/* Learning: landing, fieldbook shelf header, case library, cases.
   Uses the site tokens from style.css. Chart colours (#1f6f9a, #c4622d) were
   checked with the dataviz palette validator against a light surface. */

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

.crumbs {
    font-size: 1.3rem;
    color: var(--text-muted);
    margin-top: 2.4rem;
    margin-bottom: 0.4rem;
}
.crumbs a { color: var(--text-secondary); border-bottom: 1px solid var(--link-underline); }

.shelf-heading {
    font-size: 1.3rem;
    font-weight: 700;
    letter-spacing: 0.08em;
    text-transform: uppercase;
    color: var(--text-muted);
    margin: 4rem 0 1.2rem;
}

/* Landing: two shelves */
.shelves {
    display: grid;
    grid-template-columns: 1fr 1fr;
    gap: 1.6rem;
    margin: 2.4rem 0 3.2rem;
}
.shelf {
    position: relative;
    display: flex;
    flex-direction: column;
    gap: 0.8rem;
    padding: 2.4rem 2.4rem 2rem;
    background: var(--bg-card);
    border: 1px solid var(--border);
    border-radius: 8px;
    transition: border-color 0.15s ease;
}
.shelf:hover { border-color: var(--border-hover); opacity: 1; }
.shelf:focus-visible { outline: 2px solid var(--text); outline-offset: 2px; }
.shelf__label {
    font-size: 1.2rem; letter-spacing: 0.08em; text-transform: uppercase; color: var(--text-muted);
}
.shelf h2 { font-size: 2.4rem; line-height: 1.15; letter-spacing: -0.02em; color: var(--text); }
.shelf p { font-size: 1.5rem; color: var(--text-body); }
.shelf__count { margin-top: auto; padding-top: 1rem; font-size: 1.3rem; color: var(--text-secondary); }
.shelf__arrow { position: absolute; right: 2rem; bottom: 1.8rem; color: var(--text-muted); }
.learning-note { max-width: 62ch; }

/* Concept and case lists */
.concept-list, .case-list { list-style: none; border-top: 1px solid var(--border); }
.concept-row, .case-row { border-bottom: 1px solid var(--border); }
.concept-row > a, .case-row > a, .concept-row:not(.concept-row--live), .case-row:not(.case-row--built) {
    display: grid; grid-template-columns: 1fr auto; gap: 1.6rem; align-items: baseline; padding: 1.6rem 0;
}
.concept-row--live > a, .case-row--built > a { padding: 1.6rem 0; }
.concept-row h3, .case-row h3 { font-size: 1.8rem; line-height: 1.25; color: var(--text); }
.concept-row p, .case-row p { font-size: 1.4rem; color: var(--text-secondary); margin-top: 0.3rem; }
.concept-row__count, .case-row__status {
    font-size: 1.2rem; letter-spacing: 0.06em; text-transform: uppercase; color: var(--text-muted); white-space: nowrap;
}
.concept-row:not(.concept-row--live) h3, .case-row:not(.case-row--built) h3 { color: var(--text-secondary); font-weight: 500; }
.case-row--built .case-row__status, .concept-row--live .concept-row__count { color: var(--text); font-weight: 700; }
.case-foot { font-size: 1.3rem; color: var(--text-muted); margin-top: 1.6rem; }
.ledger-box { margin-top: 3.2rem; padding: 1.6rem 2rem; border: 1px solid var(--border); border-radius: 8px; background: var(--bg-card); font-size: 1.5rem; }
.ledger-box .shelf-heading { margin-top: 0; }

/* Case page */
.case-meta {
    display: grid; grid-template-columns: repeat(auto-fit, minmax(150px, 1fr)); gap: 1.2rem 2rem;
    margin-top: 2rem; padding: 1.6rem 0 0; border-top: 1px solid var(--border);
}
.case-meta dt { font-size: 1.1rem; letter-spacing: 0.08em; text-transform: uppercase; color: var(--text-muted); }
.case-meta dd { font-size: 1.4rem; color: var(--text); }

.case-body h2 {
    font-size: 1.3rem; font-weight: 700; letter-spacing: 0.08em; text-transform: uppercase;
    color: var(--text-muted); margin: 3.6rem 0 1.2rem;
}
.case-body hr { border: 0; border-top: 1px solid var(--border); margin: 3.2rem 0 0; }
.case-body p, .case-body li { font-size: 1.6rem; }
.case-body p + p, .case-body ul, .case-body ol { margin-top: 1.2rem; }
.case-body ul, .case-body ol { padding-left: 2rem; }
.case-body li + li { margin-top: 0.6rem; }
.case-body a { border-bottom: 1px solid var(--link-underline); }
.case-body h3 { font-size: 1.8rem; color: var(--text); margin: 2rem 0 0.8rem; }
.case-body h4 { font-size: 1.5rem; color: var(--text); margin: 1.6rem 0 0.6rem; }

.src { display: block; font-size: 1.2rem; color: var(--text-muted); margin-top: 0.3rem; }
.case-snapshot .src, .case-ledger .src { display: block; }

/* Tables */
.case-table-wrap { overflow-x: auto; margin: 1.6rem 0; -webkit-overflow-scrolling: touch; }
.case-table { width: 100%; border-collapse: collapse; font-size: 1.4rem; }
.case-table caption { text-align: left; font-size: 1.2rem; color: var(--text-muted); padding-bottom: 0.8rem; }
.case-table th, .case-table td { padding: 0.9rem 1rem 0.9rem 0; border-bottom: 1px solid var(--border); vertical-align: top; text-align: left; }
.case-table thead th { font-size: 1.1rem; letter-spacing: 0.06em; text-transform: uppercase; color: var(--text-muted); font-weight: 700; }
.case-table tbody th { font-weight: 500; color: var(--text); }
.case-table .num { text-align: right; font-variant-numeric: tabular-nums; padding-right: 1.6rem; white-space: nowrap; }
.case-table tr.is-derived th, .case-table tr.is-derived td { color: var(--text-secondary); font-style: italic; }
.grade { font-size: 1.1rem; letter-spacing: 0.06em; text-transform: uppercase; color: var(--text-muted); }
.grade--filed { color: var(--text); font-weight: 700; }
.case-ledger th { width: 20%; }
.case-ledger td:last-child { width: 22%; }
.case-cues td:first-child { width: 11%; }

.verdict, .weight { display: inline-block; font-size: 1.2rem; font-weight: 700; }
.verdict--contradicted { color: #9a3d12; }
.verdict--unverified { color: var(--text-secondary); }
.verdict--supported { color: #1f6f9a; }
.weight { letter-spacing: 0.06em; text-transform: uppercase; color: var(--text-muted); }
.weight--high { color: var(--text); }

/* Snapshot list */
.case-snapshot { margin: 1.2rem 0; border-top: 1px solid var(--border); }
.case-snapshot > div { display: grid; grid-template-columns: 22ch 1fr; gap: 1.6rem; padding: 0.9rem 0; border-bottom: 1px solid var(--border); font-size: 1.4rem; }
.case-snapshot dt { color: var(--text-muted); }
.case-snapshot dd { color: var(--text); }

/* Chart */
.case-figure { margin: 2.4rem 0; }
.case-figure svg { width: 100%; height: auto; display: block; }
.case-figure figcaption { font-size: 1.2rem; color: var(--text-muted); margin-top: 0.8rem; }

/* Drill */
.drill { margin: 1.6rem 0; padding: 2rem; background: var(--bg-card); border: 1px solid var(--border); border-radius: 8px; }
.drill fieldset { border: 0; margin: 0 0 2rem; padding: 0; min-width: 0; }
.drill legend { font-size: 1.5rem; font-weight: 700; color: var(--text); margin-bottom: 0.8rem; padding: 0; }
.drill .opt { display: flex; gap: 0.9rem; align-items: flex-start; padding: 0.5rem 0; font-size: 1.5rem; line-height: 1.4; cursor: pointer; }
.drill .opt input { margin-top: 0.35rem; flex: none; }
.drill label[for] { display: block; font-size: 1.5rem; margin-bottom: 0.6rem; }
.drill input[type=number] {
    width: 10rem; padding: 0.7rem 1rem; font: inherit; font-size: 1.6rem; color: var(--text);
    background: var(--bg); border: 1px solid var(--border-hover); border-radius: 6px;
}
.drill input:focus-visible { outline: 2px solid var(--text); outline-offset: 2px; }
.drill .knew { color: var(--text-secondary); font-size: 1.4rem; }
.drill-error { color: #9a3d12; font-size: 1.4rem; margin: 1rem 0 0; }
.drill-button {
    margin-top: 1.2rem; padding: 1rem 2rem; font: inherit; font-size: 1.5rem; font-weight: 700;
    color: var(--bg); background: var(--text); border: 0; border-radius: 6px; cursor: pointer;
}
.drill-button:hover { opacity: 0.88; }
.drill-button:focus-visible { outline: 2px solid var(--text); outline-offset: 3px; }
.drill-prior { margin-top: 1.2rem; font-size: 1.3rem; color: var(--text-muted); }
.drill-result { margin: 2rem 0; padding: 2rem; border: 1px solid var(--border-hover); border-radius: 8px; }
.drill-result h3 { margin-top: 0; }
.drill-result p, .drill-result li { font-size: 1.5rem; }
.drill-result ul { padding-left: 2rem; margin: 0.8rem 0; }
.drill-note { color: var(--text-muted); font-size: 1.3rem; }

.case-sources { padding-left: 2rem; }
.case-sources li { font-size: 1.4rem; }
.case-reveal[hidden], .drill-result[hidden], .ledger-box[hidden], .drill-error[hidden], .drill-prior[hidden] { display: none; }

@media (max-width: 640px) {
    .shelves { grid-template-columns: 1fr; }
    .case-snapshot > div { grid-template-columns: 1fr; gap: 0.2rem; }
    .case-ledger th, .case-ledger td:last-child, .case-cues td:first-child { width: auto; }
    .concept-row > a, .case-row > a { grid-template-columns: 1fr; gap: 0.4rem; }
    .concept-row:not(.concept-row--live), .case-row:not(.case-row--built) { grid-template-columns: 1fr; gap: 0.4rem; }
}