:root {
    color-scheme: light;
    --ink: #17324d;
    --muted: #617386;
    --paper: #f7faf9;
    --surface: #ffffff;
    --line: #d9e4e2;
    --primary: #0f766e;
    --primary-dark: #0b5d57;
    --accent: #e8f5f1;
    --warning: #9a5b13;
    --warning-bg: #fff5dc;
    --shadow: 0 18px 45px rgba(23, 50, 77, 0.09);
}

* {
    box-sizing: border-box;
}

html {
    min-height: 100%;
    background: var(--paper);
}

body {
    min-height: 100vh;
    margin: 0;
    color: var(--ink);
    background:
        radial-gradient(circle at 90% 5%, rgba(15, 118, 110, 0.11), transparent 24rem),
        var(--paper);
    font-family: -apple-system, BlinkMacSystemFont, "Segoe UI", "Noto Sans TC", sans-serif;
    line-height: 1.65;
}

a {
    color: inherit;
}

.site-header {
    display: flex;
    align-items: center;
    justify-content: space-between;
    width: min(1120px, calc(100% - 40px));
    margin: 0 auto;
    padding: 24px 0;
}

.brand {
    font-size: 1.05rem;
    font-weight: 750;
    letter-spacing: 0.04em;
    text-decoration: none;
}

.brand:focus-visible,
.breadcrumb a:focus-visible {
    border-radius: 4px;
    outline: 3px solid var(--primary);
    outline-offset: 4px;
}

.status-chip,
.card-status {
    display: inline-flex;
    align-items: center;
    width: fit-content;
    border-radius: 999px;
    background: var(--accent);
    color: var(--primary-dark);
    font-size: 0.78rem;
    font-weight: 750;
    letter-spacing: 0.04em;
}

.status-chip {
    padding: 7px 12px;
}

.status-chip--warning,
.card-status {
    color: var(--warning);
    background: var(--warning-bg);
}

.page-shell {
    width: min(1120px, calc(100% - 40px));
    margin: 0 auto;
    padding: 72px 0 96px;
}

.hero {
    max-width: 760px;
    padding: 36px 0 88px;
}

.eyebrow,
.section-label {
    margin: 0 0 12px;
    color: var(--primary);
    font-size: 0.78rem;
    font-weight: 800;
    letter-spacing: 0.16em;
    text-transform: uppercase;
}

h1,
h2,
p {
    margin-top: 0;
}

h1 {
    max-width: 820px;
    margin-bottom: 22px;
    font-size: clamp(2.35rem, 7vw, 4.8rem);
    line-height: 1.08;
    letter-spacing: -0.045em;
}

h2 {
    margin-bottom: 10px;
    font-size: 1.25rem;
    line-height: 1.35;
}

.lead {
    max-width: 720px;
    margin-bottom: 30px;
    color: var(--muted);
    font-size: clamp(1rem, 2vw, 1.18rem);
}

.primary-link,
.secondary-link {
    display: inline-flex;
    align-items: center;
    gap: 10px;
    border-radius: 12px;
    font-weight: 750;
    text-decoration: none;
    transition: transform 160ms ease, background-color 160ms ease;
}

.primary-link {
    padding: 14px 20px;
    color: #fff;
    background: var(--primary);
    box-shadow: 0 10px 25px rgba(15, 118, 110, 0.2);
}

.primary-link:hover,
.primary-link:focus-visible {
    background: var(--primary-dark);
    transform: translateY(-2px);
}

.secondary-link {
    padding: 12px 0;
    color: var(--primary-dark);
}

.info-panel {
    display: grid;
    grid-template-columns: minmax(0, 1fr) minmax(0, 1fr);
    gap: 32px;
    padding: 30px;
    border: 1px solid var(--line);
    border-radius: 20px;
    background: rgba(255, 255, 255, 0.74);
    box-shadow: var(--shadow);
}

.info-panel p:last-child {
    margin-bottom: 0;
    color: var(--muted);
}

.hub-section {
    margin-top: 56px;
}

.section-heading {
    display: flex;
    align-items: end;
    justify-content: space-between;
    gap: 20px;
    margin-bottom: 20px;
}

.section-heading h2 {
    margin: 0;
    font-size: 1.55rem;
}

.hub-grid .feature-card {
    min-height: 235px;
}

.feature-card--static {
    cursor: default;
}

.feature-card--static:hover {
    border-color: var(--line);
    box-shadow: 0 8px 22px rgba(23, 50, 77, 0.05);
    transform: none;
}

.breadcrumb {
    display: flex;
    gap: 10px;
    margin-bottom: 55px;
    color: var(--muted);
    font-size: 0.92rem;
}

.breadcrumb a {
    color: var(--primary-dark);
    text-decoration: none;
}

.page-heading {
    margin-bottom: 48px;
}

.link-grid {
    display: grid;
    grid-template-columns: repeat(3, minmax(0, 1fr));
    gap: 18px;
}

.feature-card {
    display: flex;
    flex-direction: column;
    min-height: 260px;
    padding: 24px;
    border: 1px solid var(--line);
    border-radius: 18px;
    background: var(--surface);
    box-shadow: 0 8px 22px rgba(23, 50, 77, 0.05);
    text-decoration: none;
    transition: border-color 160ms ease, transform 160ms ease, box-shadow 160ms ease;
}

.feature-card:hover,
.feature-card:focus-visible {
    border-color: #8fc8c1;
    box-shadow: var(--shadow);
    transform: translateY(-3px);
}

.card-status {
    margin-bottom: 26px;
    padding: 5px 9px;
}

.feature-card p {
    color: var(--muted);
}

.card-link {
    margin-top: auto;
    color: var(--primary-dark);
    font-weight: 750;
}

.placeholder-shell {
    width: min(720px, calc(100% - 40px));
    margin: 0 auto;
    padding: min(16vh, 150px) 0 80px;
}

.placeholder-shell .card-status {
    margin-bottom: 34px;
}

.site-footer {
    width: min(1120px, calc(100% - 40px));
    margin: 0 auto;
    padding: 24px 0 34px;
    border-top: 1px solid var(--line);
    color: var(--muted);
    font-size: 0.86rem;
}

.auth-shell { width: min(540px, calc(100% - 40px)); margin: 0 auto; padding: 28px 0 56px; }
.auth-card, .query-panel, .results-panel { border: 1px solid var(--line); border-radius: 20px; background: var(--surface); box-shadow: var(--shadow); }
.auth-card { margin-top: 58px; padding: 32px; }
.auth-card h1 { font-size: clamp(2.2rem, 9vw, 3.3rem); }
.auth-form, .query-field { display: grid; gap: 7px; }
.auth-form { margin-top: 28px; }
.auth-form label, .query-field label { font-size: .9rem; font-weight: 750; }
.auth-form input, .query-field input, .query-field select { width: 100%; min-height: 44px; padding: 10px 12px; border: 1px solid #b9cac7; border-radius: 10px; color: var(--ink); background: #fff; font: inherit; }
.auth-form .primary-link, .query-actions .primary-link { justify-content: center; border: 0; cursor: pointer; font: inherit; }
.form-alert { margin: 22px 0 0; padding: 12px 14px; border: 1px solid #eccda3; border-radius: 10px; color: #80430c; background: #fff6e7; }
.account-bar { display: flex; align-items: center; gap: 12px; color: var(--muted); font-size: .9rem; }
.account-bar form { margin: 0; }
.text-button { padding: 0; border: 0; color: var(--primary-dark); background: transparent; font: inherit; cursor: pointer; }
.student-shell { padding-top: 38px; }
.query-panel { display: grid; grid-template-columns: repeat(3, minmax(0, 1fr)); gap: 18px; padding: 24px; }
.query-field--search { grid-column: span 2; }
.query-actions { display: flex; align-items: end; gap: 18px; }
.results-panel { margin-top: 26px; padding: 24px; }
.results-heading { display: flex; align-items: center; justify-content: space-between; gap: 18px; margin-bottom: 18px; }
.results-heading h2 { margin: 0; }
.results-heading strong { color: var(--primary-dark); }
.table-wrap { overflow-x: auto; }
table { width: 100%; min-width: 620px; border-collapse: collapse; text-align: left; }
th, td { padding: 13px 12px; border-bottom: 1px solid var(--line); white-space: nowrap; }
th { color: var(--muted); font-size: .82rem; letter-spacing: .04em; }
.status-label { padding: 4px 8px; border-radius: 999px; color: var(--primary-dark); background: var(--accent); font-size: .82rem; font-weight: 750; }
.empty-cell { padding: 34px; color: var(--muted); text-align: center; }

.proposal-shell { padding-top: 38px; }
.proposal-intro { display: flex; align-items: end; justify-content: space-between; gap: 32px; margin-bottom: 42px; }
.proposal-intro h1 { margin-bottom: 14px; font-size: clamp(2.5rem, 6vw, 4.3rem); }
.proposal-status { min-width: 190px; padding: 18px; border: 1px solid var(--line); border-radius: 16px; background: var(--surface); }
.proposal-status .card-status { margin-bottom: 9px; }
.proposal-status p { margin: 0; color: var(--muted); font-size: .88rem; }
.teacher-demo { padding: 28px; border-radius: 24px; color: #e8f5f1; background: #143b4a; box-shadow: 0 20px 48px rgba(19, 59, 74, .2); }
.demo-heading, .demo-card-heading { display: flex; align-items: center; justify-content: space-between; gap: 18px; }
.demo-heading { margin-bottom: 22px; }
.teacher-demo .section-label { color: #87d2c7; }
.teacher-demo h2, .teacher-demo h3, .teacher-demo h4 { color: #fff; }
.demo-heading h2 { margin: 0; font-size: 1.8rem; }
.demo-date { margin: 0; color: #b8cfcc; font-size: .9rem; }
.demo-overview-grid { display: grid; grid-template-columns: minmax(0, 1.35fr) minmax(280px, .8fr); gap: 18px; }
.demo-card { padding: 22px; border: 1px solid rgba(205, 239, 233, .18); border-radius: 18px; background: rgba(255, 255, 255, .08); }
.demo-card-heading h3 { margin: 0; font-size: 1.15rem; }
.demo-card-heading > span { color: #b8cfcc; font-size: .84rem; }
.schedule-list { display: grid; gap: 9px; margin: 20px 0 0; padding: 0; list-style: none; }
.schedule-list li { display: grid; grid-template-columns: 42px 100px minmax(0, 1fr) auto; align-items: center; gap: 10px; padding: 12px; border-radius: 10px; color: #c7d9d6; background: rgba(5, 30, 39, .28); font-size: .9rem; }
.schedule-list strong { color: #fff; }
.period { font-weight: 800; color: #89d5ca; }
.schedule-list--next { outline: 1px solid #83d2c7; background: rgba(15, 118, 110, .28) !important; }
.schedule-list em { padding: 3px 7px; border-radius: 999px; color: #0b4b44; background: #9ce1d6; font-size: .75rem; font-style: normal; font-weight: 800; }
.demo-card--next { display: flex; flex-direction: column; }
.demo-card--next h3 { margin: 5px 0 0; font-size: 1.35rem; }
.next-time { margin: 6px 0 18px; color: #b8cfcc; }
.next-summary { display: grid; gap: 12px; margin: 0; }
.next-summary div { display: flex; justify-content: space-between; gap: 14px; }
.next-summary dt { color: #b8cfcc; }
.next-summary dd { margin: 0; color: #fff; font-weight: 750; }
.demo-action { margin-top: auto; padding-top: 22px; color: #9ce1d6; font-weight: 750; }
.class-summary { margin-top: 18px; }
.class-snapshot-grid { display: grid; grid-template-columns: repeat(3, minmax(0, 1fr)); gap: 12px; margin-top: 18px; }
.class-snapshot { display: flex; align-items: center; justify-content: space-between; gap: 16px; padding: 15px; border-radius: 12px; background: rgba(5, 30, 39, .3); }
.class-snapshot h4 { margin: 0 0 4px; font-size: 1rem; }
.class-snapshot p { margin: 0; color: #b8cfcc; font-size: .8rem; }
.class-snapshot > strong { color: #9ce1d6; font-size: 1.7rem; }
.class-snapshot small { font-size: .78rem; }
.demo-note { margin: 16px 0 0; color: #b8cfcc; font-size: .84rem; }
.proposal-rationale { display: grid; grid-template-columns: minmax(0, .8fr) minmax(0, 1.5fr); gap: 32px; margin-top: 52px; }
.proposal-rationale h2 { font-size: 1.7rem; }
.rationale-grid { display: grid; grid-template-columns: repeat(3, minmax(0, 1fr)); gap: 16px; }
.rationale-grid article { padding: 18px; border: 1px solid var(--line); border-radius: 14px; background: var(--surface); }
.rationale-grid h3 { margin-bottom: 8px; font-size: 1.05rem; }
.rationale-grid p { margin: 0; color: var(--muted); font-size: .92rem; }
.proposal-next { display: flex; align-items: center; justify-content: space-between; gap: 28px; margin-top: 28px; padding: 28px; border: 1px solid var(--line); border-radius: 20px; background: var(--surface); box-shadow: 0 8px 22px rgba(23, 50, 77, .05); }
.proposal-next h2 { margin-bottom: 8px; font-size: 1.3rem; }
.proposal-next p:last-child { margin: 0; color: var(--muted); }

.class-workspace-demo { padding: 28px; border: 1px solid #cbdcda; border-radius: 24px; background: #f1f8f7; box-shadow: var(--shadow); }
.workspace-header, .workspace-card-heading { display: flex; align-items: start; justify-content: space-between; gap: 20px; }
.workspace-header { margin-bottom: 22px; }
.workspace-header .section-label { margin-bottom: 7px; }
.workspace-header h2 { margin: 0 0 7px; color: #12384a; font-size: 1.75rem; }
.workspace-header h2 span { color: var(--muted); font-size: 1rem; font-weight: 600; }
.workspace-header p { margin: 0; color: var(--muted); font-size: .9rem; }
.lesson-count { display: flex; align-items: center; gap: 10px; padding: 11px 15px; border-radius: 14px; color: #fff; background: var(--primary-dark); }
.lesson-count strong { font-size: 2rem; line-height: 1; }
.lesson-count span { font-size: .76rem; line-height: 1.35; }
.workspace-grid { display: grid; grid-template-columns: minmax(0, 1.4fr) minmax(270px, .75fr); gap: 18px; }
.workspace-card { padding: 22px; border: 1px solid #d3e3e0; border-radius: 18px; background: #fff; }
.workspace-card-heading h3 { margin: 0; color: #12384a; font-size: 1.15rem; }
.workspace-card-heading > span { color: var(--muted); font-size: .84rem; }
.workspace-instruction { margin: 18px 0 12px; color: var(--muted); font-size: .9rem; }
.progress-choices { display: grid; grid-template-columns: repeat(2, minmax(0, 1fr)); gap: 10px; }
.progress-choice { display: flex; flex-direction: column; align-items: start; gap: 4px; min-height: 74px; padding: 12px; border: 1px solid #c6d8d5; border-radius: 12px; color: var(--ink); background: #fbfdfd; font: inherit; text-align: left; }
.progress-choice span { font-weight: 750; }
.progress-choice strong { color: var(--muted); font-size: .78rem; }
.progress-choice.is-complete { border-color: #82c7bb; background: #e8f5f1; }
.progress-choice.is-complete strong { color: var(--primary-dark); }
.progress-choice.is-current { border: 2px solid var(--primary); background: #d9f1ec; box-shadow: 0 4px 10px rgba(15, 118, 110, .12); }
.progress-choice.is-current strong { color: var(--primary-dark); }
.progress-result { margin: 17px 0 0; color: var(--primary-dark); font-size: .9rem; font-weight: 700; }
.progress-result span { display: inline-grid; width: 19px; height: 19px; place-items: center; margin-right: 5px; border-radius: 50%; color: #fff; background: var(--primary); font-size: .75rem; }
.workspace-card--plan { color: #eaf6f4; border-color: #235766; background: #164857; }
.workspace-card--plan .section-label { color: #8eddd1; }
.workspace-card--plan h3 { color: #fff; font-size: 1.3rem; }
.plan-main { margin: 17px 0 24px; color: #eaf6f4; }
.plan-details { display: grid; gap: 10px; margin: 0; }
.plan-details div { display: flex; justify-content: space-between; gap: 12px; padding-top: 10px; border-top: 1px solid rgba(234, 246, 244, .2); }
.plan-details dt { color: #b5d2ce; font-size: .84rem; }
.plan-details dd { margin: 0; color: #fff; font-size: .87rem; font-weight: 700; text-align: right; }
.workspace-card--note, .workspace-card--history { margin-top: 18px; }
.note-example { min-height: 86px; margin-top: 18px; padding: 14px; border: 1px solid #c5d6d3; border-radius: 11px; color: #425f6f; background: #fbfdfd; font-size: .94rem; }
.record-actions { display: flex; align-items: center; gap: 18px; margin-top: 16px; }
.record-actions .primary-link { cursor: default; }
.record-actions .secondary-link { cursor: default; }
.lesson-history { display: grid; gap: 14px; margin: 18px 0 0; padding: 0; list-style: none; }
.lesson-history li { display: grid; grid-template-columns: 86px minmax(0, 1fr); gap: 14px; padding-bottom: 14px; border-bottom: 1px solid var(--line); }
.lesson-history li:last-child { padding-bottom: 0; border-bottom: 0; }
.lesson-history time { color: var(--primary-dark); font-size: .87rem; font-weight: 800; }
.lesson-history strong { color: #12384a; }
.lesson-history p { margin: 3px 0 0; color: var(--muted); font-size: .9rem; }
.workspace-rationale { margin-top: 44px; }

@media (max-width: 760px) {
    .site-header {
        align-items: flex-start;
        flex-wrap: wrap;
        padding: 18px 0;
    }

    .page-shell {
        padding-top: 34px;
    }

    .hero {
        padding: 20px 0 60px;
    }

    .info-panel,
    .link-grid {
        grid-template-columns: 1fr;
    }

    .section-heading {
        align-items: start;
        flex-direction: column;
    }

    .feature-card {
        min-height: 220px;
    }

    .auth-card { padding: 24px; }
    .query-panel { grid-template-columns: 1fr; }
    .query-field--search { grid-column: auto; }
    .query-actions { align-items: center; }
    .results-panel { padding: 18px; }
    .proposal-intro, .proposal-rationale, .proposal-next { align-items: start; grid-template-columns: 1fr; flex-direction: column; }
    .proposal-status { width: 100%; }
    .teacher-demo { padding: 18px; }
    .demo-overview-grid, .class-snapshot-grid, .rationale-grid { grid-template-columns: 1fr; }
    .workspace-grid, .progress-choices { grid-template-columns: 1fr; }
    .class-workspace-demo { padding: 18px; }
    .workspace-header { flex-direction: column; }
    .lesson-history li { grid-template-columns: 1fr; gap: 3px; }
    .schedule-list li { grid-template-columns: 38px minmax(0, 1fr) auto; }
    .schedule-list li > span:nth-child(2) { grid-column: 2; font-size: .8rem; }
    .schedule-list strong { grid-column: 2; }
}