.resource-grid {
    display: grid;
    gap: 14px;
    grid-template-columns: repeat(3, minmax(0, 1fr));
}

.resource-card {
    background: var(--parchment);
    border: 1px solid var(--parchment-dark);
    border-radius: 18px;
    display: flex;
    flex-direction: column;
    min-height: 330px;
    overflow: hidden;
}

.resource-card:nth-child(1) { --resource-accent: var(--green); }
.resource-card:nth-child(2) { --resource-accent: var(--blue); }
.resource-card:nth-child(3) { --resource-accent: var(--orange); }

.resource-card::before {
    background: var(--resource-accent);
    content: "";
    display: block;
    height: 7px;
}

.resource-card-head {
    padding: 22px 22px 14px;
}

.resource-step {
    color: var(--brown-light);
    font-size: 11px;
    font-weight: 800;
    letter-spacing: 0.12em;
}

.resource-card h3 {
    font-size: 19px;
    margin: 10px 0 8px;
}

.resource-card-head p,
.resource-empty {
    color: var(--brown-light);
    font-size: 13px;
    line-height: 1.65;
    margin: 0;
}

/* 教師館藏 opt-in：不影響共用 renderer 的學生版／其他資源列。 */
.library-reading { min-width: 0; }
.reading-note,
.reading-status,
.reading-actions,
.reading-preview { margin: 0; padding: 10px 22px; }
.reading-note,
.reading-status { color: var(--brown-light); font-size: 12px; line-height: 1.6; }
.reading-status:empty { padding-block: 0; }
.reading-list { list-style: none; margin: 0; padding: 0; }
.reading-item {
    border-top: 1px solid var(--parchment-dark);
    padding: 10px 22px;
    background: var(--parchment);
    overflow-wrap: anywhere;
}
.reading-item:hover,
.reading-item:focus-within { background: var(--parchment-dark); }
.reading-choice { display: grid; grid-template-columns: 18px minmax(0, 1fr); gap: 10px; cursor: pointer; }
.reading-choice input { width: 18px; height: 18px; margin: 2px 0 0; accent-color: var(--green); }
.reading-choice strong { font-size: 14px; line-height: 1.5; }
.reading-author,
.reading-no-link { margin: 4px 0 0 28px; color: var(--brown-light); font-size: 12px; }
.reading-link { display: inline-block; margin: 6px 0 0 28px; color: var(--green); text-decoration: underline; font-size: 13px; }
.reading-full-title { margin: 4px 0 0 28px; font-size: 12px; color: var(--brown-light); }
.reading-full-title p { margin: 6px 0; line-height: 1.5; }
.library-reading summary { cursor: pointer; padding-block: 6px; }
.reading-actions { border-top: 1px solid var(--parchment-dark); display: flex; flex-wrap: wrap; align-items: center; gap: 10px; }
.reading-count { font-size: 13px; }
.reading-copy,
.reading-select-all {
    min-height: 40px;
    padding: 8px 12px;
    border: 1px solid var(--green);
    border-radius: 6px;
    color: var(--green);
    background: var(--parchment);
    font: inherit;
    font-size: 13px;
    cursor: pointer;
}
.library-reading button:disabled { opacity: 0.5; cursor: not-allowed; }
.library-reading button:hover:not(:disabled) { background: var(--parchment-dark); }
.library-reading :is(input, a, button, summary, textarea):focus-visible { outline: 2px solid var(--green); outline-offset: 3px; }
.reading-preview { font-size: 13px; }
.reading-preview label { display: block; margin-block: 8px; }
.reading-preview textarea {
    box-sizing: border-box;
    width: 100%;
    display: block;
    margin-top: 6px;
    padding: 8px;
    font: inherit;
    line-height: 1.6;
    color: var(--brown-dark);
    background: var(--parchment);
    border: 1px solid var(--brown-light);
    border-radius: 4px;
    resize: vertical;
}

.resource-list {
    border-top: 1px solid var(--parchment-dark);
    display: grid;
    margin-top: auto;
}

.resource-item {
    color: var(--brown-dark);
    display: grid;
    gap: 4px;
    padding: 14px 22px;
    text-decoration: none;
}

.resource-item + .resource-item {
    border-top: 1px solid var(--parchment-dark);
}

a.resource-item:hover {
    background: rgba(20, 93, 67, 0.05);
}

.resource-item strong {
    font-size: 13px;
    line-height: 1.45;
}

.resource-item span {
    color: var(--brown-light);
    font-size: 11px;
}

.resource-empty {
    border-top: 1px solid var(--parchment-dark);
    margin-top: auto;
    padding: 22px;
}

.resource-skeleton {
    animation: pulse 1.2s ease-in-out infinite alternate;
    background: linear-gradient(100deg, #eeeee7, #faf9f4, #eeeee7);
    background-size: 200% 100%;
}

.student-signal-panel {
    align-items: start;
    border-top: 1px solid var(--parchment-dark);
    display: grid;
    gap: 20px;
    grid-template-columns: 54px minmax(0, 1fr);
    margin-top: 16px;
    padding: 34px 0;
}

.signal-icon {
    align-items: center;
    border: 1px solid var(--green);
    border-radius: 50%;
    color: var(--green);
    display: flex;
    font-size: 28px;
    height: 52px;
    justify-content: center;
}

.student-signal-panel h3 {
    font-size: 20px;
    margin: 8px 0;
}

.student-signal-panel p {
    color: var(--brown-light);
    line-height: 1.7;
    margin: 0;
}

.state-card {
    align-items: center;
    color: var(--brown-light);
    display: flex;
    gap: 12px;
    justify-content: center;
    min-height: 55vh;
}

.state-card-large {
    align-items: flex-start;
    flex-direction: column;
    margin: 0 auto;
    max-width: 1000px;
    min-height: calc(100vh - 150px);
}

.state-actions {
    display: flex;
    flex-wrap: wrap;
    gap: 12px;
    margin-top: 30px;
}

.primary-button,
.secondary-button {
    border-radius: 999px;
    display: inline-flex;
    font-weight: 750;
    justify-content: center;
    padding: 14px 22px;
    text-decoration: none;
}

.primary-button {
    background: var(--green);
    border: 1px solid var(--green);
    color: white;
    cursor: pointer;
}

.secondary-button {
    border: 1px solid var(--parchment-dark);
    color: var(--brown-dark);
}

.loading-mark {
    animation: spin 800ms linear infinite;
    border: 2px solid var(--parchment-dark);
    border-radius: 50%;
    border-top-color: var(--green);
    height: 22px;
    width: 22px;
}

footer {
    border-top: 1px solid var(--parchment-dark);
    color: var(--brown-light);
    display: flex;
    font-size: 12px;
    justify-content: space-between;
    margin: 0 clamp(20px, 5vw, 72px);
    padding: 24px 0 34px;
}

@keyframes spin { to { transform: rotate(360deg); } }
@keyframes pulse { to { background-position: -100% 0; } }

@media (max-width: 980px) {
    .dashboard-hero {
        grid-template-columns: 1fr;
    }

    .hero-orbit {
        display: none;
    }

    .metric-grid {
        grid-template-columns: repeat(2, 1fr);
    }

    .metric-note {
        grid-column: 1 / -1;
    }

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

    .course-rail {
        position: static;
    }

    .course-list {
        display: flex;
        margin: 0 -20px;
        overflow-x: auto;
        padding: 0 20px 12px;
    }

    .course-button {
        flex: 0 0 240px;
    }

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

    .resource-card {
        min-height: 240px;
    }
}

@media (max-width: 640px) {
    .teacher-header {
        min-height: 64px;
    }

    .brand img {
        height: 30px;
        width: 92px;
    }

    .brand-divider,
    .header-link,
    .brand-product,
    #userName {
        display: none;
    }

    .dashboard-hero {
        min-height: 300px;
        padding-top: 44px;
    }

    .dashboard-hero h1,
    .state-card h1 {
        font-size: 39px;
    }

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

    .metric-card {
        min-height: 130px;
        padding: 18px;
    }

    .metric-card strong {
        font-size: 38px;
    }

    .metric-note strong {
        font-size: 20px;
    }

    .course-title-panel {
        align-items: flex-start;
        flex-direction: column;
        gap: 26px;
    }

    .enrollment-pill {
        aspect-ratio: auto;
        border-radius: 999px;
        flex-direction: row;
        gap: 10px;
        min-width: 0;
        padding: 10px 17px;
    }

    .enrollment-pill strong {
        font-size: 24px;
    }

    .section-heading.horizontal {
        align-items: flex-start;
        flex-direction: column;
        gap: 14px;
    }

    footer {
        flex-direction: column;
        gap: 8px;
    }
}