/* ===== Reset (軽量) ===== */
* {
    box-sizing: border-box;
}

html,
body {
    margin: 0;
    padding: 0;
}

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

a {
    color: inherit;
    text-decoration: none;
}

/* ===== Design Tokens ===== */
:root {
    --maxw: 1040px;
    --bg: #fafafa;
    --panel: #ffffff;
    --text: #222;
    --muted: #5b5b5b;
    --brand: #1f6feb;
    --chip-bg: #f1f5ff;
    --chip-bd: #cfe0ff;
    --radius: 12px;
    --shadow: 0 10px 30px rgba(0, 0, 0, .08);
    --shadow-hover: 0 12px 36px rgba(0, 0, 0, .12);
    --gap: 20px;
}

/* ===== Base ===== */
body {
    font-family: -apple-system, BlinkMacSystemFont, "Segoe UI", Roboto, "Hiragino Kaku Gothic ProN", "Noto Sans JP", "Helvetica Neue", Arial, "メイリオ", Meiryo, sans-serif;
    color: var(--text);
    background: var(--bg);
    line-height: 1.65;
}

/* Containers */
.container {
    max-width: var(--maxw);
    margin: 0 auto;
    padding: 0 16px;
}

.stack>*+* {
    margin-top: 16px;
}

/* ===== Header（共通） ===== */
.site-header {
    position: sticky;
    top: 0;
    z-index: 50;
    background: rgba(255, 255, 255, .9);
    backdrop-filter: saturate(180%) blur(8px);
    border-bottom: 1px solid #eee;
}

.header-inner {
    display: flex;
    align-items: center;
    justify-content: space-between;
    min-height: 56px;
}

.brand {
    font-weight: 700;
    letter-spacing: .02em;
    color: var(--brand);
}

.nav a {
    margin-left: 16px;
    color: #333;
    font-weight: 500;
}

.nav a:hover {
    color: var(--brand);
}

/* ===== Section Title（共通見出し） ===== */
.section-title {
    margin: 28px 0 12px;
    font-size: 18px;
    color: #333;
}

/* ===== Footer（共通） ===== */
.site-footer {
    margin-top: 40px;
    border-top: 1px solid #eee;
    background: #fff;
}

.footer-inner {
    min-height: 64px;
    display: flex;
    align-items: center;
    justify-content: space-between;
}

.site-footer .nav a {
    color: #666;
}

.site-footer .nav a:hover {
    color: var(--brand);
}