@keyframes _si{to{opacity:1}}

.legacy-content .lesson-header {position:relative;overflow:hidden;padding:42px 38px;border:1px solid rgba(217,149,24,.24);border-radius:24px;background:radial-gradient(circle at 88% 12%,rgba(244,185,66,.25),transparent 34%),linear-gradient(145deg,#fffaf0,var(--card));box-shadow:0 18px 50px rgba(100,64,7,.09)}.legacy-content .lesson-header:after {content:"RUST";position:absolute;right:24px;bottom:-10px;font-size:86px;font-weight:900;color:rgba(217,149,24,.07);line-height:1}.legacy-content .subtitle {max-width:760px;position:relative;z-index:1}.legacy-content .goal, .legacy-content .snapshot, .legacy-content .takeaway {margin-top:18px;border:1px solid rgba(217,149,24,.22);background:var(--soft);border-radius:16px;padding:16px 20px;line-height:1.7}.legacy-content .goal b, .legacy-content .snapshot b, .legacy-content .takeaway b {color:var(--accent)}.legacy-content .section-title {margin:34px 0 14px;font-size:13px;font-weight:800;letter-spacing:.12em;color:var(--accent)}.legacy-content .facts {display:grid;grid-template-columns:repeat(4,1fr);gap:13px}.legacy-content .fact, .legacy-content .panel, .legacy-content .code-card {padding:19px;border:1px solid var(--border);border-radius:16px;background:var(--card);box-shadow:var(--shadow-card)}.legacy-content .fact svg {width:28px;height:28px;color:var(--accent)}.legacy-content .fact h3 {font-size:14px;margin:10px 0 5px}.legacy-content .fact p, .legacy-content .panel p, .legacy-content .snapshot {font-size:13px;color:var(--sub);line-height:1.65}.legacy-content .lane {display:grid;grid-template-columns:1fr 70px 1fr;align-items:stretch}.legacy-content .lane .mid {display:grid;place-items:center;color:var(--accent)}.legacy-content .lane .panel:first-child {border-color:rgba(217,149,24,.35)}.legacy-content .tag {display:inline-block;padding:4px 9px;border-radius:99px;background:var(--soft);color:var(--accent);font-size:11px;font-weight:800;letter-spacing:.08em}.legacy-content .panel h3 {margin:10px 0;font-size:17px}.legacy-content .panel ul {padding-left:18px;margin:0}.legacy-content .panel li {margin:8px 0;color:var(--text);font-size:13px;line-height:1.6}.legacy-content .source-grid {display:grid;grid-template-columns:1fr 1fr;gap:16px}.legacy-content .path {font:700 11px/1.5 ui-monospace,monospace;color:var(--accent);overflow-wrap:anywhere}.legacy-content .code {margin-top:9px;padding:15px;border-radius:12px;background:var(--surface-soft);color:var(--muted);overflow:auto;font:12px/1.65 ui-monospace,monospace}.legacy-content .cm {color:#aa9570}.legacy-content .kw {color:#ffc85a}.legacy-content .compare {padding:22px;border-radius:18px;background:var(--surface-soft);color:var(--muted)}.legacy-content .compare h3 {margin:0 0 12px;color:#ffc85a}.legacy-content .compare-grid {display:grid;grid-template-columns:1fr 1fr;gap:14px}.legacy-content .compare-grid div {padding:14px;border:1px solid rgba(255,213,125,.2);border-radius:12px;font-size:13px;line-height:1.65}.legacy-content .compare small {display:block;margin-top:12px;color:var(--muted)}.legacy-content .exercise {padding:20px;border:1px dashed rgba(217,149,24,.48);border-radius:18px;background:linear-gradient(120deg,var(--soft),transparent)}.legacy-content .exercise h3 {margin:0 0 6px}.legacy-content .exercise p {margin:0;color:var(--sub);line-height:1.7}.legacy-content .takeaway {display:flex;gap:12px}.legacy-content .takeaway svg {width:26px;flex:none;color:var(--accent)}@media(max-width:760px){.legacy-content .lesson-header {padding:30px 22px}.legacy-content .lesson-header:after {font-size:54px}.legacy-content .facts {grid-template-columns:1fr 1fr}.legacy-content .lane {grid-template-columns:1fr;gap:12px}.legacy-content .lane .mid {transform:rotate(90deg);height:35px}.legacy-content .source-grid, .legacy-content .compare-grid {grid-template-columns:1fr}}@media(max-width:430px){.legacy-content .facts {grid-template-columns:1fr}}