.learn-hero {
    padding: clamp(5.5rem, 10vw, 9rem) 0 clamp(4rem, 7vw, 6rem);
    border-bottom: 1px solid var(--line);
}

.learn-hero-grid {
    display: grid;
    grid-template-columns: minmax(0, 1.15fr) minmax(320px, 0.85fr);
    align-items: end;
    gap: clamp(3rem, 8vw, 7rem);
}

.learn-hero h1 {
    max-width: 780px;
    font-size: clamp(3.8rem, 8vw, 7rem);
}

.learn-hero-copy {
    padding-top: 1.4rem;
    border-top: 2px solid var(--ink);
}

.learn-hero-copy .lede {
    margin-top: 0;
}

.learn-proof {
    border-bottom: 1px solid var(--line);
    background: var(--white);
}

.learn-proof-grid {
    display: grid;
    grid-template-columns: repeat(4, minmax(0, 1fr));
}

.learn-proof-grid > div {
    min-height: 140px;
    padding: 2rem;
    border-bottom: 3px solid transparent;
}

.learn-proof-grid > div:nth-child(1) {
    border-color: var(--accent);
}

.learn-proof-grid > div:nth-child(2) {
    border-color: var(--teal);
}

.learn-proof-grid > div:nth-child(3) {
    border-color: var(--gold);
}

.learn-proof-grid > div:nth-child(4) {
    border-color: var(--violet);
}

.learn-proof-grid strong,
.learn-proof-grid span {
    display: block;
}

.learn-proof-grid strong {
    font-size: clamp(2rem, 4vw, 3.1rem);
    font-weight: 400;
    letter-spacing: -0.05em;
    line-height: 1;
}

.learn-proof-grid span {
    margin-top: 0.65rem;
    color: var(--muted);
    font-family: var(--mono);
    font-size: 0.7rem;
    letter-spacing: 0.05em;
    text-transform: uppercase;
}

.learn-library {
    padding: clamp(5rem, 9vw, 8.5rem) 0;
}

.learn-section-heading {
    margin-bottom: clamp(2.5rem, 5vw, 4rem);
}

.learn-shell {
    display: grid;
    grid-template-columns: minmax(280px, 0.72fr) minmax(0, 1.75fr);
    align-items: start;
    gap: clamp(1.5rem, 3vw, 3rem);
}

.learn-curriculum {
    position: sticky;
    top: 6.5rem;
    max-height: calc(100vh - 8rem);
    overflow: auto;
    border-top: 2px solid var(--ink);
    border-bottom: 1px solid var(--line);
    background: var(--white);
}

.learn-course-tabs {
    display: grid;
}

.learn-course-tab {
    display: grid;
    grid-template-columns: 2rem minmax(0, 1fr);
    gap: 0.7rem;
    align-items: center;
    width: 100%;
    padding: 1rem 1.1rem;
    border: 0;
    border-bottom: 1px solid var(--line);
    background: transparent;
    color: var(--ink);
    cursor: pointer;
    font-size: 0.88rem;
    font-weight: 600;
    text-align: left;
}

.learn-course-tab span {
    color: var(--accent);
    font-family: var(--mono);
    font-size: 0.7rem;
    font-weight: 400;
}

.learn-course-tab:hover,
.learn-course-tab[aria-selected="true"] {
    background: var(--paper-deep);
}

.learn-course-tab[aria-selected="true"] {
    box-shadow: inset 0 -3px 0 var(--accent);
}

.learn-curriculum-head {
    padding: 1.3rem 1.1rem;
    background: var(--ink);
    color: var(--white);
}

.learn-curriculum-head strong,
.learn-curriculum-head span {
    display: block;
}

.learn-curriculum-head strong {
    font-size: 0.94rem;
    line-height: 1.35;
}

.learn-curriculum-head span {
    margin-top: 0.35rem;
    color: rgba(255, 255, 255, 0.64);
    font-family: var(--mono);
    font-size: 0.68rem;
}

.learn-lesson-list {
    display: grid;
}

.learn-lesson-button {
    display: grid;
    grid-template-columns: 1.7rem minmax(0, 1fr) auto;
    gap: 0.65rem;
    align-items: start;
    width: 100%;
    padding: 0.9rem 1.1rem;
    border: 0;
    border-bottom: 1px solid var(--line);
    background: transparent;
    color: var(--ink);
    cursor: pointer;
    text-align: left;
}

.learn-lesson-button:hover,
.learn-lesson-button[aria-current="true"] {
    background: var(--sky);
}

.learn-lesson-button[aria-current="true"] {
    box-shadow: inset 0 -3px 0 var(--accent);
}

.learn-lesson-index,
.learn-lesson-duration {
    color: var(--muted);
    font-family: var(--mono);
    font-size: 0.65rem;
}

.learn-lesson-title {
    font-size: 0.82rem;
    font-weight: 500;
    line-height: 1.35;
}

.learn-viewer {
    min-width: 0;
    border-top: 2px solid var(--ink);
    border-bottom: 1px solid var(--line);
    background: var(--white);
}

.learn-video-frame {
    position: relative;
    aspect-ratio: 16 / 9;
    background: var(--ink);
}

.learn-video-frame iframe {
    display: block;
    width: 100%;
    height: 100%;
    border: 0;
}

.learn-video-copy {
    padding: clamp(1.7rem, 4vw, 3rem);
}

.learn-video-kicker {
    color: var(--accent);
    font-family: var(--mono);
    font-size: 0.72rem;
    letter-spacing: 0.06em;
    text-transform: uppercase;
}

.learn-video-copy h3 {
    max-width: 760px;
    margin-top: 0.8rem;
    font-size: clamp(1.7rem, 3.5vw, 3rem);
}

.learn-video-copy p {
    max-width: 760px;
    color: var(--muted);
}

.learn-video-actions {
    display: flex;
    flex-wrap: wrap;
    gap: 1.5rem;
    margin-top: 1.5rem;
}

.learn-context {
    padding: clamp(4rem, 8vw, 7rem) 0;
    background: var(--moss);
    color: var(--white);
}

.learn-context-grid {
    display: grid;
    grid-template-columns: minmax(0, 0.8fr) minmax(0, 1.2fr);
    gap: clamp(3rem, 8vw, 7rem);
}

.learn-context h2 {
    color: var(--white);
}

.learn-context-grid > div:last-child {
    padding-top: 1.2rem;
    border-top: 1px solid var(--line-light);
}

.learn-context-grid > div:last-child p {
    color: rgba(255, 255, 255, 0.75);
}

@media (max-width: 1000px) {
    .learn-hero-grid,
    .learn-context-grid {
        grid-template-columns: 1fr;
    }

    .learn-shell {
        grid-template-columns: minmax(240px, 0.7fr) minmax(0, 1.3fr);
    }

    .learn-proof-grid {
        grid-template-columns: repeat(2, minmax(0, 1fr));
    }
}

@media (max-width: 720px) {
    .learn-hero {
        padding-top: 4.5rem;
    }

    .learn-hero h1 {
        font-size: clamp(3.2rem, 15vw, 5rem);
    }

    .learn-proof-grid {
        grid-template-columns: 1fr 1fr;
    }

    .learn-proof-grid > div {
        min-height: 120px;
        padding: 1.25rem 0.75rem;
    }

    .learn-shell {
        grid-template-columns: 1fr;
    }

    .learn-viewer {
        grid-row: 1;
    }

    .learn-curriculum {
        position: static;
        grid-row: 2;
        max-height: none;
    }

    .learn-course-tab {
        padding: 0.9rem;
    }

    .learn-video-copy {
        padding: 1.4rem;
    }
}