text{color:var(--rm-muted);margin:.7rem 0 0}.rm-course__references{border-top:1px solid var(--rm-line);margin-top:2.5rem;padding-top:2rem;scroll-margin-top:2rem;font-size:.9rem}.rm-course__reference-list{padding-left:1.3rem}.rm-course__reference{margin-bottom:1.2rem}.rm-course__reference-link{color:var(--rm-accent);overflow-wrap:anywhere}.rm-course__reference-note{color:var(--rm-muted);margin:.4rem 0 0;font-size:.85rem;line-height:1.65}.rm-course__reading-nav{grid-template-columns:repeat(2,minmax(0,1fr));gap:1rem;margin-top:3rem;display:grid}.rm-course__reading-nav-link{border:1px solid var(--rm-line);color:var(--rm-ink);border-radius:13px;gap:.3rem;padding:1.1rem;font-size:.95rem;line-height:1.6;text-decoration:none;display:grid}.rm-course__reading-nav-link:hover{border-color:var(--rm-accent)}.rm-course__hub-body{padding:2.5rem clamp(0rem,2vw,1.5rem)}.rm-course__paths{grid-template-columns:repeat(2,minmax(0,1fr));gap:2.5rem;margin-bottom:3.5rem;display:grid}.rm-course__path-title{margin:.8rem 0;font-size:1.5rem}.rm-course__path-text{color:var(--rm-muted);line-height:1.85}.rm-course__path-link{color:var(--rm-accent);font-weight:600}.rm-course__chapter-index-title{margin:0 0 1.5rem;font-size:1.55rem;line-height:1.5}.rm-course__chapter-grid{grid-template-columns:repeat(2,minmax(0,1fr));gap:1rem;padding:0;list-style:none;display:grid}.rm-course__chapter-item{min-width:0}.rm-course__chapter-card{box-sizing:border-box;border:1px solid var(--rm-line);min-width:0;height:100%;color:var(--rm-ink);background:#fff5;border-radius:16px;flex-direction:column;padding:1.4rem;text-decoration:none;transition:border-color .15s,background .15s;display:flex}.rm-course__chapter-card:hover{border-color:var(--rm-accent);background:#edf3fb}.rm-course__chapter-number{color:#8a9bb3;justify-content:space-between;align-items:center;margin:0 0 1rem;font-size:1.4rem;font-weight:600;display:flex}.rm-course__level{color:var(--rm-accent);letter-spacing:.04em;border:1px solid #a3bfdf;border-radius:5px;padding:.15rem .45rem;font-size:.7rem}.rm-course__chapter-title{margin:0 0 .7rem;font-size:1.2rem;line-height:1.45}.rm-course__chapter-question{color:var(--rm-muted);margin:0 0 1.4rem;font-size:.94rem;line-height:1.75}.rm-course__card-action{color:var(--rm-accent);margin-top:auto;font-size:.85rem;font-weight:600}.rm-course__hub-labs{border:1px solid var(--rm-line);background:#ebf1f9;border-radius:18px;margin-top:3rem;padding:1.7rem}.rm-course__hub-labs-title{margin:0 0 .8rem;font-size:1.4rem}.rm-course__hub-labs-text{color:var(--rm-muted);margin:0 0 1.3rem;line-height:1.85}.rm-course__next-course{border-top:1px solid var(--rm-line);margin-top:2rem;padding-top:1.5rem}.rm-course__next-course-link{color:var(--rm-accent);font-size:1.05rem;font-weight:600}@media (width<=800px){.rm-course__hero--hub{grid-template-columns:1fr}.rm-course__hero-art{max-width:390px;margin:auto}.rm-course__reading-layout{grid-template-columns:1fr}.rm-course__rail{border-bottom:1px solid var(--rm-line);padding-bottom:1.3rem;position:static}.rm-course__section-nav{grid-template-columns:repeat(2,minmax(0,1fr));gap:.25rem 1.3rem}.rm-course__rail-return{margin-top:.8rem}.rm-course__body{max-width:none}.rm-course__paths{gap:1.5rem}.rm-course__title{font-size:2.25rem}}@media (width<=520px){.rm-course{margin-top:1rem;padding:0 .75rem}.rm-course__hero{border-radius:18px;padding:1.5rem}.rm-course__title{font-size:1.9rem}.rm-course__lead{font-size:1rem}.rm-course__paths,.rm-course__chapter-grid,.rm-course__reading-nav,.rm-course__section-nav{grid-template-columns:1fr}.rm-course__body{font-size:1rem;line-height:1.9}.rm-course__section--worked,.rm-course__task{padding:1.2rem}.rm-course__lab-link{width:100%}.rm-course__hero-art{max-width:320px}.rm-course__chapter-card,.rm-course__hub-labs{padding:1.2rem}}