:root {
    --paper: #f7f1e6;
    --paper-light: #fffaf1;
    --ink: #27302d;
    --muted: #626a65;
    --sun: #f2b72b;
    --sun-soft: #f9d978;
    --coral: #e96f51;
    --aqua: #55b8ae;
    --line: rgba(39, 48, 45, 0.18);
    --shadow: 0 24px 70px rgba(64, 53, 35, 0.12);
    --max-width: 1180px;
}

*,
*::before,
*::after {
    box-sizing: border-box;
}

html {
    scroll-behavior: smooth;
}

body {
    margin: 0;
    background: var(--paper);
    color: var(--ink);
    font-family: "Segoe UI", Arial, sans-serif;
    font-size: 18px;
    line-height: 1.55;
    text-rendering: optimizeLegibility;
}

a {
    color: inherit;
    text-decoration-thickness: 1px;
    text-underline-offset: 0.2em;
}

img {
    display: block;
    max-width: 100%;
    height: auto;
}

h1,
h2,
h3,
p {
    margin-top: 0;
}

h1,
h2,
h3 {
    font-family: Georgia, "Times New Roman", serif;
    font-weight: 600;
    line-height: 1.04;
    letter-spacing: -0.035em;
}

h1 {
    max-width: 800px;
    margin-bottom: 28px;
    font-size: clamp(3rem, 6vw, 6.5rem);
}

h2 {
    margin-bottom: 24px;
    font-size: clamp(2.4rem, 4.7vw, 4.8rem);
}

h3 {
    margin-bottom: 12px;
    font-size: clamp(1.45rem, 2.1vw, 2rem);
}

.container {
    width: min(calc(100% - 48px), var(--max-width));
    margin-inline: auto;
}

.skip-link {
    position: fixed;
    z-index: 100;
    top: 12px;
    left: 12px;
    padding: 10px 14px;
    transform: translateY(-160%);
    background: var(--ink);
    color: white;
}

.skip-link:focus {
    transform: translateY(0);
}

:focus-visible {
    outline: 3px solid var(--coral);
    outline-offset: 4px;
}

.site-header {
    position: relative;
    z-index: 10;
    border-bottom: 1px solid var(--line);
    background: rgba(247, 241, 230, 0.94);
}

.header-inner {
    min-height: 92px;
    display: flex;
    align-items: center;
    justify-content: space-between;
    gap: 32px;
}

.brand {
    display: inline-flex;
    align-items: center;
    gap: 12px;
    text-decoration: none;
}

.brand-mark {
    width: 44px;
    height: 44px;
    display: grid;
    place-items: center;
    border-radius: 12px 12px 12px 3px;
    background: var(--sun);
    font-family: Georgia, "Times New Roman", serif;
    font-size: 25px;
    font-weight: 700;
}

.brand-name {
    font-size: 0.93rem;
    font-weight: 800;
    letter-spacing: 0.17em;
}

.main-nav {
    display: flex;
    flex-wrap: wrap;
    justify-content: flex-end;
    gap: 12px 30px;
    font-size: 0.86rem;
    font-weight: 650;
}

.main-nav a {
    text-decoration: none;
}

.main-nav a:hover {
    text-decoration: underline;
}

.hero {
    position: relative;
    min-height: 760px;
    overflow: hidden;
    isolation: isolate;
}

.hero-grid {
    position: relative;
    min-height: 760px;
    display: grid;
    grid-template-columns: minmax(0, 1.2fr) minmax(330px, 0.8fr);
    align-items: center;
    gap: 48px;
    padding-block: 78px 92px;
}

.hero-copy {
    position: relative;
    z-index: 2;
}

.section-kicker {
    margin-bottom: 20px;
    color: var(--muted);
    font-size: 0.78rem;
    font-weight: 800;
    letter-spacing: 0.16em;
    text-transform: uppercase;
}

.hero-lead {
    max-width: 680px;
    margin-bottom: 36px;
    color: var(--muted);
    font-size: clamp(1.08rem, 1.7vw, 1.35rem);
}

.hero-actions {
    display: flex;
    flex-wrap: wrap;
    gap: 14px;
}

.button {
    min-height: 54px;
    display: inline-flex;
    align-items: center;
    justify-content: center;
    padding: 13px 22px;
    border: 2px solid var(--ink);
    border-radius: 10px 10px 10px 2px;
    font-size: 0.92rem;
    font-weight: 750;
    text-decoration: none;
    transition: transform 160ms ease, box-shadow 160ms ease, background 160ms ease;
}

.button:hover {
    transform: translateY(-2px);
}

.button-primary {
    background: var(--ink);
    color: white;
    box-shadow: 6px 6px 0 var(--sun);
}

.button-secondary {
    background: transparent;
}

.button-secondary:hover {
    background: var(--paper-light);
}

.hero-visual {
    position: relative;
    z-index: 1;
    margin: 0;
}

.hero-visual::before {
    position: absolute;
    z-index: -1;
    inset: 12% -18% 4% 3%;
    border-radius: 45% 55% 35% 65% / 45% 38% 62% 55%;
    background: var(--sun-soft);
    content: "";
    transform: rotate(-5deg);
}

.hero-visual img {
    width: min(100%, 560px);
    margin-inline: auto;
    filter: drop-shadow(0 28px 25px rgba(74, 59, 33, 0.16));
}

.visual-note {
    position: absolute;
    z-index: 2;
    padding: 8px 11px;
    border: 1px solid var(--ink);
    background: var(--paper-light);
    font-size: 0.72rem;
    font-weight: 800;
    letter-spacing: 0.13em;
    text-transform: uppercase;
    box-shadow: 4px 4px 0 var(--coral);
}

.visual-note-top {
    top: 7%;
    left: -2%;
    transform: rotate(-6deg);
}

.visual-note-bottom {
    right: -2%;
    bottom: 10%;
    transform: rotate(5deg);
}

.hero-shape {
    position: absolute;
    z-index: -1;
    border-radius: 50%;
    opacity: 0.9;
}

.hero-shape-one {
    width: 240px;
    height: 240px;
    top: 58px;
    right: -70px;
    border: 50px solid var(--aqua);
}

.hero-shape-two {
    width: 180px;
    height: 90px;
    bottom: -18px;
    left: 10%;
    border-radius: 100% 100% 0 0;
    background: var(--coral);
}

.section {
    padding-block: 112px;
}

.principles {
    border-block: 1px solid var(--line);
    background: var(--paper-light);
}

.heading-split {
    display: grid;
    grid-template-columns: minmax(0, 1.4fr) minmax(260px, 0.6fr);
    align-items: end;
    gap: 56px;
    margin-bottom: 70px;
}

.heading-split h2,
.heading-split p {
    margin-bottom: 0;
}

.heading-split p {
    color: var(--muted);
}

.principle-list {
    display: grid;
    grid-template-columns: repeat(3, 1fr);
    gap: 0;
    margin: 0;
    padding: 0;
    list-style: none;
}

.principle-item {
    min-height: 280px;
    display: flex;
    flex-direction: column;
    justify-content: space-between;
    gap: 48px;
    padding: 30px 34px 34px;
    border-top: 3px solid var(--ink);
}

.principle-item + .principle-item {
    border-left: 1px solid var(--line);
}

.principle-item:nth-child(1) {
    background: rgba(242, 183, 43, 0.12);
}

.principle-item:nth-child(2) {
    background: rgba(85, 184, 174, 0.10);
}

.principle-item:nth-child(3) {
    background: rgba(233, 111, 81, 0.10);
}

.principle-number {
    color: var(--coral);
    font-family: Georgia, "Times New Roman", serif;
    font-size: 1.05rem;
    font-weight: 700;
}

.principle-item p {
    margin-bottom: 0;
    color: var(--muted);
    font-size: 0.96rem;
}

.status-section {
    position: relative;
    background: var(--sun);
}

.status-layout {
    display: grid;
    grid-template-columns: minmax(0, 0.78fr) minmax(0, 1.22fr);
    gap: 88px;
}

.status-intro > p:not(.section-kicker) {
    max-width: 480px;
}

.status-intro img {
    width: min(100%, 430px);
    margin-top: 26px;
    margin-left: -32px;
}

.status-list {
    align-self: center;
    border-top: 2px solid var(--ink);
}

.status-row {
    display: grid;
    grid-template-columns: 46px 1fr;
    gap: 22px;
    padding-block: 30px 32px;
    border-bottom: 2px solid var(--ink);
}

.status-index {
    width: 34px;
    height: 34px;
    display: grid;
    place-items: center;
    border: 1px solid var(--ink);
    border-radius: 50%;
    font-size: 0.8rem;
    font-weight: 800;
}

.status-row h3 {
    margin-bottom: 8px;
}

.status-row p {
    max-width: 580px;
    margin-bottom: 0;
}

.status-row a {
    display: inline-block;
    margin-top: 15px;
    font-weight: 800;
}

.organization {
    background: var(--ink);
    color: var(--paper-light);
}

.organization .section-kicker {
    color: var(--sun-soft);
}

.organization-grid {
    display: grid;
    grid-template-columns: minmax(0, 0.85fr) minmax(0, 1.15fr);
    gap: 90px;
}

.organization-copy > p:not(.section-kicker) {
    max-width: 540px;
    color: #d5d8d4;
}

.source-link {
    display: inline-block;
    margin-top: 18px;
    color: var(--sun-soft);
    font-weight: 750;
}

.facts {
    display: grid;
    grid-template-columns: repeat(2, minmax(0, 1fr));
    align-content: start;
    gap: 0;
    margin: 0;
    border-top: 1px solid rgba(255, 255, 255, 0.25);
}

.facts > div {
    padding: 25px 24px 28px 0;
    border-bottom: 1px solid rgba(255, 255, 255, 0.25);
}

.facts > div:nth-child(2n) {
    padding-left: 24px;
    border-left: 1px solid rgba(255, 255, 255, 0.25);
}

.facts .facts-wide {
    grid-column: 1 / -1;
    padding-left: 0;
    border-left: 0;
}

.facts dt {
    margin-bottom: 8px;
    color: #aeb5b0;
    font-size: 0.75rem;
    font-weight: 750;
    letter-spacing: 0.12em;
    text-transform: uppercase;
}

.facts dd {
    margin: 0;
    overflow-wrap: anywhere;
    font-size: 1.05rem;
}

.contact-band {
    background: var(--coral);
}

.contact-inner {
    min-height: 290px;
    display: flex;
    align-items: center;
    justify-content: space-between;
    gap: 50px;
    padding-block: 64px;
}

.contact-inner h2 {
    max-width: 650px;
    margin-bottom: 0;
}

.contact-email {
    flex: 0 0 auto;
    padding: 16px 0;
    border-bottom: 3px solid var(--ink);
    font-size: clamp(1rem, 2vw, 1.35rem);
    font-weight: 800;
    text-decoration: none;
}

.site-footer {
    background: var(--paper-light);
}

.footer-inner {
    min-height: 150px;
    display: grid;
    grid-template-columns: 0.7fr 1.3fr;
    align-items: center;
    gap: 44px;
    padding-block: 34px;
    color: var(--muted);
    font-size: 0.82rem;
}

.footer-inner p {
    margin-bottom: 0;
}

.error-page {
    min-height: 100vh;
    display: grid;
    place-items: center;
    padding: 24px;
    background: linear-gradient(135deg, var(--paper), var(--sun-soft));
}

.error-card {
    width: min(100%, 660px);
    padding: clamp(34px, 7vw, 72px);
    border: 2px solid var(--ink);
    background: var(--paper-light);
    box-shadow: 12px 12px 0 var(--coral);
}

.error-card .brand {
    margin-bottom: 55px;
}

.error-code {
    color: var(--coral);
    font-weight: 800;
}

.error-card h1 {
    font-size: clamp(2.5rem, 7vw, 4.5rem);
}

.error-card .button {
    margin-top: 18px;
}

@media (max-width: 900px) {
    .hero-grid,
    .status-layout,
    .organization-grid {
        grid-template-columns: 1fr;
    }

    .hero-grid {
        gap: 26px;
        padding-top: 66px;
    }

    .hero-visual {
        width: min(78vw, 560px);
        margin-inline: auto;
    }

    .heading-split {
        grid-template-columns: 1fr;
        gap: 18px;
    }

    .principle-list {
        grid-template-columns: 1fr;
    }

    .principle-item {
        min-height: 0;
    }

    .principle-item + .principle-item {
        border-left: 0;
    }

    .status-layout {
        gap: 50px;
    }

    .status-intro img {
        width: min(64vw, 420px);
        margin-inline: auto;
    }

    .organization-grid {
        gap: 52px;
    }

    .contact-inner {
        align-items: flex-start;
        flex-direction: column;
        justify-content: center;
        gap: 24px;
    }
}

@media (max-width: 680px) {
    body {
        font-size: 16px;
    }

    .container {
        width: min(calc(100% - 32px), var(--max-width));
    }

    .header-inner {
        min-height: 118px;
        align-items: flex-start;
        flex-direction: column;
        justify-content: center;
        gap: 14px;
        padding-block: 16px;
    }

    .main-nav {
        justify-content: flex-start;
        gap: 8px 18px;
        font-size: 0.78rem;
    }

    .hero,
    .hero-grid {
        min-height: 0;
    }

    .hero-grid {
        padding-block: 58px 70px;
    }

    .hero-actions {
        align-items: stretch;
        flex-direction: column;
    }

    .button {
        width: 100%;
    }

    .hero-visual {
        width: min(86vw, 460px);
    }

    .visual-note-bottom {
        right: 0;
    }

    .section {
        padding-block: 78px;
    }

    .heading-split {
        margin-bottom: 46px;
    }

    .principle-item {
        gap: 30px;
        padding-inline: 20px;
    }

    .status-row {
        grid-template-columns: 38px 1fr;
        gap: 14px;
    }

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

    .facts > div,
    .facts > div:nth-child(2n) {
        padding-inline: 0;
        border-left: 0;
    }

    .facts .facts-wide {
        grid-column: auto;
    }

    .contact-inner {
        min-height: 260px;
    }

    .contact-email {
        max-width: 100%;
        overflow-wrap: anywhere;
    }

    .footer-inner {
        grid-template-columns: 1fr;
        gap: 14px;
    }
}

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

    *,
    *::before,
    *::after {
        scroll-behavior: auto !important;
        transition-duration: 0.01ms !important;
    }
}

@media print {
    .site-header,
    .hero-actions,
    .contact-band,
    .site-footer,
    .hero-shape,
    .visual-note {
        display: none;
    }

    body,
    .principles,
    .organization,
    .status-section {
        background: white;
        color: black;
    }

    .section,
    .hero-grid {
        min-height: 0;
        padding-block: 32px;
    }
}

.main-nav a[aria-current="page"] {
    text-decoration: underline;
    text-decoration-thickness: 2px;
    text-decoration-color: var(--coral);
}

.page-intro {
    position: relative;
    padding-block: 72px 56px;
    border-bottom: 1px solid var(--line);
    background: var(--paper-light);
}

.page-intro h1 {
    font-size: clamp(2.4rem, 5vw, 4.6rem);
    margin-bottom: 22px;
}

.page-intro-grid {
    display: grid;
    grid-template-columns: minmax(0, 1.35fr) minmax(280px, 0.65fr);
    align-items: start;
    gap: 56px;
}

.breadcrumbs {
    margin-bottom: 18px;
    color: var(--muted);
    font-size: 0.86rem;
    font-weight: 650;
}

.breadcrumbs a {
    text-decoration: none;
}

.breadcrumbs a:hover {
    text-decoration: underline;
}

.notice {
    padding: 24px 26px 26px;
    border: 2px solid var(--ink);
    background: var(--paper);
    box-shadow: 8px 8px 0 var(--sun);
    font-size: 0.92rem;
}

.notice ul {
    margin: 0;
    padding-left: 20px;
}

.notice li + li {
    margin-top: 10px;
}

.notice-title {
    margin-bottom: 12px;
    color: var(--coral);
    font-size: 0.78rem;
    font-weight: 800;
    letter-spacing: 0.14em;
    text-transform: uppercase;
}

.lessons-section {
    border-block: 1px solid var(--line);
    background: var(--paper);
}

.lessons-index {
    background: var(--paper);
}

.lessons-howto {
    border-top: 1px solid var(--line);
    background: var(--paper-light);
}

.lesson-list {
    margin: 0 0 44px;
    padding: 0;
    border-top: 2px solid var(--ink);
    list-style: none;
}

.lesson-item {
    display: grid;
    grid-template-columns: 64px minmax(0, 1fr);
    gap: 26px;
    padding-block: 28px 30px;
    border-bottom: 1px solid var(--line);
}

.lesson-item h3 {
    margin-bottom: 10px;
}

.lesson-item h3 a {
    text-decoration: none;
}

.lesson-item h3 a:hover,
.lesson-item h3 a:focus-visible {
    text-decoration: underline;
    text-decoration-color: var(--coral);
}

.lesson-item p {
    max-width: 720px;
    margin-bottom: 0;
    color: var(--muted);
    font-size: 0.98rem;
}

.lesson-number {
    padding-top: 6px;
    color: var(--coral);
    font-family: Georgia, "Times New Roman", serif;
    font-size: 1.5rem;
    font-weight: 700;
}

.lesson-meta {
    display: flex;
    flex-wrap: wrap;
    gap: 8px;
    margin-top: 12px;
    font-size: 0.8rem;
    font-weight: 750;
    letter-spacing: 0.08em;
    text-transform: uppercase;
}

.lesson-header .section-kicker {
    display: flex;
    flex-wrap: wrap;
    gap: 10px;
}

.lesson-layout {
    display: grid;
    grid-template-columns: minmax(0, 1fr) minmax(240px, 300px);
    align-items: start;
    gap: 64px;
    padding-block: 64px 40px;
}

.lesson-body {
    min-width: 0;
    max-width: 760px;
    font-size: 1.05rem;
}

.lesson-body h2 {
    margin-top: 56px;
    margin-bottom: 18px;
    font-size: clamp(1.7rem, 3vw, 2.5rem);
}

.lesson-body > section > h2:first-child {
    margin-top: 0;
}

.lesson-body h3 {
    margin-top: 34px;
    font-size: clamp(1.25rem, 2vw, 1.6rem);
}

.lesson-body p,
.lesson-body ul,
.lesson-body ol {
    margin-bottom: 20px;
}

.lesson-body ul,
.lesson-body ol {
    padding-left: 26px;
}

.lesson-body li + li {
    margin-top: 8px;
}

.lesson-body code,
.lesson-body pre,
.lesson-body kbd {
    font-family: "Cascadia Mono", Consolas, "Liberation Mono", Menlo, monospace;
    font-size: 0.92em;
}

.lesson-body code {
    padding: 0.1em 0.35em;
    border-radius: 5px;
    background: rgba(39, 48, 45, 0.08);
}

.lesson-body pre {
    margin: 0 0 24px;
    padding: 20px 22px;
    overflow-x: auto;
    border: 1px solid var(--line);
    border-left: 5px solid var(--sun);
    border-radius: 8px 8px 8px 2px;
    background: var(--ink);
    color: #f3efe6;
    line-height: 1.5;
    tab-size: 4;
}

.lesson-body pre code {
    padding: 0;
    background: none;
}

.lesson-body table {
    width: 100%;
    margin-bottom: 24px;
    border-collapse: collapse;
    font-size: 0.95rem;
}

.lesson-body th,
.lesson-body td {
    padding: 10px 12px;
    border-bottom: 1px solid var(--line);
    text-align: left;
    vertical-align: top;
}

.lesson-body th {
    font-size: 0.78rem;
    font-weight: 800;
    letter-spacing: 0.1em;
    text-transform: uppercase;
}

.lesson-body .table-scroll {
    margin-bottom: 24px;
    overflow-x: auto;
}

.lesson-body .callout {
    margin: 0 0 24px;
    padding: 20px 24px;
    border: 1px solid var(--ink);
    border-left: 6px solid var(--coral);
    background: var(--paper-light);
}

.lesson-body .callout p:last-child,
.lesson-body .callout ul:last-child,
.lesson-body .callout ol:last-child {
    margin-bottom: 0;
}

.lesson-body .callout-title {
    margin-bottom: 8px;
    font-size: 0.78rem;
    font-weight: 800;
    letter-spacing: 0.14em;
    text-transform: uppercase;
}

.lesson-body .exercise {
    margin: 40px 0 0;
    padding: 26px 28px 28px;
    border: 2px solid var(--ink);
    background: var(--sun-soft);
    box-shadow: 8px 8px 0 var(--aqua);
}

.lesson-body .exercise h2 {
    margin-top: 0;
    font-size: clamp(1.4rem, 2.4vw, 1.9rem);
}

.lesson-body .exercise p:last-child,
.lesson-body .exercise ol:last-child {
    margin-bottom: 0;
}

.lesson-aside {
    position: sticky;
    top: 24px;
    padding: 22px 24px;
    border: 1px solid var(--line);
    background: var(--paper-light);
    color: var(--muted);
    font-size: 0.88rem;
}

.lesson-aside p:last-child {
    margin-bottom: 0;
}

.lesson-nav {
    display: grid;
    grid-template-columns: repeat(3, minmax(0, 1fr));
    gap: 16px;
    padding-block: 24px 80px;
}

.lesson-nav-link {
    display: flex;
    flex-direction: column;
    gap: 8px;
    padding: 18px 20px;
    border: 2px solid var(--ink);
    border-radius: 10px 10px 10px 2px;
    background: var(--paper-light);
    font-weight: 700;
    text-decoration: none;
    transition: transform 160ms ease, box-shadow 160ms ease;
}

.lesson-nav-link:hover {
    transform: translateY(-2px);
    box-shadow: 6px 6px 0 var(--sun);
}

.lesson-nav-previous {
    grid-column: 1;
}

.lesson-nav-index {
    grid-column: 2;
    text-align: center;
}

.lesson-nav-next {
    grid-column: 3;
    text-align: right;
}

.lesson-nav-label {
    color: var(--muted);
    font-size: 0.74rem;
    font-weight: 800;
    letter-spacing: 0.12em;
    text-transform: uppercase;
}

@media (max-width: 900px) {
    .page-intro-grid,
    .lesson-layout {
        grid-template-columns: minmax(0, 1fr);
        gap: 32px;
    }

    .lesson-aside {
        position: static;
    }

    .lesson-nav {
        grid-template-columns: minmax(0, 1fr);
    }

    .lesson-nav-previous,
    .lesson-nav-index,
    .lesson-nav-next {
        grid-column: auto;
        text-align: left;
    }
}

@media (max-width: 680px) {
    .page-intro {
        padding-block: 48px 40px;
    }

    .lesson-item {
        grid-template-columns: 44px minmax(0, 1fr);
        gap: 14px;
    }

    .lesson-number {
        font-size: 1.2rem;
    }

    .lesson-body pre {
        padding: 16px;
    }

    .lesson-body .exercise {
        padding: 20px;
    }
}

@media print {
    .lesson-aside,
    .lesson-nav,
    .breadcrumbs {
        display: none;
    }

    .lesson-body pre {
        border: 1px solid black;
        background: white;
        color: black;
    }
}