:root {
    color-scheme: light;
    --ink: #171923;
    --muted: #697080;
    --line: #e7e9ef;
    --blue: #2563eb;
    --purple: #7c3aed;
    --paper: #ffffff;
    --soft: #f6f7fb;
    font-family: Montserrat, Inter, ui-sans-serif, system-ui, -apple-system, BlinkMacSystemFont, "Segoe UI", sans-serif;
}

* { box-sizing: border-box; }

html { scroll-behavior: smooth; }

body {
    margin: 0;
    background: var(--paper);
    color: var(--ink);
    font-size: 16px;
    line-height: 1.75;
    -webkit-font-smoothing: antialiased;
}

a { color: inherit; }

.site-header {
    width: min(1180px, calc(100% - 48px));
    height: 82px;
    margin: 0 auto;
    display: flex;
    align-items: center;
    justify-content: space-between;
    border-bottom: 1px solid var(--line);
}

.brand img { display: block; width: 86px; height: auto; }

.site-header nav {
    display: flex;
    align-items: center;
    gap: 12px;
    color: var(--muted);
    font-size: 13px;
}

.site-header nav { min-width: 0; max-width: 70%; }
.site-header nav [aria-current="page"] { display: block; min-width: 0; max-width: min(35vw, 420px); overflow: hidden; text-overflow: ellipsis; white-space: nowrap; }
.site-header nav a { color: var(--ink); text-decoration: none; }
.site-header nav a:hover, .text-link:hover { color: var(--purple); }

.article { width: min(1180px, calc(100% - 48px)); margin: 0 auto; }

.article-header {
    max-width: 860px;
    margin: 0 auto;
    padding: 82px 0 42px;
    text-align: center;
}

.eyebrow {
    margin: 0 0 22px;
    color: var(--blue);
    font-size: 11px;
    font-weight: 700;
    letter-spacing: .14em;
}

.eyebrow span { padding: 0 7px; color: #a0a5b2; }

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

h1 {
    max-width: 850px;
    margin: 0 auto 22px;
    font-size: clamp(38px, 5.4vw, 66px);
    line-height: 1.09;
    letter-spacing: -.055em;
    font-weight: 700;
}

.intro {
    max-width: 700px;
    margin: 0 auto;
    color: var(--muted);
    font-size: clamp(17px, 2vw, 20px);
    line-height: 1.7;
}

.image-frame { margin: 0; }

.article-image {
    display: block;
    width: 100%;
    height: clamp(270px, 43vw, 510px);
    border: 1px solid #e7e9ef;
    border-radius: 22px;
    background: #fff;
    object-fit: cover;
    object-position: center;
}

.hero-frame { margin-bottom: 88px; }

.image-placeholder {
    min-height: 250px;
    display: flex;
    flex-direction: column;
    align-items: center;
    justify-content: center;
    gap: 10px;
    overflow: hidden;
    border: 1px solid #dfe5f5;
    border-radius: 22px;
    background:
        radial-gradient(ellipse at 50% 0%, rgba(124, 58, 237, .13), transparent 54%),
        linear-gradient(145deg, #f5f7ff, #f4f2fb 55%, #f8faff);
    color: #4e5c82;
    text-align: center;
}

.hero-frame .image-placeholder { min-height: clamp(270px, 43vw, 510px); }

.placeholder-mark {
    width: 48px;
    height: 48px;
    display: grid;
    place-items: center;
    margin-bottom: 6px;
    border-radius: 15px;
    background: linear-gradient(135deg, var(--blue), var(--purple));
    color: white;
    font-size: 24px;
    font-weight: 700;
    box-shadow: 0 10px 28px rgba(71, 76, 180, .2);
}

.placeholder-label { font-size: 11px; font-weight: 700; letter-spacing: .12em; }
.placeholder-note { color: #828ba1; font-size: 13px; }

figcaption {
    margin-top: 12px;
    color: #858b98;
    font-size: 12px;
    text-align: center;
}

.article-layout {
    display: grid;
    grid-template-columns: minmax(0, 700px) 230px;
    justify-content: center;
    gap: clamp(42px, 8vw, 110px);
    align-items: start;
    padding-bottom: 110px;
}

.contents {
    position: sticky;
    top: 28px;
    display: flex;
    flex-direction: column;
    padding: 18px 0;
    border-top: 1px solid var(--line);
    grid-column: 2;
    grid-row: 1;
}

.contents p {
    margin-bottom: 12px;
    color: #8a90a0;
    font-size: 10px;
    font-weight: 700;
    letter-spacing: .13em;
}

.contents a {
    padding: 7px 0;
    color: #606879;
    font-size: 12px;
    line-height: 1.5;
    text-decoration: none;
}

.contents a:hover { color: var(--blue); }

.sidebar-posts {
    display: flex;
    flex-direction: column;
    margin-top: 25px;
    padding-top: 18px;
    border-top: 1px solid var(--line);
}

.sidebar-posts p {
    margin-bottom: 10px;
    color: #8a90a0;
    font-size: 10px;
    font-weight: 700;
    letter-spacing: .13em;
}

.sidebar-posts a {
    padding: 6px 0;
    color: #606879;
    font-size: 11px;
    line-height: 1.45;
    text-decoration: none;
}

.sidebar-posts a:hover { color: var(--blue); }

.sidebar-posts .more-guides {
    margin-top: 10px;
    padding: 10px 12px;
    border: 1px solid #e2e5f0;
    border-radius: 10px;
    color: var(--blue);
    font-weight: 700;
    text-align: center;
}

.sidebar-posts .more-guides span { margin-left: 4px; }

.article-body { min-width: 0; }
.article-body { grid-column: 1; grid-row: 1; }

.article-body p, .article-body li { color: #555d6c; }
.article-body p { margin-bottom: 18px; }
.article-body .lead { color: #343a48; font-size: 19px; line-height: 1.8; }

.article-body section { margin: 56px 0; scroll-margin-top: 30px; }

.article-body h2 {
    margin-bottom: 16px;
    font-size: clamp(25px, 3vw, 34px);
    line-height: 1.25;
    letter-spacing: -.035em;
}

.article-body ul { margin: 0 0 24px; padding-left: 22px; }
.article-body li { padding-left: 5px; margin: 8px 0; }
.article-body strong { color: #292e3a; }

.article-body .image-frame { margin: 44px 0 50px; }
.article-body .image-placeholder { min-height: 300px; }
.article-body .image-placeholder--spatial { min-height: 340px; }

.note-card {
    display: grid;
    gap: 4px;
    margin: 28px 0;
    padding: 22px 24px;
    border: 1px solid #e1e6fb;
    border-radius: 14px;
    background: #f7f8ff;
}

.note-card strong { color: #3446a5; font-size: 17px; }
.note-card span { color: #606879; font-size: 14px; }

.article-body .next-step {
    margin-top: 74px;
    padding: 32px;
    border: 1px solid var(--line);
    border-radius: 18px;
    background: var(--soft);
}

.next-step h2 { font-size: 27px; }
.next-step p { margin-bottom: 16px; }

.text-link {
    color: var(--blue);
    font-size: 14px;
    font-weight: 700;
    text-decoration: none;
}

.text-link span { margin-left: 5px; }

.site-footer {
    min-height: 86px;
    display: flex;
    align-items: center;
    justify-content: space-between;
    padding: 20px max(24px, calc((100% - 1180px) / 2));
    border-top: 1px solid var(--line);
    color: #858b98;
    font-size: 12px;
}

.site-footer a { color: var(--ink); font-size: 15px; font-weight: 700; text-decoration: none; }

.blog-index { width: min(1180px, calc(100% - 48px)); margin: 0 auto; padding: 70px 0 100px; }
.blog-intro { max-width: 760px; margin: 0 auto 52px; text-align: center; }
.blog-intro h1 { margin-bottom: 16px; }
.blog-intro > p:last-child { color: var(--muted); font-size: 18px; }
.guide-grid { display: grid; grid-template-columns: repeat(3, minmax(0, 1fr)); gap: 18px; }
.guide-card { display: flex; min-height: 220px; flex-direction: column; align-items: flex-start; padding: 24px; border: 1px solid var(--line); border-radius: 16px; background: #fff; text-decoration: none; transition: transform .18s ease, box-shadow .18s ease, border-color .18s ease; }
.guide-card:hover { transform: translateY(-3px); border-color: #d8ddf3; box-shadow: 0 12px 30px rgba(28, 37, 70, .07); }
.guide-card > span { color: var(--blue); font-size: 10px; font-weight: 700; letter-spacing: .13em; }
.guide-card h2 { margin: 14px 0 8px; font-size: 20px; line-height: 1.3; letter-spacing: -.03em; }
.guide-card p { margin: 0 0 20px; color: var(--muted); font-size: 13px; line-height: 1.6; }
.guide-card b { margin-top: auto; color: var(--blue); font-size: 12px; }

@media (max-width: 760px) {
    .site-header, .article { width: min(100% - 36px, 620px); }
    .site-header { height: 70px; }
    .article-header { padding: 62px 0 32px; }
    .hero-frame { margin-bottom: 55px; }
    .hero-frame .image-placeholder { min-height: 280px; }
    .article-image { height: 280px; border-radius: 16px; }
    .image-placeholder { border-radius: 16px; }
    .article-layout { display: flex; flex-direction: column; gap: 25px; padding-bottom: 70px; }
    .contents { position: static; width: 100%; padding: 15px 18px; border: 1px solid var(--line); border-radius: 14px; }
    .contents a { padding: 5px 0; }
    .article-body section { margin: 42px 0; }
    .article-body .lead { font-size: 17px; }
    .article-body .image-placeholder, .article-body .image-placeholder--spatial { min-height: 230px; }
    .article-body .next-step { padding: 24px; }
    .site-footer { padding: 20px 18px; }
    .blog-index { width: min(100% - 36px, 620px); padding: 56px 0 70px; }
    .guide-grid { grid-template-columns: repeat(2, minmax(0, 1fr)); gap: 12px; }
    .guide-card { min-height: 210px; padding: 18px; }
}

@media (max-width: 420px) {
    .site-header nav { gap: 7px; font-size: 11px; }
    .brand img { width: 76px; }
    .article-header { padding-top: 48px; }
    h1 { font-size: 38px; }
    .hero-frame .image-placeholder { min-height: 230px; }
    .article-image { height: 230px; }
    .placeholder-note { padding: 0 12px; font-size: 12px; }
    .site-footer { align-items: flex-start; flex-direction: column; gap: 2px; justify-content: center; }
    .guide-grid { grid-template-columns: 1fr; }
    .guide-card { min-height: 175px; }
}