/* DigiPrep — shared lesson / notes list layout */

* {
    margin: 0;
    padding: 0;
    box-sizing: border-box;
    font-family: 'Open Sans', sans-serif;
}

.mainarea {
    /* header offset handled by site-chrome.css; background via page-shells */
    padding: 20px;
    padding-bottom: 40px;
    display: flex;
    flex-direction: column;
    gap: 20px;
    align-items: center;
    min-height: calc(100vh - var(--dp-header-height, 64px));
}

.mainarea > .dp-subject-back {
    align-self: center;
    width: 50%;
    box-sizing: border-box;
}

.lesson-list-intro {
    width: 50%;
    text-align: center;
    padding: 1.5rem 1.25rem 1.5rem;
    background-color: var(--dp-card-hover);
    border-radius: var(--dp-radius-sm);
    border: 1px solid var(--dp-border);
    box-shadow: var(--dp-shadow-card);
}

.lesson-list-intro__eyebrow {
    font-size: 0.8125rem;
    font-weight: 600;
    letter-spacing: 0.06em;
    text-transform: uppercase;
    color: var(--dp-muted);
    margin-bottom: 0.5rem;
}

.lesson-list-intro__title {
    font-size: 1.75rem;
    font-weight: 700;
    color: var(--dp-text);
    line-height: 1.2;
    letter-spacing: -0.02em;
}

.lesson-list-intro__desc {
    font-size: 0.9375rem;
    line-height: 1.5;
    color: var(--dp-text-soft);
    max-width: 28rem;
    margin-left: auto;
    margin-right: auto;
}

.lesson-list-intro + .chapter {
    margin-top: 10px;
}

/* ── Chapter card (same structure for 1 or many lessons) ── */

.chapter {
    background-color: var(--dp-card);
    padding: 1.25rem 1.25rem 1.35rem;
    border-radius: var(--dp-radius-sm);
    margin-top: 30px;
    width: 50%;
    align-self: center;
    border: 1px solid var(--dp-border);
    box-shadow: var(--dp-shadow-card);
    transition: border-color 0.2s ease, box-shadow 0.2s ease;
}

.chapter__head {
    display: flex;
    align-items: flex-start;
    justify-content: space-between;
    gap: 1rem;
    margin-bottom: 1rem;
    padding-bottom: 0.85rem;
    border-bottom: 1px solid var(--dp-border);
}

.chapter__title {
    font-size: 1.25rem;
    color: var(--dp-text);
    line-height: 1.35;
    font-weight: 600;
    text-align: left;
}

.chapter__progress {
    flex-shrink: 0;
    font-size: 0.75rem;
    font-weight: 600;
    letter-spacing: 0.03em;
    text-transform: uppercase;
    color: var(--dp-muted);
    white-space: nowrap;
    padding-top: 0.15rem;
}

.chapter__progress[hidden] {
    display: none;
}

.chapter__lessons {
    list-style: none;
    display: grid;
    grid-template-columns: repeat(2, minmax(0, 1fr));
    gap: 0.75rem;
}

.chapter__lessons:has(> .chapter__lesson:only-child) {
    grid-template-columns: 1fr;
}

.lesson-link {
    display: flex;
    align-items: center;
    justify-content: space-between;
    gap: 0.65rem;
    min-height: 3rem;
    padding: 0.75rem 0.85rem;
    background-color: var(--dp-fill-subtle);
    border: 1px solid var(--dp-border);
    border-radius: var(--dp-radius-sm);
    color: var(--dp-text);
    text-decoration: none;
    font-size: 0.875rem;
    font-weight: 600;
    line-height: 1.4;
    text-align: left;
    transition: background-color 0.25s ease, border-color 0.25s ease, transform 0.15s ease;
}

.lesson-link:hover,
.lesson-link:active,
.lesson-link:focus-visible {
    background-color: var(--dp-fill-hover);
    border-color: var(--dp-text);
    transform: translateY(-2px);
}

.lesson-link:active {
    transform: translateY(0);
}

.lesson-link:focus-visible {
    outline: none;
}

.lesson-link.is-complete:hover,
.lesson-link.is-complete:active,
.lesson-link.is-complete:focus-visible {
    background-color: var(--dp-lesson-complete-hover);
    border-color: rgba(96, 165, 250, 0.75);
}

.lesson-link__label {
    flex: 1;
    min-width: 0;
}

.lesson-link__status {
    flex-shrink: 0;
    min-width: 2.85rem;
    padding: 0.2rem 0.45rem;
    border-radius: 999px;
    border: 1px solid var(--dp-border-strong);
    background-color: transparent;
    font-size: 0.75rem;
    font-weight: 700;
    line-height: 1.2;
    color: var(--dp-muted);
    text-align: center;
}

/* Completed quiz: blue lesson button */
.lesson-link.is-complete {
    border-color: var(--dp-lesson-complete-border);
    background-color: var(--dp-lesson-complete-bg);
}

.lesson-link.is-complete .lesson-link__status {
    border-color: rgba(96, 165, 250, 0.45);
    color: var(--dp-text-soft);
    background-color: rgba(56, 132, 255, 0.12);
}

@media (max-width: 640px) {
    .mainarea > .dp-subject-back,
    .lesson-list-intro,
    .chapter {
        width: 92%;
    }

    .chapter {
        margin-top: 20px;
    }

    .lesson-list-intro + .chapter {
        margin-top: 0;
    }

    .chapter__lessons {
        grid-template-columns: 1fr;
    }

    .chapter__head {
        flex-direction: column;
        align-items: flex-start;
        gap: 0.35rem;
    }
}