.relation-page .step-tabs { grid-template-columns: repeat(8, minmax(92px, 1fr)); }
.relation-page .step-tab:disabled { opacity: .52; cursor: not-allowed; transform: none; }
.relation-page .data-status[hidden] { display: none !important; }
.table-excerpts, .key-comparison { display: grid; grid-template-columns: repeat(2, minmax(0, 1fr)); gap: 16px; margin-bottom: 20px; }
.table-excerpts .table-shell, .key-comparison .table-shell { min-width: 0; margin-bottom: 0; }
.relation-data-table { min-width: 520px; }
.assignment-heading { margin: 4px 0 12px; color: #1b426f; font-size: 1rem; }
.record-assignment { display: grid; grid-template-columns: repeat(2, minmax(0, 1fr)); gap: 14px; margin-bottom: 22px; }
.assignment-row { display: grid; grid-template-columns: minmax(120px, .65fr) minmax(180px, 1fr); align-items: center; gap: 12px; padding: 13px 15px; border: 1px solid var(--db-line); border-radius: 12px; background: #fff; }
.assignment-row span, .assignment-row small { display: block; }
.assignment-row strong { color: #1b426f; }
.assignment-row small { margin-top: 3px; color: #0f5a90; font-family: "SFMono-Regular", Consolas, monospace; font-weight: 800; }
.assignment-row select, .task-card select { width: 100%; padding: 10px; border: 1px solid #b8c7d9; border-radius: 9px; background: #fff; color: var(--db-ink); font: inherit; }
.assignment-row.is-correct { border-color: #73c8aa; background: #f2fff9; }
.assignment-row.is-wrong { border-color: #edb4bc; background: #fff8f8; }
.relation-concept { display: block; }
.relation-concept[hidden] { display: none; }
.relationship-copy { margin-bottom: 20px; }
.foreign-key-reveal { margin-top: 20px; padding: 20px; border: 1px solid #a4d7c4; border-left: 5px solid #15956b; border-radius: 14px; background: #effdf8; color: #1d5543; }
.foreign-key-reveal strong { color: #096d50; font-size: 1.08rem; }
.foreign-key-reveal p { margin: 8px 0 0; line-height: 1.5; }
.inline-input { max-width: 130px; padding: 8px 10px; border: 1px solid #b8c7d9; border-radius: 8px; font: inherit; }
.uml-relationship, .cardinality-demo, .relation-diagram { display: flex; align-items: stretch; justify-content: center; margin: 24px 0; }
.diagram-class-card { width: min(100%, 245px); z-index: 1; }
.empty-class-body { min-height: 48px; background: #fff; }
.association-connector { position: relative; display: flex; align-items: center; justify-content: space-between; width: min(25vw, 190px); margin: 0 -1px; color: #1f4e7e; font-family: "SFMono-Regular", Consolas, monospace; font-weight: 900; text-align: center; }
.association-connector i { position: absolute; inset: 50% 0 auto; display: block; height: 2px; background: #526a84; transform: translateY(-50%); }
.association-connector label, .association-connector span { z-index: 2; margin: 0 7px; background: #fff; }
.fixed-cardinalities span { min-width: 24px; padding: 2px 4px; font-size: 1.05rem; }
.cardinality-gap input { width: 42px; height: 42px; box-sizing: border-box; border: 2px solid #3b6ea5; border-radius: 7px; background: #fff; color: #17324d; font: inherit; font-size: 1.05rem; font-weight: 900; text-align: center; text-transform: lowercase; }
.cardinality-gap input::placeholder { color: #6b7c90; opacity: 1; }
.cardinality-gap input:focus { outline: 3px solid rgba(59, 110, 165, .24); outline-offset: 2px; }
.summary-key-points { display: grid; grid-template-columns: repeat(3, minmax(0, 1fr)); gap: 14px; }
.summary-key-points article { padding: 18px; border: 1px solid var(--db-line); border-top: 5px solid #1d78a0; border-radius: 14px; background: #fbfdff; }
.summary-key-points h3 { margin: 0 0 10px; color: #174a80; font-size: 1rem; }
.summary-key-points p { margin: 0; color: var(--db-muted); line-height: 1.48; }
.summary-key-points code { display: inline-block; margin-bottom: 10px; color: #126f56; font-weight: 900; overflow-wrap: anywhere; }
.summary-actions .secondary-button { display: inline-flex; align-items: center; text-decoration: none; }
.solution-download { margin-top: 26px; padding: 20px 22px; border: 1px solid var(--db-line); border-left: 5px solid var(--db-blue); border-radius: 8px; background: white; box-shadow: 0 2px 8px rgba(30, 52, 85, 0.06); }
.solution-download h2 { margin: 0; color: #174a80; font-size: 1.15rem; }
.solution-reveal { margin-top: 13px; }
.solution-reveal summary { width: fit-content; cursor: pointer; color: #174a80; font-weight: 800; }
.solution-reveal[open] summary { margin-bottom: 14px; }
.solution-code-form { display: grid; gap: 9px; max-width: 520px; }
.solution-code-form label { color: var(--db-ink); font-weight: 700; }
.solution-code-controls { display: flex; flex-wrap: wrap; gap: 10px; align-items: center; }
.solution-code-controls input { width: 170px; padding: 10px 12px; border: 1px solid #b8c7d9; border-radius: 6px; color: var(--db-ink); font: inherit; letter-spacing: .08em; text-transform: uppercase; }
.solution-code-message { min-height: 1.3em; margin: 0; color: #0b7053; font-weight: 700; }
.solution-code-message.error { color: var(--db-red); }
.download-button { display: inline-flex; width: fit-content; align-items: center; gap: 8px; padding: 12px 18px; border-radius: 5px; background: var(--db-blue); color: white; font-weight: 800; text-decoration: none; }
.download-button:hover, .download-button:focus-visible { background: #104da9; outline: 3px solid rgba(23, 99, 213, .25); outline-offset: 2px; }
.download-button[hidden] { display: none; }
.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; }
@media (max-width: 760px) { .table-excerpts, .key-comparison, .record-assignment, .summary-key-points { grid-template-columns: 1fr; } .assignment-row { grid-template-columns: 1fr; } .uml-relationship, .cardinality-demo, .relation-diagram { flex-direction: column; align-items: center; } .association-connector { flex-direction: column; width: min(100%, 245px); height: 94px; margin: -1px 0; } .association-connector i { inset: 0 auto 0 50%; width: 2px; height: auto; transform: translateX(-50%); } .association-connector label, .association-connector span { margin: 7px 0; } }