.radix-lesson {
    --rl-bg:#f8f9fc;
    --rl-paper:#fff;
    --rl-text:#192338;
    --rl-muted:#647084;
    --rl-line:#e3e7ef;
    --rl-accent:#1447e6;
    --rl-soft:#eef2ff;
    background:var(--rl-bg);
    color:var(--rl-text);
    font-family:Inter,ui-sans-serif,system-ui,sans-serif;
    padding-bottom:76px;
    line-height:1.75
}

.dark .radix-lesson {
    --rl-bg:#111827;
    --rl-paper:#1b2535;
    --rl-text:#edf0f8;
    --rl-muted:#a7b2c6;
    --rl-line:#344055;
    --rl-accent:#93c5fd;
    --rl-soft:#2c2546
}

.radix-lesson * {
    box-sizing:border-box
}

.radix-lesson [hidden] {
    display:none!important
}

.radix-lesson a {
    color:inherit;
    text-decoration:none
}

.radix-lesson button,.radix-lesson input {
    font-family:inherit
}

.radix-lesson button {
    cursor:pointer
}

.radix-lesson :focus-visible {
    outline:3px solid var(--rl-accent);
    outline-offset:4px
}

.radix-lesson sub {
    font-size:.55em
}

.radix-lesson sup {
    font-size:.7em
}

.rl-wrap {
    max-width:1200px;
    margin:auto;
    padding:0 28px
}

.rl-hero {
    position:relative;
    overflow:hidden;
    background:var(--rl-paper);
    border-bottom:1px solid var(--rl-line);
    isolation:isolate;
}

.rl-hero::before,.rl-hero::after {
    content:'';
    position:absolute;
    z-index:-1;
    width:65%;
    height:110%;
    top:-5%;
    filter:blur(64px);
    opacity:.1;
    pointer-events:none;
}

.rl-hero::before {
    left:-30%;
    background:linear-gradient(to right,#1447e6,#7008e7);
    transform:skewX(-12deg);
}

.rl-hero::after {
    right:-35%;
    background:linear-gradient(to left,#7008e7,#1447e6);
    transform:skewX(12deg);
}

.dark .rl-hero {
    background:#111827;
}

.dark .rl-hero::before,.dark .rl-hero::after {
    opacity:.26;
}

.rl-hero-layout {
    display:grid;
    grid-template-columns:1.3fr .85fr;
    gap:40px;
    align-items:center;
    padding:40px 0;
}

.rl-eyebrow {
    display:inline-flex;
    align-items:center;
    gap:8px;
    color:var(--rl-accent);
    font-size:10px;
    letter-spacing:.13em;
    font-weight:800;
    text-transform:uppercase
}

.rl-hero h1 {
    font-size:clamp(30px,3.8vw,48px);
    font-weight:900;
    letter-spacing:-.035em;
    line-height:1.35;
    margin:0 0 18px;
}

.rl-title-highlight {
    display:inline-block;
    color:#1447e6;
    background:linear-gradient(to right,#1447e6,#7008e7);
    background-clip:text;
    -webkit-background-clip:text;
    -webkit-text-fill-color:transparent;
}

.dark .rl-title-highlight {
    color:#93c5fd;
    background:linear-gradient(to right,#93c5fd,#c4b5fd);
    background-clip:text;
    -webkit-background-clip:text;
}

.rl-lead {
    font-size:15px;
    max-width:510px;
    color:var(--rl-muted);
    line-height:1.9
}

.rl-meta {
    display:flex;
    gap:18px;
    flex-wrap:wrap;
    font-size:10px;
    color:var(--rl-muted);
    margin:24px 0
}

.rl-meta i {
    margin-right:5px
}

.rl-actions {
    display:flex;
    align-items:center;
    flex-wrap:wrap;
    gap:10px;
    margin-top:28px
}

.radix-lesson .btn-tech-info {
    color:#fff;
}

.rl-actions a,.rl-bottom .btn-tech-info {
    min-height:44px;
    justify-content:center;
}

.rl-hero .rl-bit-row .is-on {
    background:linear-gradient(to right,#1447e6,#7008e7);
    border-color:#8493f6;
}

.rl-hero .rl-card-dot {
    background:#93c5fd;
}

.radix-lesson .rl-text-link {
    font-size:12px;
    font-weight:750;
    color:var(--rl-accent);
    background:none;
    border:0;
    padding:7px 0
}

.rl-text-link:hover {
    text-decoration:underline
}

.rl-bit-card {
    width:100%;
    max-width:380px;
    justify-self:end;
    background:#192337;
    color:#fff;
    border-radius:16px;
    padding:18px 20px;
    box-shadow:0 22px 48px -23px #15203b70;
    position:relative;
    overflow:hidden
}

.rl-bit-card:before {
    content:'';
    position:absolute;
    width:230px;
    height:230px;
    background:radial-gradient(circle,#7950d833,transparent 70%);
    right:-70px;
    top:-60px;
    pointer-events:none
}

.rl-card-top {
    display:flex;
    justify-content:space-between;
    align-items:center;
    gap:10px;
    flex-wrap:wrap;
    font-size:9px;
    letter-spacing:.12em;
    color:#a9b3c7;
    font-weight:750
}

.rl-mini-tag {
    display:inline-block;
    font-size:9px;
    letter-spacing:.08em;
    font-weight:750;
    border-radius:5px;
    padding:4px 8px;
    background:#ffffff0d;
    color:inherit
}

.rl-equation {
    font-size:32px;
    font-weight:750;
    display:flex;
    gap:14px;
    align-items:center;
    justify-content:center;
    letter-spacing:-.04em;
    padding:14px 0 12px;
    white-space:nowrap
}

.rl-equals {
    font-size:21px;
    color:#8c96aa
}

.rl-bit-row {
    display:flex;
    justify-content:center;
    gap:7px;
    margin-bottom:21px
}

.rl-bit-row>span {
    width:36px;
    height:36px;
    border:1px solid #465069;
    border-radius:8px;
    text-align:center;
    font-size:18px;
    padding:1px;
    position:relative;
    color:#7c899f
}

.rl-bit-row .is-on {
    background:#7750d7;
    border-color:#9474e7;
    color:#fff
}

.rl-bit-row small {
    position:absolute;
    top:38px;
    left:0;
    right:0;
    color:#93a1bb;
    font-size:10px
}

.rl-bit-card>p {
    display:flex;
    align-items:center;
    justify-content:center;
    gap:7px;
    font-size:12px;
    margin:16px 0 10px;
    color:#c0c9db
}

.rl-bit-card strong {
    color:#fff
}

.rl-card-dot {
    width:6px;
    height:6px;
    border-radius:50%;
    background:#b09af8
}

.rl-card-footer {
    border-top:1px solid #344055;
    padding-top:10px;
    text-align:center;
    font-size:10px;
    line-height:1.9;
    color:#aebbd0
}

.rl-layout {
    display:grid;
    grid-template-columns:230px minmax(0,1fr);
    gap:58px;
    padding-top:44px
}

.rl-layout--guest { display:block; max-width:1040px; margin:0 auto; }
.rl-layout--guest .rl-next { margin-top:32px; }
.rl-gate {
    display:grid;
    grid-template-columns:minmax(0,1.25fr) minmax(0,.85fr);
    gap:32px;
    padding:32px;
    border:1px solid var(--rl-line);
    border-radius:20px;
    background:var(--rl-paper);
    scroll-margin-top:100px;
}
.rl-gate h2 { font-size:clamp(25px,2.8vw,34px); font-weight:850; letter-spacing:-.035em; line-height:1.3; margin:14px 0 16px; }
.rl-gate-copy>p { color:var(--rl-muted); font-size:14px; line-height:1.9; }
.rl-gate-benefits { list-style:none; padding:0; margin:24px 0; }
.rl-gate-benefits>li { display:flex; align-items:flex-start; gap:12px; margin:18px 0; }
.rl-gate-benefits>li>span { display:grid; place-items:center; flex-shrink:0; width:26px; height:26px; border-radius:8px; background:var(--rl-soft); color:var(--rl-accent); font-weight:800; }
.rl-gate-benefits strong { font-size:14px; }
.rl-gate-benefits p,.rl-gate-roadmap p { margin:4px 0 0; font-size:13px; line-height:1.8; color:var(--rl-muted); }
.rl-gate-copy>.rl-gate-note { font-size:12px; margin:15px 0 0; }
.rl-gate-preview { background:var(--rl-soft); border:1px solid var(--rl-line); border-radius:16px; padding:24px; align-self:start; }
.rl-gate-lock { display:grid; place-items:center; width:48px; height:48px; background:var(--rl-paper); color:var(--rl-accent); border-radius:14px; margin-bottom:20px; }
.rl-gate-lock svg { width:26px; height:26px; stroke:currentColor; stroke-width:1.7; stroke-linecap:round; }
.rl-gate-preview h3 { font-size:19px; font-weight:800; margin:10px 0 22px; line-height:1.45; }
.rl-gate-roadmap { list-style:none; padding:0; margin:0; }
.rl-gate-roadmap li { display:flex; align-items:flex-start; gap:12px; margin:20px 0; }
.rl-gate-roadmap li>span { color:var(--rl-accent); font-size:12px; font-weight:800; padding-top:2px; }
.rl-gate-roadmap strong { font-size:14px; }
.rl-gate-access { border-top:1px solid var(--rl-line); padding-top:16px; margin-top:24px; font-size:12px; font-weight:650; color:var(--rl-accent); }
@media(max-width:800px) {
    .rl-gate { grid-template-columns:1fr; gap:24px; padding:24px; }
    .rl-gate-preview { padding:20px; }
}
@media(max-width:400px) {
    .rl-gate { padding:20px; }
    .rl-gate .rl-actions a { width:100%; }
}

.rl-sidebar-inner {
    position:sticky;
    top:105px
}

.rl-toc {
    display:grid;
    gap:7px;
    margin:20px 0 30px
}

.rl-toc a {
    padding:10px 12px;
    border-radius:8px;
    font-size:12px;
    font-weight:650;
    color:var(--rl-muted)
}

.rl-toc a span {
    font-size:10px;
    margin-right:11px;
    opacity:.7
}

.rl-toc a:hover,.rl-toc .is-current {
    background:var(--rl-soft);
    color:var(--rl-accent)
}

.rl-sidebar-note {
    border-top:1px solid var(--rl-line);
    padding:24px 12px;
    font-size:11px;
    color:var(--rl-muted)
}

.rl-sidebar-note>i {
    display:block;
    font-size:18px;
    margin-bottom:12px;
    color:var(--rl-accent)
}

.rl-sidebar-note strong {
    display:block;
    color:var(--rl-text);
    font-size:12px
}

.rl-sidebar-note p {
    margin:6px 0 10px
}

.rl-sidebar-note a {
    color:var(--rl-accent);
    font-weight:750
}

.rl-section {
    padding-bottom:45px;
    margin-bottom:43px;
    border-bottom:1px solid var(--rl-line);
    scroll-margin-top:110px
}

.rl-section-heading {
    display:flex;
    align-items:center;
    gap:15px;
    margin-bottom:22px
}

.rl-number {
    display:flex;
    align-items:center;
    justify-content:center;
    flex-shrink:0;
    width:38px;
    height:43px;
    border-radius:10px;
    background:var(--rl-soft);
    color:var(--rl-accent);
    font-size:13px;
    font-weight:800
}

.rl-section h2 {
    font-size:25px;
    letter-spacing:-.035em;
    line-height:1.3;
    font-weight:800;
    margin:4px 0
}

.rl-section>p {
    font-size:14px;
    color:var(--rl-muted);
    margin:15px 0;
    line-height:1.95
}

.rl-section p strong {
    color:var(--rl-text)
}

.rl-section h3 {
    font-size:17px;
    letter-spacing:-.025em;
    font-weight:750;
    margin:25px 0 10px
}

.rl-base-grid {
    display:grid;
    grid-template-columns:repeat(4,minmax(0,1fr));
    gap:10px;
    margin:24px 0 30px
}

.rl-base-grid>div {
    padding:17px 14px;
    border:1px solid var(--rl-line);
    border-radius:11px;
    background:var(--rl-paper)
}

.rl-base-grid .rl-highlight {
    border-color:#b5a2e8;
    background:var(--rl-soft)
}

.rl-base-grid span {
    display:block;
    color:var(--rl-accent);
    font-size:10px;
    font-weight:800;
    letter-spacing:.08em
}

.rl-base-grid strong {
    display:block;
    font-size:15px;
    margin:9px 0 5px
}

.rl-base-grid p {
    font-size:10px;
    color:var(--rl-muted);
    margin:0;
    line-height:1.9
}

.rl-lab {
    background:var(--rl-paper);
    border:1px solid var(--rl-line);
    border-radius:16px;
    padding:25px;
    margin:25px 0
}

.rl-lab-heading {
    display:flex;
    justify-content:space-between;
    align-items:center;
    gap:15px
}

.rl-lab h3 {
    margin:7px 0 0;
    font-size:17px
}

.rl-lab>p {
    font-size:14px;
    color:var(--rl-muted);
    margin:14px 0 21px
}

.rl-lab-tag {
    font-size:9px;
    color:var(--rl-muted);
    background:var(--rl-bg);
    padding:4px 8px;
    border-radius:5px;
    white-space:nowrap
}

.rl-switches {
    display:flex;
    gap:12px;
    justify-content:center
}

.rl-bit-switch {
    width:63px;
    min-height:78px;
    border:1px solid var(--rl-line);
    border-radius:11px;
    background:var(--rl-bg);
    color:var(--rl-muted)
}

.rl-bit-switch span {
    font-size:24px;
    display:block;
    font-weight:750;
    line-height:1.5
}

.rl-bit-switch small {
    font-size:10px;
    display:block
}

.rl-bit-switch[aria-pressed=true] {
    background:var(--rl-soft);
    border-color:#a48adf;
    color:var(--rl-accent)
}

.rl-bit-switch:hover {
    border-color:var(--rl-accent)
}

.rl-live-result {
    display:flex;
    align-items:center;
    justify-content:center;
    gap:16px;
    padding-top:22px;
    font-size:13px;
    color:var(--rl-muted)
}

.rl-live-result strong {
    font-size:24px;
    color:var(--rl-accent)
}

.rl-tip {
    display:flex;
    gap:14px;
    padding:8px 0;
    font-size:12px;
    color:var(--rl-muted)
}

.rl-tip>span {
    font-size:25px;
    color:var(--rl-accent)
}

.rl-tip p {
    margin:0
}

.rl-worked {
    border:1px solid var(--rl-line);
    border-radius:14px;
    background:var(--rl-paper);
    overflow:hidden;
    margin:24px 0
}

.rl-worked-header {
    display:flex;
    align-items:center;
    justify-content:space-between;
    padding:16px 22px;
    background:var(--rl-soft);
    gap:14px
}

.rl-worked-header strong {
    font-size:18px;
    color:var(--rl-accent)
}

.rl-worked-header>span {
    font-size:10px;
    color:var(--rl-muted)
}

.rl-table-scroll {
    overflow-x:auto
}

.rl-worked table {
    width:100%;
    border-collapse:collapse;
    font-size:12px;
    text-align:center;
    white-space:nowrap
}

.rl-worked th {
    font-size:10px;
    font-weight:650;
    color:var(--rl-muted);
    padding:13px 15px;
    border-bottom:1px solid var(--rl-line);
    text-align:center
}

.rl-worked td {
    padding:10px 15px;
    border-bottom:1px solid var(--rl-line);
    font-variant-numeric:tabular-nums
}

.rl-worked td:first-child {
    color:var(--rl-muted);
    font-size:10px
}

.rl-remainder {
    display:inline-flex;
    align-items:center;
    justify-content:center;
    width:27px;
    height:27px;
    border-radius:7px;
    background:var(--rl-soft);
    color:var(--rl-accent);
    font-weight:750
}

.rl-worked-answer {
    padding:17px 22px;
    display:flex;
    justify-content:space-between;
    align-items:center;
    gap:15px;
    font-size:11px;
    color:var(--rl-muted)
}

.rl-worked-answer>strong {
    font-size:25px;
    color:var(--rl-accent)
}

.rl-formula {
    padding:21px;
    background:var(--rl-paper);
    border:1px solid var(--rl-line);
    border-radius:11px;
    font-size:13px;
    line-height:2;
    font-variant-numeric:tabular-nums
}

.rl-mistake {
    border-left:3px solid #d7a33a;
    background:#f3c86b12;
    padding:15px 18px;
    margin-top:24px;
    font-size:12px
}

.rl-mistake>strong {
    font-size:12px
}

.rl-mistake p {
    color:var(--rl-muted);
    margin:5px 0 0
}

.rl-example-grid {
    display:grid;
    grid-template-columns:1fr 1fr;
    gap:17px;
    margin:25px 0
}

.rl-example-grid article {
    padding:21px;
    background:var(--rl-paper);
    border:1px solid var(--rl-line);
    border-radius:13px
}

.rl-example-grid .rl-mini-tag {
    background:var(--rl-soft);
    color:var(--rl-accent)
}

.rl-example-grid h3 {
    margin:16px 0 12px;
    font-size:25px
}

.rl-example-grid p {
    font-size:12px;
    line-height:2;
    color:var(--rl-muted)
}

.rl-example-grid article>div {
    border-top:1px solid var(--rl-line);
    padding-top:12px;
    font-size:10px;
    color:var(--rl-muted)
}

.rl-example-grid article>div strong {
    font-size:13px;
    color:var(--rl-text)
}

.rl-details {
    border:1px solid var(--rl-line);
    background:var(--rl-paper);
    border-radius:11px;
    margin-top:25px;
    font-size:12px
}

.rl-details summary {
    padding:17px 20px;
    font-weight:700;
    cursor:pointer
}

.rl-details>div {
    padding:0 20px 17px;
    color:var(--rl-muted)
}

.rl-details p {
    margin:10px 0
}

.rl-question-top {
    display:flex;
    justify-content:space-between;
    margin-bottom:10px
}

.rl-question-label {
    font-size:10px;
    font-weight:800;
    color:var(--rl-accent);
    letter-spacing:.05em;
    text-transform:uppercase
}

.rl-question-type {
    font-size:10px;
    color:var(--rl-muted)
}

.rl-answer-row {
    display:flex;
    gap:10px
}

.rl-answer-row input {
    min-width:0;
    flex:1;
    border:1px solid var(--rl-line);
    border-radius:8px;
    background:var(--rl-bg);
    color:var(--rl-text);
    padding:10px 13px;
    font-size:13px;
    box-shadow:none
}

.rl-answer-row input::placeholder {
    color:var(--rl-muted)
}

.rl-answer-row input[aria-invalid=true] {
    border-color:#c66161
}

.rl-feedback {
    font-size:11px;
    margin:8px 0 0;
    min-height:0
}

.rl-feedback:empty {
    display:none
}

.rl-feedback.is-correct {
    color:#20805c
}

.dark .rl-feedback.is-correct {
    color:#7bdbb2
}

.rl-feedback.is-incorrect {
    color:#b34848
}

.dark .rl-feedback.is-incorrect {
    color:#f59e9e
}

.rl-complete {
    display:flex;
    gap:15px;
    background:var(--rl-soft);
    border:1px solid var(--rl-line);
    padding:20px;
    border-radius:11px;
    margin-top:20px
}

.rl-complete>span {
    font-size:30px;
    color:var(--rl-accent)
}

.rl-complete h3 {
    margin:0 0 6px
}

.rl-complete p {
    font-size:12px;
    margin:0;
    color:var(--rl-muted)
}

.rl-next {
    display:grid;
    grid-template-columns:1fr 170px;
    gap:35px;
    align-items:center;
    background:var(--rl-soft);
    border:1px solid var(--rl-line);
    border-radius:17px;
    padding:30px;
    overflow:hidden
}

.rl-next h2 {
    font-size:25px;
    font-weight:800;
    letter-spacing:-.04em;
    margin:10px 0
}

.rl-next p {
    font-size:14px;
    color:var(--rl-muted);
    line-height:1.9
}

.rl-next ul {
    list-style:none;
    padding:0;
    margin:17px 0;
    font-size:13px
}

.rl-next li {
    margin:6px 0
}

.rl-next li:before {
    content:'✓';
    color:var(--rl-accent);
    margin-right:9px
}

.rl-coming {
    display:inline-flex;
    align-items:center;
    padding:6px 12px;
    border-radius:8px;
    background:var(--rl-paper);
    border:1px solid var(--rl-line);
    font-size:12px;
    font-weight:750;
    color:var(--rl-accent)
}

.rl-book {
    padding:18px 17px;
    border-radius:3px 12px 12px 3px;
    background:linear-gradient(145deg,#1447e6,#7008e7);
    color:#fff;
    box-shadow:9px 11px 0 -4px #c2b6df,0 17px 30px -13px #2f1f66a8;
    transform:rotate(6deg);
    border-left:5px solid #ffffff20
}

.rl-book>span {
    font-size:7px;
    letter-spacing:.13em;
    line-height:1.7;
    display:block;
    color:#dfd5fa
}

.rl-book-art {
    display:block;
    width:100%;
    height:78px;
    margin:15px 0;
    stroke:#dbeafe;
    stroke-width:2;
    stroke-linecap:round;
    stroke-linejoin:round;
}

.rl-book>strong {
    font-size:20px;
    line-height:1.15;
    display:block;
    letter-spacing:-.03em
}

.rl-book>small {
    display:block;
    font-size:7px;
    margin-top:17px;
    color:#dfd5fa
}

.rl-bottom {
    display:flex;
    align-items:center;
    justify-content:space-between;
    gap:20px;
    margin-top:35px
}

.rl-bottom p {
    font-size:12px;
    color:var(--rl-muted)
}

.rl-sr-only {
    position:absolute;
    width:1px;
    height:1px;
    padding:0;
    margin:-1px;
    overflow:hidden;
    clip:rect(0,0,0,0);
    white-space:nowrap;
    border:0
}

.rl-walkthrough {
    padding:24px;
    margin:24px 0;
    background:var(--rl-paper);
    border:1px solid var(--rl-line);
    border-radius:20px;
    box-shadow:0 10px 30px -28px #1447e6;
}

.rl-player-top,.rl-trainer-top,.rl-trainer-navigation,.rl-player-controls {
    display:flex;
    align-items:center;
    justify-content:space-between;
    gap:12px;
}

.rl-player-counter {
    font-size:11px;
    font-weight:700;
    color:var(--rl-muted);
}

.rl-player-equation {
    font-size:22px;
    font-weight:800;
    margin:14px 0;
    color:var(--rl-accent);
    overflow-wrap:anywhere;
}

.rl-player-select:empty {
    display:none;
}

.rl-player-select label {
    display:flex;
    gap:12px;
    align-items:center;
    flex-wrap:wrap;
    font-size:12px;
    color:var(--rl-muted);
    margin-bottom:15px;
}

.rl-player-select select {
    border:1px solid var(--rl-line);
    border-radius:10px;
    background:var(--rl-bg);
    color:var(--rl-text);
    padding:8px 30px 8px 12px;
}

.rl-player-step {
    padding:20px;
    border-radius:14px;
    background:var(--rl-soft);
    min-height:230px;
}

.rl-player-title {
    display:block;
    color:var(--rl-accent);
    font-size:11px;
    font-weight:750;
}

.rl-player-expression {
    display:block;
    font-size:20px;
    margin:10px 0;
    line-height:1.55;
    overflow-wrap:anywhere;
}

.rl-player-detail {
    font-size:14px;
    color:var(--rl-text);
    line-height:1.9;
    margin:0;
}

.rl-player-notes {
    list-style:decimal;
    padding-left:22px;
    margin:16px 0 0;
    font-size:13px;
    line-height:1.9;
    color:var(--rl-text);
}

.rl-player-notes li+li { margin-top:10px; }
.rl-player-notes:empty,.rl-player-grouping:empty,.rl-player-bits:empty { display:none; }
.rl-player-grouping { margin:18px 0; }
.rl-player-grouping>p,.rl-player-bits caption {
    font-size:12px;
    color:var(--rl-muted);
    text-align:left;
    margin:0 0 8px;
}
.rl-group-row { display:flex; gap:10px; flex-wrap:wrap; }
.rl-group {
    display:inline-flex;
    padding:8px 12px;
    border:1px solid var(--rl-line);
    border-radius:10px;
    background:var(--rl-paper);
    font:700 20px/1.5 ui-monospace,monospace;
    letter-spacing:2px;
}
.rl-group.is-active { border:2px solid var(--rl-accent); padding:7px 11px; color:var(--rl-accent); }
.rl-group .is-padding { color:var(--rl-muted); text-decoration:underline dotted; text-underline-offset:5px; }
.rl-player-bits table { width:100%; border-collapse:collapse; margin:16px 0; table-layout:fixed; font-size:13px; }
.rl-player-bits th,.rl-player-bits td { padding:9px 4px; border:1px solid var(--rl-line); text-align:center; overflow-wrap:anywhere; }
.rl-player-bits th { width:82px; font-size:12px; font-weight:600; text-align:left; padding-left:8px; }
.rl-player-bits td { background:var(--rl-paper); font-variant-numeric:tabular-nums; }
.rl-player-bits td.is-on { background:var(--rl-soft); color:var(--rl-accent); font-weight:800; }
.rl-player-help { font-size:12px; line-height:1.8; color:var(--rl-muted); margin:14px 0 0; }
.rl-explain-list { list-style:decimal; padding-left:22px; margin:18px 0; font-size:14px; line-height:1.9; }
.rl-explain-list li+li { margin-top:12px; }
.rl-number-key { display:flex; flex-wrap:wrap; gap:8px; margin:18px 0; }
.rl-number-key span { background:var(--rl-soft); border:1px solid var(--rl-line); border-radius:9px; padding:9px 12px; font-size:13px; }
.rl-route-note { background:var(--rl-soft); padding:20px; border-radius:14px; margin:20px 0; }
.rl-route-note p { font-size:14px; line-height:1.9; margin:8px 0; }

.rl-player-result {
    display:flex;
    align-items:center;
    justify-content:space-between;
    gap:16px;
    border-top:1px solid var(--rl-line);
    margin-top:16px;
    padding-top:14px;
}

.rl-player-result>span {
    font-size:10px;
    color:var(--rl-muted);
}

.rl-player-result strong {
    font-size:25px;
    color:var(--rl-accent);
    font-variant-numeric:tabular-nums;
    overflow-wrap:anywhere;
    min-width:0;
}

.rl-player-progress,.rl-trainer>progress {
    display:block;
    width:100%;
    height:6px;
    border:0;
    border-radius:6px;
    overflow:hidden;
    accent-color:#1447e6;
    background:var(--rl-line);
    margin:20px 0;
}

.rl-player-progress::-webkit-progress-bar,.rl-trainer>progress::-webkit-progress-bar {
    background:var(--rl-line);
}

.rl-player-progress::-webkit-progress-value,.rl-trainer>progress::-webkit-progress-value {
    background:linear-gradient(to right,#1447e6,#7008e7);
    transition:width .3s;
}

.rl-player-progress::-moz-progress-bar,.rl-trainer>progress::-moz-progress-bar {
    background:#1447e6;
}

.rl-player-controls button,.rl-trainer button {
    min-height:44px;
    justify-content:center;
}

.radix-lesson button:disabled {
    opacity:.45;
    cursor:default;
}

.rl-player-controls button {
    flex:1;
}

.rl-trainer {
    padding:26px;
    border:1px solid var(--rl-line);
    border-radius:24px;
    background:var(--rl-paper);
    margin-top:26px;
    box-shadow:0 15px 35px -30px #1447e655;
}

.rl-trainer-top strong {
    display:block;
    font-size:13px;
    margin-top:5px;
}

.rl-trainer-stats {
    display:grid;
    grid-template-columns:repeat(3,minmax(0,1fr));
    gap:12px;
    margin-top:24px;
}

.rl-trainer-stats>div {
    background:var(--rl-bg);
    padding:15px;
    border:1px solid var(--rl-line);
    border-radius:12px;
}

.rl-trainer-stats strong {
    display:block;
    font-size:22px;
    color:var(--rl-accent);
}

.rl-trainer-stats span {
    display:block;
    font-size:10px;
    line-height:1.7;
    color:var(--rl-muted);
}

.rl-question-nav {
    display:flex;
    justify-content:space-between;
    gap:10px;
    margin:20px 0;
}

.rl-question-nav button {
    flex:1;
    border:1px solid var(--rl-line);
    border-radius:10px;
    background:var(--rl-bg);
    color:var(--rl-muted);
    font-size:13px;
    font-weight:800;
}

.rl-question-nav button.is-solved {
    color:#15805d;
    border-color:#8ccbb6;
    background:#10b9810d;
}

.rl-question-nav button.is-solved::after {
    content:' ✓';
}

.rl-question-nav button[aria-current] {
    border-color:#1447e6;
    box-shadow:0 0 0 2px #1447e61a;
    color:var(--rl-accent);
    background:var(--rl-soft);
}

.rl-active-question {
    border:1px solid var(--rl-line);
    background:var(--rl-bg);
    padding:22px;
    border-radius:16px;
}

.rl-trainer-label {
    display:block;
    font-size:12px;
    color:var(--rl-muted);
    margin-top:14px;
}

.rl-question-equation {
    font-size:34px;
    font-weight:800;
    letter-spacing:-.03em;
    line-height:1.5;
    margin:12px 0 22px;
    overflow-wrap:anywhere;
}

.rl-question-equation>span:last-child {
    color:var(--rl-accent);
}

.rl-input-note {
    font-size:10px;
    color:var(--rl-muted);
    margin:12px 0 0;
    line-height:1.9;
}

.rl-help-actions {
    display:flex;
    flex-wrap:wrap;
    gap:8px 22px;
    margin:15px 0;
}

.rl-trainer-hint {
    font-size:12px;
    background:var(--rl-soft);
    padding:16px;
    border-left:3px solid var(--rl-accent);
    border-radius:0 10px 10px 0;
    margin:16px 0;
    line-height:1.9;
}

.rl-trainer-navigation {
    padding-top:20px;
    margin-top:20px;
    border-top:1px solid var(--rl-line);
}

@media(max-width:680px) {
    .rl-walkthrough,.rl-trainer {
        padding:16px;
    }
    .rl-player-step,.rl-active-question {
        padding:16px;
    }
    .rl-player-step {
        min-height:270px;
    }
    .rl-player-result {
        flex-direction:column;
        align-items:stretch;
        gap:8px;
    }
    .rl-player-result strong {
        align-self:flex-end;
        max-width:100%;
    }
    .rl-player-controls {
        flex-wrap:wrap;
        gap:8px;
    }
    .rl-player-controls [data-player-play] {
        order:-1;
        flex-basis:100%;
    }
    .rl-trainer-top {
        align-items:flex-start;
        flex-direction:column;
    }
    .rl-trainer-stats {
        gap:6px;
    }
    .rl-trainer-stats>div {
        padding:10px 8px;
    }
    .rl-trainer-stats strong {
        font-size:19px;
    }
    .rl-trainer-stats span {
        font-size:9px;
    }
    .rl-question-nav {
        gap:6px;
    }
    .rl-question-equation {
        font-size:26px;
    }
    .rl-trainer .rl-answer-row {
        flex-direction:column;
    }
    .rl-trainer .rl-answer-row input {
        width:100%;
    }
    .rl-trainer-navigation {
        gap:8px;
    }
    .rl-trainer-navigation button {
        flex:1;
        font-size:10px;
        padding:10px 8px;
    }
}

@media(min-width:1450px) {
    .rl-wrap {
        max-width:1260px
    }
    .rl-hero-layout {
        gap:90px
    }
    .rl-layout {
        gap:75px
    }
}

@media(max-width:900px) {
    .rl-hero-layout {
        gap:30px
    }
    .rl-hero h1 {
        font-size:34px
    }
    .rl-bit-card {
        padding:22px
    }
    .rl-equation {
        font-size:31px;
        gap:15px
    }
    .rl-layout {
        grid-template-columns:180px minmax(0,1fr);
        gap:30px
    }
    .rl-meta {
        gap:12px
    }
    .rl-base-grid {
        grid-template-columns:1fr 1fr
    }
    .rl-next {
        gap:23px;
        padding:25px;
        grid-template-columns:1fr 140px
    }
    .rl-book>strong {
        font-size:17px
    }
    .rl-lab-tag {
        display:none
    }
}

@media(max-width:680px) {
    .rl-wrap {
        padding:0 20px
    }
    .rl-hero-layout {
        grid-template-columns:1fr;
        padding:30px 0;
        gap:33px
    }
    .rl-hero h1 {
        font-size:32px
    }
    .rl-lead {
        font-size:13px
    }
    .rl-meta {
        font-size:9px;
        gap:12px
    }
    .rl-actions {
        gap:20px
    }
    .rl-bit-card {
        max-width:340px;
        width:100%;
        justify-self:center
    }
    .rl-equation {
        font-size:30px
    }
    .rl-layout {
        display:block;
        padding-top:0
    }
    .rl-sidebar {
        padding:16px 0 25px
    }
    .rl-sidebar-inner {
        position:static
    }
    .rl-sidebar-inner>.rl-eyebrow,.rl-sidebar-note {
        display:none
    }
    .rl-toc {
        display:grid;
        grid-template-columns:1fr 1fr;
        gap:5px;
        margin:0
    }
    .rl-toc a {
        font-size:10px;
        padding:8px 6px
    }
    .rl-toc a span {
        margin-right:6px
    }
    .rl-section {
        scroll-margin-top:85px;
        padding-bottom:30px;
        margin-bottom:31px
    }
    .rl-section h2 {
        font-size:22px
    }
    .rl-section-heading {
        gap:11px
    }
    .rl-section-heading .rl-eyebrow {
        font-size:8px
    }
    .rl-number {
        width:32px;
        height:38px;
        font-size:11px
    }
    .rl-section>p {
        font-size:14px
    }
    .rl-base-grid {
        gap:9px
    }
    .rl-lab {
        padding:18px
    }
    .rl-lab h3 {
        font-size:15px
    }
    .rl-switches {
        gap:8px
    }
    .rl-bit-switch {
        width:50px;
        min-height:68px
    }
    .rl-live-result {
        gap:10px;
        font-size:11px
    }
    .rl-live-result strong {
        font-size:23px
    }
    .rl-worked-header {
        padding:14px
    }
    .rl-worked-header>span {
        font-size:8px
    }
    .rl-worked th,.rl-worked td {
        padding:9px
    }
    .rl-worked-answer {
        padding:14px;
        font-size:10px
    }
    .rl-example-grid {
        gap:10px;
        grid-template-columns:1fr
    }
    .rl-example-grid article {
        padding:14px
    }
    .rl-example-grid h3 {
        font-size:22px
    }
    .rl-example-grid p {
        font-size:13px
    }
    .rl-answer-row {
        gap:8px
    }
    .rl-answer-row input {
        width:100px
    }
    .rl-next {
        grid-template-columns:1fr;
        padding:24px;
        gap:30px
    }
    .rl-next h2 {
        font-size:25px
    }
    .rl-book {
        width:155px;
        justify-self:center;
        margin:0 0 13px
    }
    .rl-bottom {
        flex-direction:column;
        align-items:stretch;
        gap:10px
    }
    .rl-bottom p {
        text-align:center
    }
}

@media(prefers-reduced-motion:reduce) {
    .radix-lesson * {
        transition:none!important;
        scroll-behavior:auto!important
    }
}

@media print {
    .rl-sidebar,.rl-actions,.rl-next,.rl-bottom,.rl-answer-row {
        display:none
    }
    .rl-wrap {
        padding:0;
        max-width:none
    }
    .rl-layout {
        display:block
    }
    .radix-lesson {
        background:white;
        color:black
    }
    .rl-section {
        break-inside:avoid
    }
    .rl-bit-card {
        box-shadow:none
    }
}