:root {
    --paper: #f6f1e6;
    --paper-deep: #efe6d6;
    --ink: #1d1914;
    --ink-soft: #4a433a;
    --line: rgba(29, 25, 20, 0.14);
    --student: #7a3324;
    --student-wash: rgba(122, 51, 36, 0.06);
    --teacher: #1c3b4e;
    --teacher-wash: rgba(28, 59, 78, 0.045);
    --summary: #e5eee4;
    --summary-ink: #24362c;
    --seal: #9b2c2c;
    --shadow: 0 18px 50px rgba(70, 48, 20, 0.08);
    --serif: "Literata", "Palatino Linotype", Palatino, "Times New Roman", serif;
    --cjk: "Noto Serif SC", "Songti SC", SimSun, "Noto Serif CJK SC", serif;
}

* {
    box-sizing: border-box;
}

html {
    scroll-behavior: smooth;
}

body {
    margin: 0;
    color: var(--ink);
    font-family: var(--serif);
    font-size: 1.125rem;
    line-height: 1.7;
    background:
        radial-gradient(ellipse at top, rgba(255, 252, 245, 0.9), transparent 52%),
        linear-gradient(180deg, #f3ecdf 0%, var(--paper) 28%, #e9e0d0 100%);
}

body::before {
    content: "";
    position: fixed;
    inset: 0;
    pointer-events: none;
    opacity: 0.18;
    background-image: radial-gradient(rgba(70, 50, 20, 0.35) 0.4px, transparent 0.4px);
    background-size: 3px 3px;
}

a {
    color: var(--teacher);
}

a:hover {
    color: var(--seal);
}

.skip {
    position: absolute;
    left: 1rem;
    top: -4rem;
    background: var(--ink);
    color: var(--paper);
    padding: 0.5rem 0.8rem;
    z-index: 5;
}

.skip:focus {
    top: 1rem;
}

.page {
    width: min(1120px, calc(100% - 2rem));
    margin: 0 auto;
    padding: 2.2rem 0 4rem;
    display: grid;
    grid-template-columns: 240px minmax(0, 1fr);
    gap: 2rem;
    position: relative;
}

.masthead,
.lede,
.toolbar,
.pager,
.lesson,
.closing-note,
.toc {
    min-width: 0;
}

.masthead,
.toolbar,
.pager,
.lesson,
.closing-note {
    grid-column: 2;
}

.toc {
    grid-column: 1;
    grid-row: 1 / span 8;
    align-self: start;
    position: sticky;
    top: 1.2rem;
    padding: 1rem 0.2rem 1rem 0;
}

.toc__label {
    margin: 0 0 0.7rem;
    font-size: 0.75rem;
    letter-spacing: 0.16em;
    text-transform: uppercase;
    color: var(--ink-soft);
}

.toc ol {
    list-style: none;
    margin: 0;
    padding: 0;
    border-left: 1px solid var(--line);
}

.toc a {
    display: block;
    padding: 0.38rem 0 0.38rem 0.85rem;
    color: var(--ink-soft);
    text-decoration: none;
    font-size: 0.95rem;
    line-height: 1.35;
}

.toc a:hover,
.toc a.is-current {
    color: var(--ink);
    box-shadow: inset 2px 0 0 var(--seal);
}

.masthead {
    display: flex;
    gap: 1.4rem;
    align-items: center;
    padding-bottom: 1.4rem;
    border-bottom: 1px solid var(--line);
}

.seal {
    flex: 0 0 auto;
    width: 4.6rem;
    height: 4.6rem;
    display: grid;
    place-items: center;
    border: 2px solid var(--seal);
    color: var(--seal);
    font-family: var(--cjk);
    font-size: 2rem;
    transform: rotate(-8deg);
    background: rgba(155, 44, 44, 0.04);
    box-shadow: inset 0 0 0 3px rgba(155, 44, 44, 0.25);
}

.kicker {
    margin: 0 0 0.2rem;
    letter-spacing: 0.18em;
    text-transform: uppercase;
    font-size: 0.75rem;
    color: var(--seal);
}

h1 {
    margin: 0;
    font-weight: 560;
    font-size: clamp(2rem, 4vw, 3.1rem);
    line-height: 1.15;
    letter-spacing: -0.02em;
}

.masthead__en {
    margin: 0.35rem 0 0;
    color: var(--ink-soft);
}

.lede {
    grid-column: 2;
    margin: 1.3rem 0 0;
    max-width: 42rem;
    color: var(--ink-soft);
}

.lede a {
    text-underline-offset: 0.18em;
}

.toolbar {
    display: flex;
    flex-wrap: wrap;
    gap: 0.8rem 1.2rem;
    align-items: center;
    margin-top: 1.2rem;
}

.pager {
    display: flex;
    flex-direction: column;
    align-items: flex-start;
    gap: 0.55rem;
    margin-top: 1.15rem;
}

.pager__chapters {
    display: flex;
    flex-wrap: wrap;
    gap: 0.45rem;
}

.pager a {
    text-decoration: none;
    border: 1px solid rgba(29, 25, 20, 0.35);
    color: var(--ink);
    font-size: 0.98rem;
}

.pager__home {
    border-radius: 999px;
    padding: 0.28rem 0.85rem;
}

.pager__chapters a {
    width: 2.45rem;
    height: 2.45rem;
    padding: 0;
    border-radius: 50%;
    display: grid;
    place-items: center;
    line-height: 1;
}

.pager a:hover,
.pager a[aria-current="page"] {
    border-color: var(--seal);
    color: var(--seal);
}

.progress {
    margin: 0;
    color: var(--ink-soft);
    font-size: 0.98rem;
}

.btn {
    font: inherit;
    font-size: 1rem;
    color: var(--ink);
    background: transparent;
    border: 1px solid rgba(29, 25, 20, 0.35);
    border-radius: 999px;
    padding: 0.45rem 1rem;
    cursor: pointer;
}

.btn:hover {
    border-color: var(--seal);
    color: var(--seal);
}

.btn:disabled {
    cursor: default;
    opacity: 0.55;
}

.lesson {
    margin-top: 1.6rem;
    padding: 1.5rem 1.5rem 1.25rem;
    background: rgba(255, 251, 245, 0.78);
    border: 1px solid rgba(255, 252, 247, 0.9);
    box-shadow: var(--shadow);
    scroll-margin-top: 1rem;
}

.lesson.is-active {
    box-shadow: var(--shadow), inset 3px 0 0 var(--seal);
}

.lesson__index {
    margin: 0;
    font-size: 0.78rem;
    letter-spacing: 0.14em;
    text-transform: uppercase;
    color: var(--seal);
}

.lesson.is-complete .lesson__index::after {
    content: " · обобщението е прочетено";
    letter-spacing: 0.04em;
    text-transform: none;
    color: var(--summary-ink);
}

.lesson h2 {
    margin: 0.25rem 0 1rem;
    font-size: 1.7rem;
    font-weight: 560;
    letter-spacing: -0.02em;
    line-height: 1.25;
}

.verse {
    margin: 0 0 0.4rem;
    padding: 1rem 1.1rem 0.9rem;
    background: var(--paper-deep);
    border-left: 3px solid var(--seal);
}

.verse__zh {
    margin: 0;
    font-family: var(--cjk);
    font-size: 1.85rem;
    line-height: 1.85;
    letter-spacing: 0.04em;
}

.gloss {
    font-family: var(--serif);
    font-size: 0.38em;
    letter-spacing: 0;
    line-height: 1;
    text-transform: none;
    color: var(--ink-soft);
    white-space: nowrap;
    margin-left: 0.12em;
    margin-right: 0.28em;
    vertical-align: 0.45em;
}

.kicker .gloss,
.catalog__index .gloss {
    font-size: 1em;
    margin: 0;
    vertical-align: baseline;
    color: inherit;
}

.zi {
    white-space: nowrap;
}

.verse__py,
.verse__bg {
    margin: 0.35rem 0 0;
}

.verse__py {
    font-style: italic;
    color: var(--ink-soft);
}

.verse__bg {
    font-size: 1.2rem;
}

.dialogue {
    margin-top: 0.4rem;
}

.turn {
    display: grid;
    grid-template-columns: 8.2rem minmax(0, 1fr);
    gap: 0.8rem 1rem;
    padding: 0.95rem 0.8rem;
    margin-top: 0.55rem;
}

.turn--student {
    background: var(--student-wash);
}

.turn--teacher {
    background: var(--teacher-wash);
}

.turn__who {
    margin: 0.2rem 0 0;
    font-size: 0.78rem;
    letter-spacing: 0.12em;
    text-transform: uppercase;
}

.turn--student .turn__who {
    color: var(--student);
}

.turn--teacher .turn__who {
    color: var(--teacher);
}

.turn__say p {
    margin: 0;
}

.turn__say p + p {
    margin-top: 0.75rem;
}

.summary {
    margin: 1rem 0 0.4rem;
    padding: 1rem 1.1rem 1.05rem;
    background: var(--summary);
    color: var(--summary-ink);
    border: 1px solid rgba(36, 54, 44, 0.12);
    box-shadow: inset 0 0 0 3px rgba(255, 252, 247, 0.45);
}

.summary h3 {
    margin: 0 0 0.4rem;
    font-size: 0.78rem;
    font-weight: 650;
    letter-spacing: 0.16em;
    text-transform: uppercase;
}

.summary p {
    margin: 0;
}

.summary p + p {
    margin-top: 0.7rem;
}

.lesson__controls {
    display: none;
    margin-top: 1rem;
}

.js .turn:not(.is-in),
.js .summary:not(.is-in) {
    display: none;
}

.js .lesson__controls {
    display: flex;
    flex-wrap: wrap;
    gap: 0.6rem;
}

.js .is-in {
    animation: rise 0.4s ease;
}

.closing-note {
    margin-top: 1.8rem;
    color: var(--ink-soft);
    font-size: 1rem;
}

.closing-note p {
    margin: 0.3rem 0;
}

@keyframes rise {
    from {
        opacity: 0;
        transform: translateY(8px);
    }
    to {
        opacity: 1;
        transform: none;
    }
}

:focus-visible {
    outline: 2px solid var(--seal);
    outline-offset: 3px;
}

@media (max-width: 860px) {
    .page {
        grid-template-columns: 1fr;
        width: min(760px, calc(100% - 1.4rem));
    }

    .masthead,
    .lede,
    .toolbar,
    .pager,
    .lesson,
    .closing-note,
    .toc {
        grid-column: 1;
    }

    .toc {
        position: static;
        grid-row: auto;
        padding-top: 1.2rem;
    }

    .toc ol {
        display: flex;
        gap: 0.2rem;
        max-width: 100%;
        overflow-x: auto;
        border-left: 0;
        padding-bottom: 0.4rem;
    }

    .toc a {
        white-space: nowrap;
        border: 1px solid var(--line);
        padding: 0.3rem 0.6rem;
    }

    .toc a:hover,
    .toc a.is-current {
        box-shadow: none;
        border-color: var(--seal);
    }

    .turn {
        grid-template-columns: 1fr;
        gap: 0.2rem;
    }
}

@media (prefers-reduced-motion: reduce) {
    html {
        scroll-behavior: auto;
    }

    .js .is-in {
        animation: none;
    }
}

@media print {
    body {
        background: white;
    }

    body::before,
    .toolbar,
    .lesson__controls,
    .toc,
    .skip {
        display: none !important;
    }

    .page {
        display: block;
        width: auto;
    }

    .lesson {
        box-shadow: none;
        break-inside: avoid;
    }

    .js .turn,
    .js .summary {
        display: block !important;
    }

    .turn {
        display: block !important;
    }
}

.page--index {
    grid-template-columns: minmax(0, 42rem);
    justify-content: center;
}

.page--index .masthead,
.page--index .lede,
.page--index .catalog,
.page--index .closing-note {
    grid-column: 1;
}

.catalog {
    margin-top: 1.5rem;
}

.catalog ol {
    list-style: none;
    margin: 0;
    padding: 0;
}

.catalog li + li {
    margin-top: 0.9rem;
}

.catalog__item {
    display: block;
    padding: 1.15rem 1.25rem 1.2rem;
    background: rgba(255, 251, 245, 0.78);
    border: 1px solid rgba(255, 252, 247, 0.9);
    box-shadow: var(--shadow);
    text-decoration: none;
    color: inherit;
}

.catalog__item:hover {
    box-shadow: var(--shadow), inset 3px 0 0 var(--seal);
}

.catalog__index {
    margin: 0;
    font-size: 0.78rem;
    letter-spacing: 0.14em;
    text-transform: uppercase;
    color: var(--seal);
}

.catalog__item h2 {
    margin: 0.2rem 0 0.45rem;
    font-size: 1.55rem;
    font-weight: 560;
    letter-spacing: -0.02em;
    line-height: 1.25;
    color: var(--ink);
}

.catalog__item p {
    margin: 0;
    color: var(--ink-soft);
}

.page--index {
    grid-template-columns: minmax(0, 42rem);
    justify-content: center;
}

.page--index .masthead,
.page--index .lede,
.page--index .catalog,
.page--index .closing-note {
    grid-column: 1;
}

.catalog {
    margin-top: 1.5rem;
}

.catalog ol {
    list-style: none;
    margin: 0;
    padding: 0;
}

.catalog li + li {
    margin-top: 0.9rem;
}

.catalog__item {
    display: block;
    padding: 1.15rem 1.25rem 1.2rem;
    background: rgba(255, 251, 245, 0.78);
    border: 1px solid rgba(255, 252, 247, 0.9);
    box-shadow: var(--shadow);
    text-decoration: none;
    color: inherit;
}

.catalog__item:hover {
    box-shadow: var(--shadow), inset 3px 0 0 var(--seal);
}

.catalog__index {
    margin: 0;
    font-size: 0.78rem;
    letter-spacing: 0.14em;
    text-transform: uppercase;
    color: var(--seal);
}

.catalog__item h2 {
    margin: 0.2rem 0 0.45rem;
    font-size: 1.55rem;
    font-weight: 560;
    letter-spacing: -0.02em;
    line-height: 1.25;
    color: var(--ink);
}

.catalog__item p {
    margin: 0;
    color: var(--ink-soft);
}