:root {
    --bg: #f7f8fa;
    --surface: #ffffff;
    --surface-subtle: #fafbfc;

    --text: #18202a;
    --text-soft: #65707e;
    --text-faint: #8a94a2;

    --border: #e4e8ed;
    --border-strong: #d6dce3;

    --accent: #315b7d;
    --accent-soft: #edf3f7;

    --danger: #a93c3c;
    --danger-soft: #fff1f1;

    --radius: 12px;

    --container: 1180px;
}


* {
    box-sizing: border-box;
}


html {
    -webkit-text-size-adjust: 100%;
}


body {
    margin: 0;

    background: var(--bg);

    color: var(--text);

    font-family:
        -apple-system,
        BlinkMacSystemFont,
        "Segoe UI",
        "Hiragino Kaku Gothic ProN",
        "Hiragino Sans",
        "Yu Gothic",
        Meiryo,
        sans-serif;

    font-size: 15px;
    line-height: 1.7;
}


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


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


.container {
    width: min(
        calc(100% - 40px),
        var(--container)
    );

    margin: 0 auto;
}


/* =========================================
   Header
========================================= */

.site-header {
    position: sticky;
    top: 0;
    z-index: 50;

    background:
        rgba(255, 255, 255, 0.94);

    border-bottom:
        1px solid var(--border);

    backdrop-filter:
        blur(10px);
}


.header-inner {
    min-height: 64px;

    display: flex;
    align-items: center;
    justify-content: space-between;
    gap: 24px;
}


.logo {
    display: inline-flex;
    align-items: center;
    gap: 9px;

    font-size: 18px;
    font-weight: 750;

    letter-spacing: -0.02em;
}


.logo-icon {
    width: 34px;
    height: 34px;

    display: grid;
    place-items: center;

    background:
        var(--accent-soft);

    color:
        var(--accent);

    border-radius: 9px;
}


.nav {
    display: flex;
    align-items: center;
    gap: 24px;

    color:
        var(--text-soft);

    font-size: 14px;
    font-weight: 600;
}


/* =========================================
   Hero
========================================= */

.hero {
    padding:
        72px 0 48px;
}


.hero-inner {
    max-width: 780px;
}


.eyebrow {
    margin-bottom: 12px;

    color:
        var(--accent);

    font-size: 13px;
    font-weight: 700;

    letter-spacing:
        0.04em;
}


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

    line-height: 1.35;

    letter-spacing:
        -0.025em;
}


h1 {
    margin-bottom: 18px;

    font-size:
        clamp(
            30px,
            5vw,
            46px
        );
}


h2 {
    font-size: 22px;
}


.hero-description {
    max-width: 700px;

    margin: 0;

    color:
        var(--text-soft);

    font-size: 17px;
}


/* =========================================
   Search
========================================= */

.search-box {
    display: flex;
    gap: 10px;

    margin-top: 30px;
}


.search-box input {
    width: 100%;
    height: 48px;

    padding: 0 16px;

    background:
        var(--surface);

    border:
        1px solid
        var(--border-strong);

    border-radius: 10px;

    color:
        var(--text);

    font-size: 15px;
}


.search-box button {
    height: 48px;

    padding: 0 22px;

    border: 0;
    border-radius: 10px;

    background:
        var(--text);

    color: #fff;

    font-weight: 700;

    cursor: pointer;
}


/* =========================================
   Stats
========================================= */

.stats {
    display: grid;

    grid-template-columns:
        repeat(2, minmax(0, 1fr));

    gap: 12px;

    margin-top: 28px;

    max-width: 520px;
}


.stat {
    padding: 16px 18px;

    background:
        var(--surface);

    border:
        1px solid var(--border);

    border-radius:
        var(--radius);
}


.stat-value {
    font-size: 24px;
    font-weight: 760;
}


.stat-label {
    color:
        var(--text-soft);

    font-size: 13px;
}


/* =========================================
   Section
========================================= */

.section {
    padding:
        22px 0 54px;
}


.section-header {
    display: flex;
    align-items: flex-end;
    justify-content: space-between;

    gap: 20px;

    margin-bottom: 18px;
}


.section-header h2 {
    margin-bottom: 3px;
}


.section-subtitle {
    margin: 0;

    color:
        var(--text-soft);
}


.more-link {
    color:
        var(--accent);

    font-weight: 650;
}


/* =========================================
   Cards
========================================= */

.card-grid {
    display: grid;

    grid-template-columns:
        repeat(3, minmax(0, 1fr));

    gap: 14px;
}


.card {
    display: block;

    padding: 18px;

    background:
        var(--surface);

    border:
        1px solid var(--border);

    border-radius:
        var(--radius);

    transition:
        border-color .15s ease,
        transform .15s ease;
}


.card:hover {
    color: inherit;

    border-color:
        var(--border-strong);

    transform:
        translateY(-1px);
}


.card-title {
    margin-bottom: 8px;

    font-size: 16px;
    font-weight: 720;
}


.card-meta {
    display: flex;
    flex-wrap: wrap;
    gap: 7px;

    margin-top: 12px;

    color:
        var(--text-soft);

    font-size: 12px;
}


.card-description {
    margin: 0;

    color:
        var(--text-soft);

    font-size: 14px;
}


/* =========================================
   Badge
========================================= */

.badges {
    display: flex;
    flex-wrap: wrap;
    gap: 7px;
}


.badge {
    display: inline-flex;
    align-items: center;

    padding: 4px 8px;

    border-radius: 999px;

    background:
        var(--surface-subtle);

    border:
        1px solid var(--border);

    color:
        var(--text-soft);

    font-size: 12px;
    font-weight: 650;
}


.badge-danger {
    background:
        var(--danger-soft);

    border-color:
        #f1caca;

    color:
        var(--danger);
}


/* =========================================
   Category grid
========================================= */

.category-grid {
    display: grid;

    grid-template-columns:
        repeat(4, minmax(0, 1fr));

    gap: 12px;
}


.category-card {
    padding: 17px;

    background:
        var(--surface);

    border:
        1px solid var(--border);

    border-radius:
        var(--radius);
}


.category-name {
    font-weight: 700;
}


.category-count {
    margin-top: 5px;

    color:
        var(--text-soft);

    font-size: 13px;
}


/* =========================================
   Listing
========================================= */

.page-header {
    padding:
        50px 0 24px;
}


.page-header h1 {
    margin-bottom: 8px;

    font-size: 34px;
}


.mail-list {
    display: grid;
    gap: 10px;
}


.mail-row {
    display: block;

    padding: 18px 20px;

    background:
        var(--surface);

    border:
        1px solid var(--border);

    border-radius:
        10px;
}


.mail-row:hover {
    color: inherit;

    border-color:
        var(--border-strong);
}


.mail-subject {
    margin-bottom: 7px;

    font-weight: 720;
}


.mail-meta {
    display: flex;
    flex-wrap: wrap;
    gap: 10px;

    color:
        var(--text-soft);

    font-size: 13px;
}


/* =========================================
   Detail
========================================= */

.detail-layout {
    display: grid;

    grid-template-columns:
        minmax(0, 1fr) 290px;

    gap: 28px;
}


.detail-card {
    padding: 24px;

    background:
        var(--surface);

    border:
        1px solid var(--border);

    border-radius:
        var(--radius);

    margin-bottom: 16px;
}


.detail-card h2 {
    margin-bottom: 16px;

    font-size: 18px;
}

.sender-note {
    margin: 14px 0 0;

    color: var(--text-soft);

    font-size: 12px;
    line-height: 1.7;
}

.auth-badge {
    display: inline-flex;
    align-items: center;

    padding: 3px 8px;

    border-radius: 999px;

    font-size: 12px;
    font-weight: 750;

    border: 1px solid var(--border);
}


.auth-pass {
    background: #eef8f0;
    color: #2f6d3a;
    border-color: #cfe7d4;
}


.auth-fail,
.auth-softfail {
    background: #fff1f1;
    color: #9a3434;
    border-color: #efcaca;
}


.auth-none,
.auth-neutral,
.auth-temperror,
.auth-permerror {
    background: #f5f6f8;
    color: #69727d;
    border-color: var(--border);
}


.auth-domain {
    margin-left: 8px;

    color: var(--text-soft);

    font-size: 12px;
}


.definition-list {
    margin: 0;
}


.definition-row {
    display: grid;

    grid-template-columns:
        150px minmax(0, 1fr);

    gap: 20px;

    padding: 11px 0;

    border-bottom:
        1px solid var(--border);
}


.definition-row:last-child {
    border-bottom: 0;
}


.definition-row dt {
    color:
        var(--text-soft);

    font-size: 13px;
}


.definition-row dd {
    margin: 0;

    overflow-wrap:
        anywhere;
}


.mail-body {
    white-space: pre-wrap;
    overflow-wrap: anywhere;

    font-size: 14px;
}


.url-text {
    overflow-wrap:
        anywhere;

    font-family:
        ui-monospace,
        SFMono-Regular,
        Menlo,
        Consolas,
        monospace;

    font-size: 12px;

    color:
        var(--text-soft);
}


.warning-box {
    padding: 18px;

    background:
        var(--danger-soft);

    border:
        1px solid #efd0d0;

    border-radius:
        var(--radius);

    color:
        #743030;
}


/* =========================================
   Pagination
========================================= */

.pagination {
    display: flex;
    justify-content: center;
    align-items: center;
    gap: 8px;

    padding:
        32px 0;
}


.pagination a,
.pagination span {
    padding:
        7px 11px;

    background:
        var(--surface);

    border:
        1px solid var(--border);

    border-radius:
        7px;

    font-size: 13px;
}


/* =========================================
   Footer
========================================= */

.footer {
    margin-top: 60px;

    padding:
        34px 0;

    background:
        var(--surface);

    border-top:
        1px solid var(--border);
}


.footer-inner {
    display: flex;
    justify-content: space-between;
    gap: 40px;

    color:
        var(--text-soft);

    font-size: 13px;
}


.footer p {
    max-width: 500px;

    margin:
        8px 0 0;
}


.footer-note {
    max-width: 400px;
}


/* =========================================
   Responsive
========================================= */

@media (
    max-width: 850px
) {

    .card-grid {
        grid-template-columns:
            repeat(2, minmax(0, 1fr));
    }

    .category-grid {
        grid-template-columns:
            repeat(2, minmax(0, 1fr));
    }

    .detail-layout {
        grid-template-columns: 1fr;
    }

}


@media (
    max-width: 600px
) {

    .container {
        width:
            min(
                calc(100% - 28px),
                var(--container)
            );
    }

    .header-inner {
        min-height: 58px;
    }

    .nav {
        gap: 13px;

        font-size: 12px;
    }

    .logo {
        font-size: 16px;
    }

    .logo-icon {
        width: 30px;
        height: 30px;
    }

    .hero {
        padding:
            48px 0 34px;
    }

    .hero-description {
        font-size: 15px;
    }

    .search-box {
        display: grid;
    }

    .search-box button {
        width: 100%;
    }

    .card-grid,
    .category-grid {
        grid-template-columns: 1fr;
    }

    .stats {
        grid-template-columns:
            repeat(2, 1fr);
    }

    .definition-row {
        grid-template-columns: 1fr;

        gap: 3px;
    }

    .footer-inner {
        display: grid;
    }

}