[hidden] {
    display: none !important;
}

.visually-hidden {
    position: absolute;
    width: 1px;
    height: 1px;
    padding: 0;
    overflow: hidden;
    clip: rect(0, 0, 0, 0);
    white-space: nowrap;
    border: 0;
}

.email-page.dialog-open {
    overflow: hidden;
}

.email-page button,
.email-page summary {
    font: inherit;
}

.email-page button:focus-visible,
.email-page summary:focus-visible,
.email-page dialog:focus-visible {
    outline: 3px solid rgba(8, 127, 174, 0.34);
    outline-offset: 4px;
}

.nav-links a[aria-current="page"] {
    background: var(--surface-blue);
    color: var(--brand-dark);
}

.nav-banner a[aria-current="page"],
.footer-links a[aria-current="page"] {
    color: #72d0e4;
}

#welcome,
#email-guides,
[data-email-guide],
.guide-steps,
.legacy-archive section {
    scroll-margin-top: calc(var(--header-height) + 28px);
}

.email-hero {
    position: relative;
    isolation: isolate;
    overflow: hidden;
    padding: clamp(76px, 9vw, 116px) 0 clamp(72px, 8vw, 104px);
    background:
        radial-gradient(circle at 4% 8%, rgba(71, 189, 216, 0.21), transparent 28%),
        radial-gradient(circle at 96% 92%, rgba(8, 127, 174, 0.13), transparent 29%),
        linear-gradient(135deg, #f8fbfd 0%, #ffffff 55%, #edf7fa 100%);
}

.email-hero::before {
    position: absolute;
    inset: 0;
    z-index: -1;
    background-image:
        linear-gradient(rgba(8, 127, 174, 0.045) 1px, transparent 1px),
        linear-gradient(90deg, rgba(8, 127, 174, 0.045) 1px, transparent 1px);
    background-size: 44px 44px;
    content: "";
    mask-image: linear-gradient(to bottom, #000, transparent 88%);
}

.email-hero-grid {
    display: grid;
    grid-template-columns: minmax(0, 1.02fr) minmax(430px, 0.98fr);
    align-items: center;
    gap: clamp(54px, 8vw, 102px);
}

.email-hero h1 {
    max-width: 760px;
    margin: 0;
    color: var(--ink-950);
    font-size: clamp(3rem, 5.15vw, 4.9rem);
    font-weight: 760;
    letter-spacing: -0.06em;
    line-height: 1;
}

.email-hero-lead {
    max-width: 650px;
    margin: 28px 0 0;
    color: var(--slate-600);
    font-size: clamp(1.06rem, 1.5vw, 1.2rem);
    line-height: 1.75;
}

.mail-console {
    position: relative;
    min-height: 520px;
    padding: 26px;
    overflow: hidden;
    border: 1px solid rgba(255, 255, 255, 0.16);
    border-radius: 26px;
    background:
        radial-gradient(circle at 100% 0%, rgba(71, 189, 216, 0.22), transparent 36%),
        linear-gradient(145deg, var(--ink-950), #102e48);
    box-shadow: var(--shadow-lg);
    color: #ffffff;
}

.mail-console::before {
    position: absolute;
    right: -130px;
    bottom: -160px;
    width: 410px;
    height: 410px;
    border: 74px solid rgba(71, 189, 216, 0.07);
    border-radius: 50%;
    content: "";
}

.mail-console-toolbar,
.mail-console-footer {
    position: relative;
    z-index: 1;
    display: flex;
    align-items: center;
    justify-content: space-between;
    gap: 18px;
    color: #adc3d1;
    font-size: 0.7rem;
    font-weight: 760;
    letter-spacing: 0.08em;
    text-transform: uppercase;
}

.mail-console-toolbar {
    padding-bottom: 20px;
    border-bottom: 1px solid rgba(255, 255, 255, 0.11);
}

.mail-window-dots {
    display: flex;
    gap: 6px;
}

.mail-window-dots i {
    width: 7px;
    height: 7px;
    border-radius: 50%;
    background: rgba(255, 255, 255, 0.3);
}

.mail-window-dots i:first-child {
    background: var(--accent);
}

.mail-window-dots i:nth-child(2) {
    background: #f4bf4f;
}

.mail-window-dots i:last-child {
    background: #55dda8;
}

.mail-status {
    display: inline-flex;
    align-items: center;
    gap: 8px;
    color: #dce9ef;
}

.mail-status i,
.mail-pulse {
    width: 8px;
    height: 8px;
    border-radius: 50%;
    background: #55dda8;
    box-shadow: 0 0 0 4px rgba(85, 221, 168, 0.14);
}

.mail-account-row {
    position: relative;
    z-index: 1;
    display: grid;
    grid-template-columns: auto 1fr auto;
    align-items: center;
    gap: 15px;
    margin: 28px 0 14px;
    padding: 18px;
    border: 1px solid rgba(255, 255, 255, 0.14);
    border-radius: 13px;
    background: rgba(255, 255, 255, 0.07);
}

.mail-avatar {
    display: grid;
    width: 44px;
    height: 44px;
    place-items: center;
    border-radius: 11px;
    background: rgba(71, 189, 216, 0.16);
    color: #7bd8eb;
    font-size: 1.2rem;
    font-weight: 800;
}

.mail-account-row small,
.mail-account-row strong {
    display: block;
}

.mail-account-row small {
    color: #91a9b9;
    font-size: 0.65rem;
    font-weight: 800;
    letter-spacing: 0.09em;
    text-transform: uppercase;
}

.mail-account-row strong {
    margin-top: 2px;
    color: #ffffff;
    font-size: 0.93rem;
    font-weight: 680;
}

.mail-check {
    display: grid;
    width: 29px;
    height: 29px;
    place-items: center;
    border-radius: 50%;
    background: rgba(85, 221, 168, 0.12);
    color: #65e2b1;
}

.mail-settings {
    position: relative;
    z-index: 1;
    display: grid;
    gap: 9px;
}

.mail-setting {
    display: grid;
    min-height: 76px;
    grid-template-columns: auto 1fr auto;
    align-items: center;
    gap: 16px;
    padding: 15px 16px;
    border: 1px solid rgba(255, 255, 255, 0.1);
    border-radius: 11px;
    background: rgba(255, 255, 255, 0.045);
}

.setting-index {
    color: #70cfe3;
    font-family: ui-monospace, SFMono-Regular, Menlo, Consolas, monospace;
    font-size: 0.72rem;
    font-weight: 800;
}

.mail-setting small,
.mail-setting strong {
    display: block;
}

.mail-setting small {
    color: #91a8b9;
    font-size: 0.66rem;
    font-weight: 800;
    letter-spacing: 0.08em;
    text-transform: uppercase;
}

.mail-setting strong {
    margin-top: 3px;
    color: #ffffff;
    font-size: 0.94rem;
}

.mail-setting > span:last-child {
    color: #aec0cc;
    font-size: 0.72rem;
}

.mail-console-footer {
    margin-top: 23px;
    padding-top: 18px;
    border-top: 1px solid rgba(255, 255, 255, 0.1);
}

.email-intro {
    background: #ffffff;
}

.section-intro,
.guide-picker-heading > p,
.library-heading > p {
    margin: 0;
    color: var(--slate-600);
    font-size: 1.02rem;
    line-height: 1.7;
}

.setup-foundation-grid {
    display: grid;
    grid-template-columns: minmax(0, 1fr) minmax(0, 0.84fr);
    gap: 18px;
}

.foundation-card {
    min-height: 410px;
    padding: clamp(30px, 4vw, 46px);
    border: 1px solid var(--line);
    border-radius: 19px;
    background: #ffffff;
    box-shadow: 0 18px 48px rgba(11, 31, 51, 0.055);
}

.foundation-note {
    background:
        radial-gradient(circle at 100% 100%, rgba(71, 189, 216, 0.11), transparent 35%),
        var(--surface-soft);
}

.foundation-card-heading {
    display: flex;
    align-items: flex-start;
    gap: 17px;
    padding-bottom: 24px;
    border-bottom: 1px solid var(--line);
}

.foundation-card-heading > span {
    color: var(--brand-dark);
    font-family: ui-monospace, SFMono-Regular, Menlo, Consolas, monospace;
    font-size: 0.76rem;
    font-weight: 800;
}

.foundation-card-heading .section-label {
    margin-bottom: 4px;
}

.foundation-card h3 {
    margin: 0;
    color: var(--ink-900);
    font-size: clamp(1.4rem, 2.4vw, 1.85rem);
    letter-spacing: -0.035em;
}

.foundation-checklist ul {
    display: grid;
    gap: 0;
    margin: 14px 0 0;
    padding: 0;
    list-style: none;
}

.foundation-checklist li {
    display: flex;
    justify-content: space-between;
    gap: 24px;
    padding: 13px 0;
    border-bottom: 1px solid var(--line);
    color: var(--slate-600);
    font-size: 0.96rem;
}

.foundation-checklist li:last-child {
    border-bottom: 0;
}

.foundation-checklist strong {
    color: var(--ink-900);
    font-weight: 680;
    text-align: right;
}

.foundation-note > p {
    margin: 24px 0 0;
    color: var(--slate-600);
    font-size: 0.98rem;
    line-height: 1.7;
}

.settings-rule {
    display: grid;
    grid-template-columns: auto 1fr;
    gap: 13px;
    margin-top: 22px;
    padding: 17px;
    border: 1px solid #bddce7;
    border-radius: 12px;
    background: #ffffff;
}

.settings-rule > span {
    display: grid;
    width: 24px;
    height: 24px;
    place-items: center;
    border-radius: 50%;
    background: var(--brand);
    color: #ffffff;
    font-size: 0.75rem;
    font-weight: 900;
}

.settings-rule p {
    margin: 0;
    color: var(--ink-900);
    font-size: 0.94rem;
    font-weight: 650;
}

.foundation-note > a {
    display: inline-flex;
    gap: 8px;
    margin-top: 23px;
    color: var(--brand-dark);
    font-size: 0.96rem;
    font-weight: 760;
    text-decoration: none;
}

.guide-picker-heading,
.library-heading {
    display: grid;
    grid-template-columns: minmax(0, 0.92fr) minmax(300px, 0.58fr);
    align-items: end;
    gap: 42px;
}

.guide-picker-heading {
    margin: clamp(70px, 9vw, 110px) 0 32px;
}

.guide-picker-heading h2,
.library-heading h2 {
    margin: 0;
    color: var(--ink-900);
    font-size: clamp(2rem, 4vw, 3.1rem);
    letter-spacing: -0.05em;
    line-height: 1.08;
}

.guide-picker-grid {
    display: grid;
    grid-template-columns: repeat(3, 1fr);
    gap: 16px;
}

.guide-picker-card {
    position: relative;
    display: flex;
    min-height: 230px;
    flex-direction: column;
    padding: 28px;
    overflow: hidden;
    border: 1px solid var(--line);
    border-radius: 15px;
    background: #ffffff;
    text-decoration: none;
    transition: transform 180ms ease, border-color 180ms ease, box-shadow 180ms ease;
}

.guide-picker-card:hover {
    border-color: #aac9d7;
    box-shadow: var(--shadow-sm);
    transform: translateY(-3px);
}

.guide-picker-card[aria-current="true"] {
    border-color: transparent;
    background:
        radial-gradient(circle at 105% 110%, rgba(71, 189, 216, 0.22), transparent 42%),
        var(--ink-950);
    color: #ffffff;
}

.guide-picker-card.legacy::after {
    position: absolute;
    top: 19px;
    right: 19px;
    padding: 4px 8px;
    border-radius: 999px;
    background: #f0f3f5;
    color: var(--slate-600);
    content: "Legacy";
    font-size: 0.68rem;
    font-weight: 850;
    letter-spacing: 0.08em;
    text-transform: uppercase;
}

.picker-platform {
    color: var(--brand-dark);
    font-size: 0.76rem;
    font-weight: 850;
    letter-spacing: 0.1em;
    text-transform: uppercase;
}

.guide-picker-card[aria-current="true"] .picker-platform {
    color: #72d0e4;
}

.guide-picker-card h3 {
    margin: 36px 0 6px;
    color: var(--ink-900);
    font-size: 1.42rem;
    letter-spacing: -0.025em;
}

.guide-picker-card[aria-current="true"] h3 {
    color: #ffffff;
}

.guide-picker-card p {
    margin: 0;
    color: var(--slate-600);
    font-size: 0.92rem;
}

.guide-picker-card[aria-current="true"] p {
    color: #a9bfcc;
}

.picker-arrow {
    margin-top: auto;
    color: var(--brand-dark);
    font-size: 1.1rem;
}

.guide-picker-card[aria-current="true"] .picker-arrow {
    color: #72d0e4;
}

.email-library {
    padding: clamp(82px, 10vw, 126px) 0;
    border-top: 1px solid var(--line);
    background: var(--surface-soft);
}

.library-heading {
    margin-bottom: 44px;
}

.guide-directory-toggle {
    display: none;
}

.email-library-layout {
    display: grid;
    grid-template-columns: 280px minmax(0, 1fr);
    align-items: start;
    gap: clamp(30px, 4vw, 54px);
}

.email-guide-sidebar {
    position: sticky;
    top: calc(var(--header-height) + 22px);
    max-height: calc(100vh - var(--header-height) - 44px);
    padding: 24px;
    overflow-y: auto;
    border: 1px solid var(--line);
    border-radius: 16px;
    background: #ffffff;
    box-shadow: var(--shadow-sm);
}

.sidebar-heading {
    margin-bottom: 18px;
    padding: 2px 3px 18px;
    border-bottom: 1px solid var(--line);
}

.sidebar-heading p {
    margin: 0 0 4px;
    color: var(--brand-dark);
    font-size: 0.72rem;
    font-weight: 850;
    letter-spacing: 0.11em;
    text-transform: uppercase;
}

.sidebar-heading h2 {
    margin: 0;
    color: var(--ink-900);
    font-size: 1.35rem;
    letter-spacing: -0.03em;
}

.category {
    display: flex;
    width: 100%;
    align-items: center;
    justify-content: space-between;
    gap: 12px;
    padding: 11px 3px;
    border: 0;
    background: transparent;
    color: var(--slate-700);
    cursor: pointer;
    font-size: 0.77rem;
    font-weight: 850;
    letter-spacing: 0.08em;
    text-align: left;
    text-transform: uppercase;
}

.category:hover {
    color: var(--brand-dark);
}

.category-chevron,
.directory-toggle-icon {
    position: relative;
    width: 17px;
    height: 17px;
    flex: 0 0 auto;
}

.category-chevron::before,
.category-chevron::after,
.directory-toggle-icon::before,
.directory-toggle-icon::after {
    position: absolute;
    top: 8px;
    left: 4px;
    width: 9px;
    border-top: 1.5px solid currentColor;
    content: "";
    transition: transform 180ms ease;
}

.category-chevron::after,
.directory-toggle-icon::after {
    transform: rotate(90deg);
}

.category[aria-expanded="true"] .category-chevron::after,
.guide-directory-toggle[aria-expanded="true"] .directory-toggle-icon::after {
    transform: rotate(0);
}

.subcategory {
    max-height: 0;
    overflow: hidden;
    opacity: 0;
    transition: max-height 240ms ease, opacity 180ms ease;
}

.subcategory.open {
    max-height: 520px;
    padding-bottom: 8px;
    opacity: 1;
}

.subcategory a {
    display: grid;
    gap: 1px;
    margin: 2px 0;
    padding: 10px 11px;
    overflow: hidden;
    border-radius: 8px;
    color: var(--slate-600);
    font-size: 0.9rem;
    font-weight: 680;
    line-height: 1.35;
    text-decoration: none;
    transition: background-color 160ms ease, color 160ms ease;
}

.subcategory a span {
    color: var(--slate-400);
    font-size: 0.72rem;
    font-weight: 650;
}

.subcategory a:hover {
    background: var(--surface-soft);
    color: var(--ink-900);
}

.subcategory a.active,
.subcategory a[aria-current="true"] {
    background: var(--surface-blue);
    color: var(--brand-dark);
}

.subcategory a.active span,
.subcategory a[aria-current="true"] span {
    color: #4089a6;
}

.sidebar-assist {
    display: grid;
    gap: 7px;
    margin-top: 16px;
    padding: 16px;
    border-radius: 11px;
    background: var(--ink-950);
    color: #ffffff;
}

.sidebar-assist > span {
    color: #a9bfcc;
    font-size: 0.8rem;
}

.sidebar-assist a {
    color: #ffffff;
    font-size: 0.86rem;
    font-weight: 760;
    text-decoration: none;
}

.email-guide-content {
    min-width: 0;
}

.email-guide {
    min-width: 0;
    padding: clamp(28px, 4vw, 48px);
    border: 1px solid var(--line);
    border-radius: 20px;
    background: #ffffff;
    box-shadow: 0 20px 55px rgba(11, 31, 51, 0.06);
}

.guide-header {
    display: grid;
    grid-template-columns: minmax(0, 1fr) auto;
    align-items: start;
    gap: 34px;
    padding-bottom: 32px;
    border-bottom: 1px solid var(--line);
}

.guide-header h2 {
    margin: 0;
    color: var(--ink-900);
    font-size: clamp(2.1rem, 4vw, 3.25rem);
    letter-spacing: -0.052em;
    line-height: 1.04;
}

.guide-header > div:first-child > p:last-child {
    max-width: 690px;
    margin: 18px 0 0;
    color: var(--slate-600);
    font-size: 1rem;
    line-height: 1.72;
}

.guide-meta {
    display: grid;
    min-width: 150px;
    justify-items: end;
    gap: 8px;
}

.guide-meta span {
    padding: 6px 9px;
    border-radius: 999px;
    background: var(--surface-blue);
    color: var(--brand-dark);
    font-size: 0.7rem;
    font-weight: 850;
    letter-spacing: 0.08em;
    text-transform: uppercase;
}

.guide-meta strong {
    color: var(--slate-600);
    font-size: 0.8rem;
    font-weight: 680;
    text-align: right;
}

.guide-notice,
.support-warning,
.legacy-banner {
    display: grid;
    grid-template-columns: 165px 1fr;
    gap: 20px;
    margin-top: 24px;
    padding: 17px 19px;
    border: 1px solid #c7e0e9;
    border-radius: 12px;
    background: #f0f9fb;
}

.guide-notice strong,
.support-warning strong,
.legacy-banner strong {
    color: var(--brand-dark);
    font-size: 0.8rem;
    font-weight: 850;
    letter-spacing: 0.07em;
    text-transform: uppercase;
}

.guide-notice p,
.support-warning p,
.legacy-banner p {
    margin: 0;
    color: var(--slate-600);
    font-size: 0.92rem;
}

.guide-notice p a {
    color: currentColor;
    font-weight: 760;
    text-underline-offset: 3px;
}

.guide-notice-cloud {
    border-color: #d8d3ef;
    background: #f7f5fc;
}

.guide-notice-cloud strong {
    color: #5b4d94;
}

.setup-prerequisites,
.legacy-archive {
    margin-top: 24px;
    border: 1px solid var(--line);
    border-radius: 14px;
    background: #ffffff;
}

.setup-prerequisites > summary,
.legacy-archive > summary {
    display: flex;
    min-height: 68px;
    align-items: center;
    justify-content: space-between;
    gap: 24px;
    padding: 17px 20px;
    color: var(--ink-900);
    cursor: pointer;
    font-size: 1rem;
    font-weight: 760;
    list-style: none;
}

.setup-prerequisites > summary::-webkit-details-marker,
.legacy-archive > summary::-webkit-details-marker {
    display: none;
}

.setup-prerequisites > summary::after,
.legacy-archive > summary::after {
    display: grid;
    width: 28px;
    height: 28px;
    flex: 0 0 auto;
    place-items: center;
    border-radius: 50%;
    background: var(--surface-soft);
    color: var(--brand-dark);
    content: "+";
    font-size: 1rem;
}

.setup-prerequisites[open] > summary::after,
.legacy-archive[open] > summary::after {
    content: "−";
}

.details-hint {
    margin-left: auto;
    color: var(--slate-400);
    font-size: 0.78rem;
    font-weight: 650;
}

.prerequisites-body {
    padding: 0 20px 22px;
    border-top: 1px solid var(--line);
}

.prerequisites-body > p {
    margin: 20px 0 0;
    color: var(--slate-600);
    font-size: 1rem;
    line-height: 1.7;
}

.settings-caution {
    display: grid;
    grid-template-columns: auto 1fr;
    gap: 15px;
    margin: 18px 0;
    padding: 15px;
    border-left: 3px solid var(--brand);
    border-radius: 0 9px 9px 0;
    background: var(--surface-blue);
}

.settings-caution strong {
    color: var(--brand-dark);
    font-size: 0.8rem;
    text-transform: uppercase;
}

.settings-caution span {
    color: var(--slate-600);
    font-size: 0.9rem;
}

.table-scroll {
    max-width: 100%;
    margin: 18px 0;
    overflow-x: auto;
    border: 1px solid var(--line);
    border-radius: 11px;
    background: #ffffff;
}

.email-guide table {
    width: 100%;
    min-width: 620px;
    border-collapse: collapse;
    font-size: 0.9rem;
}

.email-guide th,
.email-guide td {
    padding: 13px 15px;
    border-right: 1px solid var(--line);
    border-bottom: 1px solid var(--line);
    text-align: left;
    vertical-align: top;
}

.email-guide th:last-child,
.email-guide td:last-child {
    border-right: 0;
}

.email-guide tr:last-child td {
    border-bottom: 0;
}

.email-guide thead th {
    background: var(--surface-soft);
    color: var(--ink-900);
    font-size: 0.76rem;
    font-weight: 850;
    letter-spacing: 0.06em;
    text-transform: uppercase;
}

.email-guide tbody tr:nth-child(even) {
    background: #fafcfd;
}

.guide-subnav {
    display: flex;
    flex-wrap: wrap;
    align-items: center;
    gap: 8px;
    margin: 22px 0 0;
    padding: 14px;
    border: 1px solid var(--line);
    border-radius: 11px;
    background: var(--surface-soft);
}

.guide-subnav p {
    width: 100%;
    margin: 0 0 3px;
    color: var(--slate-400);
    font-size: 0.72rem;
    font-weight: 850;
    letter-spacing: 0.08em;
    text-transform: uppercase;
}

.guide-subnav a {
    padding: 9px 12px;
    border: 1px solid var(--line);
    border-radius: 8px;
    background: #ffffff;
    color: var(--brand-dark);
    font-size: 0.86rem;
    font-weight: 720;
    text-decoration: none;
}

.guide-subnav a:hover {
    border-color: #a8ccda;
}

.guide-steps {
    margin-top: 34px;
}

.guide-steps > hr,
.legacy-archive hr {
    display: none;
}

.guide-steps > h3 {
    margin: 0 0 18px;
    color: var(--ink-900);
    font-size: 1.3rem;
    letter-spacing: -0.025em;
}

.guide-step {
    position: relative;
    margin-top: 16px;
    padding: clamp(22px, 4vw, 34px);
    border: 1px solid var(--line);
    border-radius: 15px;
    background: #ffffff;
}

.guide-step > h2:first-child {
    display: inline-flex;
    align-items: center;
    min-height: 28px;
    margin: 0 0 14px;
    padding: 5px 9px;
    border-radius: 7px;
    background: var(--surface-blue);
    color: var(--brand-dark);
    font-family: ui-monospace, SFMono-Regular, Menlo, Consolas, monospace;
    font-size: 0.78rem;
    font-weight: 850;
    letter-spacing: 0.06em;
    text-transform: uppercase;
}

.guide-step h3,
.guide-step h2:not(:first-child) {
    margin: 10px 0;
    color: var(--ink-900);
    font-size: 1.2rem;
    letter-spacing: -0.02em;
}

.guide-step h2:not(:first-child) {
    margin-top: 28px;
    padding-top: 22px;
    border-top: 1px solid var(--line);
    color: var(--brand-dark);
}

.guide-step p {
    max-width: 760px;
    margin: 9px 0 0;
    color: var(--slate-600);
    font-size: 1rem;
    line-height: 1.72;
}

.guide-step p + p {
    margin-top: 13px;
    padding: 13px 15px;
    border-left: 3px solid #9bc8d8;
    border-radius: 0 8px 8px 0;
    background: var(--surface-soft);
    font-size: 0.92rem;
}

.screenshot-button {
    display: block;
    width: min(100%, 880px);
    margin: 24px auto 0;
    padding: 13px;
    border: 1px solid var(--line);
    border-radius: 13px;
    background:
        linear-gradient(45deg, #f2f5f7 25%, transparent 25%),
        linear-gradient(-45deg, #f2f5f7 25%, transparent 25%),
        linear-gradient(45deg, transparent 75%, #f2f5f7 75%),
        linear-gradient(-45deg, transparent 75%, #f2f5f7 75%),
        #fafcfd;
    background-position: 0 0, 0 8px, 8px -8px, -8px 0;
    background-size: 16px 16px;
    cursor: zoom-in;
    transition: border-color 180ms ease, box-shadow 180ms ease, transform 180ms ease;
}

.screenshot-button:hover {
    border-color: #9dc5d4;
    box-shadow: 0 16px 40px rgba(11, 31, 51, 0.1);
    transform: translateY(-2px);
}

.screenshot-button img {
    width: auto;
    max-width: 100%;
    height: auto;
    max-height: 820px;
    margin: 0 auto;
    object-fit: contain;
}

.screenshot-button.is-portrait {
    width: min(100%, 500px);
}

.screenshot-button.is-compact {
    width: fit-content;
    min-width: 112px;
}

.screenshot-button.is-compact img {
    image-rendering: auto;
}

.screenshot-button::after {
    display: block;
    margin-top: 10px;
    padding-top: 9px;
    border-top: 1px solid rgba(220, 229, 236, 0.9);
    background: rgba(255, 255, 255, 0.88);
    color: var(--slate-600);
    content: "Open full-size screenshot";
    font-size: 0.78rem;
    font-weight: 720;
    text-align: center;
}

.current-checklist {
    margin-top: 26px;
    padding: clamp(24px, 4vw, 38px);
    border-radius: 16px;
    background:
        radial-gradient(circle at 100% 0%, rgba(71, 189, 216, 0.18), transparent 34%),
        var(--ink-950);
    color: #ffffff;
}

.checklist-heading .section-label {
    color: #72d0e4;
}

.checklist-heading h3 {
    margin: 0;
    color: #ffffff;
    font-size: clamp(1.5rem, 3vw, 2.2rem);
    letter-spacing: -0.04em;
}

.current-checklist ol {
    display: grid;
    grid-template-columns: 1fr 1fr;
    gap: 0 28px;
    margin: 28px 0 0;
    padding: 0;
    counter-reset: checks;
    list-style: none;
}

.current-checklist li {
    position: relative;
    display: grid;
    min-height: 88px;
    align-content: center;
    padding: 17px 0 17px 44px;
    border-top: 1px solid rgba(255, 255, 255, 0.12);
    counter-increment: checks;
}

.current-checklist li::before {
    position: absolute;
    top: 21px;
    left: 0;
    display: grid;
    width: 27px;
    height: 27px;
    place-items: center;
    border-radius: 50%;
    background: rgba(71, 189, 216, 0.14);
    color: #72d0e4;
    content: counter(checks);
    font-size: 0.75rem;
    font-weight: 850;
}

.current-checklist strong,
.current-checklist span {
    display: block;
}

.current-checklist strong {
    color: #ffffff;
    font-size: 1rem;
}

.current-checklist span {
    margin-top: 3px;
    color: #9fb5c4;
    font-size: 0.88rem;
}

.support-warning {
    border-color: #efd4b4;
    background: #fff9f2;
}

.support-warning strong {
    color: #9a5a16;
}

.legacy-archive {
    overflow: clip;
}

.legacy-archive > summary {
    min-height: 88px;
    padding: 20px 22px;
}

.legacy-archive > summary > span:first-child {
    display: grid;
    gap: 4px;
}

.legacy-archive > summary small {
    color: #9a5a16;
    font-size: 0.7rem;
    font-weight: 850;
    letter-spacing: 0.1em;
    text-transform: uppercase;
}

.legacy-archive-body {
    padding: 0 clamp(20px, 4vw, 34px) 34px;
    border-top: 1px solid var(--line);
}

.legacy-banner {
    margin: 24px 0;
    border-color: #efd4b4;
    background: #fff9f2;
}

.legacy-banner strong {
    color: #9a5a16;
}

.faq-nav {
    display: flex;
    flex-wrap: wrap;
    gap: 8px;
    margin: 18px 0 28px;
}

.faq-nav-btn {
    padding: 9px 12px;
    border: 1px solid var(--line);
    border-radius: 8px;
    background: #ffffff;
    color: var(--brand-dark);
    cursor: pointer;
    font-size: 0.86rem;
    font-weight: 720;
}

.faq-nav-btn:hover {
    border-color: #9dc5d4;
    background: var(--surface-blue);
}

.legacy-archive section {
    margin-top: 42px;
    padding-top: 34px;
    border-top: 1px solid var(--line);
}

.legacy-archive section:first-of-type {
    margin-top: 0;
}

.legacy-archive section > h2 {
    margin: 0;
    color: var(--ink-900);
    font-size: clamp(1.5rem, 3vw, 2.1rem);
    letter-spacing: -0.035em;
}

.legacy-archive section > h3 {
    margin: 30px 0 8px;
    color: var(--ink-900);
    font-size: 1.02rem;
}

.legacy-archive section > p {
    margin: 11px 0 0;
    color: var(--slate-600);
    font-size: 0.96rem;
    line-height: 1.7;
}

.email-cta {
    padding: clamp(78px, 10vw, 124px) 0;
    background: #ffffff;
}

.screenshot-dialog {
    width: min(94vw, 1500px);
    max-width: none;
    max-height: 94vh;
    margin: auto;
    padding: 0;
    overflow: hidden;
    border: 1px solid rgba(255, 255, 255, 0.14);
    border-radius: 17px;
    background: #081a2b;
    box-shadow: 0 36px 100px rgba(0, 0, 0, 0.42);
    color: #ffffff;
}

.screenshot-dialog[open] {
    display: grid;
    grid-template-rows: auto minmax(0, 1fr) auto;
}

.screenshot-dialog::backdrop {
    background: rgba(2, 11, 20, 0.82);
    backdrop-filter: blur(7px);
}

.dialog-toolbar {
    display: flex;
    align-items: center;
    justify-content: space-between;
    gap: 24px;
    padding: 18px 20px;
    border-bottom: 1px solid rgba(255, 255, 255, 0.12);
}

.dialog-toolbar p {
    margin: 0;
    color: #72d0e4;
    font-size: 0.7rem;
    font-weight: 850;
    letter-spacing: 0.1em;
    text-transform: uppercase;
}

.dialog-toolbar h2 {
    margin: 2px 0 0;
    color: #ffffff;
    font-size: 1.02rem;
    font-weight: 680;
}

.dialog-toolbar button {
    display: grid;
    width: 42px;
    height: 42px;
    flex: 0 0 auto;
    place-items: center;
    border: 1px solid rgba(255, 255, 255, 0.18);
    border-radius: 9px;
    background: rgba(255, 255, 255, 0.08);
    color: #ffffff;
    cursor: pointer;
    font-size: 1.5rem;
    line-height: 1;
}

.dialog-canvas {
    display: grid;
    min-height: 0;
    place-items: center;
    padding: 18px;
    overflow: auto;
    background:
        linear-gradient(45deg, rgba(255, 255, 255, 0.025) 25%, transparent 25%),
        linear-gradient(-45deg, rgba(255, 255, 255, 0.025) 25%, transparent 25%),
        #06121f;
    background-position: 0 0, 10px 10px;
    background-size: 20px 20px;
}

.dialog-canvas img {
    width: auto;
    max-width: 100%;
    height: auto;
    max-height: 76vh;
    object-fit: contain;
}

.dialog-caption {
    margin: 0;
    padding: 12px 20px;
    border-top: 1px solid rgba(255, 255, 255, 0.1);
    color: #9fb5c4;
    font-size: 0.84rem;
}

.return-to-top {
    position: fixed;
    right: 22px;
    bottom: 22px;
    z-index: 800;
    display: inline-flex;
    min-width: 58px;
    min-height: 48px;
    align-items: center;
    justify-content: center;
    gap: 6px;
    padding: 10px 13px;
    border: 1px solid rgba(255, 255, 255, 0.15);
    border-radius: 10px;
    background: var(--ink-950);
    box-shadow: 0 12px 30px rgba(7, 22, 38, 0.22);
    color: #ffffff;
    cursor: pointer;
    font-size: 0.82rem;
    font-weight: 760;
    opacity: 0;
    pointer-events: none;
    transform: translateY(18px);
    transition: opacity 180ms ease, transform 180ms ease, background-color 180ms ease;
}

.return-to-top.visible {
    opacity: 1;
    pointer-events: auto;
    transform: translateY(0);
}

.return-to-top:hover {
    background: var(--brand-dark);
}

@media (max-width: 1080px) {
    .email-hero-grid {
        grid-template-columns: 1fr;
    }

    .email-hero-copy {
        max-width: 800px;
    }

    .mail-console {
        width: min(100%, 760px);
    }

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

@media (max-width: 920px) {
    .guide-directory-toggle {
        position: sticky;
        top: calc(var(--header-height) + 10px);
        z-index: 610;
        display: flex;
        width: 100%;
        min-height: 68px;
        align-items: center;
        justify-content: space-between;
        gap: 20px;
        margin-bottom: 18px;
        padding: 13px 17px;
        border: 1px solid var(--line);
        border-radius: 12px;
        background: rgba(255, 255, 255, 0.98);
        box-shadow: var(--shadow-sm);
        color: var(--ink-900);
        cursor: pointer;
        text-align: left;
        backdrop-filter: blur(12px);
    }

    .guide-directory-toggle small,
    .guide-directory-toggle strong {
        display: block;
    }

    .guide-directory-toggle small {
        color: var(--brand-dark);
        font-size: 0.61rem;
        font-weight: 850;
        letter-spacing: 0.1em;
        text-transform: uppercase;
    }

    .guide-directory-toggle strong {
        margin-top: 2px;
        font-size: 0.92rem;
    }

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

    .email-guide-sidebar {
        position: fixed;
        top: calc(var(--header-height) + 12px);
        right: 18px;
        left: 18px;
        z-index: 950;
        max-height: calc(100vh - var(--header-height) - 24px);
        opacity: 0;
        pointer-events: none;
        transform: translateY(-14px) scale(0.985);
        transition: opacity 180ms ease, transform 180ms ease, visibility 0s linear 180ms;
        visibility: hidden;
    }

    .email-guide-sidebar.open {
        opacity: 1;
        pointer-events: auto;
        transform: translateY(0) scale(1);
        transition-delay: 0s;
        visibility: visible;
    }

    .guide-header {
        grid-template-columns: 1fr;
    }

    .guide-meta {
        min-width: 0;
        grid-template-columns: auto 1fr;
        justify-items: start;
        align-items: center;
    }

    .guide-meta strong {
        text-align: left;
    }
}

@media (max-width: 720px) {
    .email-hero {
        padding-top: 62px;
    }

    .email-hero-grid {
        gap: 46px;
    }

    .email-hero h1 {
        font-size: clamp(2.65rem, 13vw, 4rem);
        letter-spacing: -0.055em;
    }

    .mail-console {
        min-height: 0;
        padding: 20px;
        border-radius: 18px;
    }

    .mail-console-toolbar > span:nth-child(2) {
        display: none;
    }

    .mail-setting {
        grid-template-columns: auto 1fr;
    }

    .mail-setting > span:last-child {
        display: none;
    }

    .setup-foundation-grid,
    .guide-picker-heading,
    .library-heading {
        grid-template-columns: 1fr;
    }

    .guide-picker-heading,
    .library-heading {
        gap: 18px;
    }

    .setup-foundation-grid {
        gap: 13px;
    }

    .foundation-card {
        min-height: 0;
        padding: 25px;
        border-radius: 15px;
    }

    .foundation-checklist li {
        align-items: flex-start;
        flex-direction: column;
        gap: 2px;
    }

    .foundation-checklist strong {
        text-align: left;
    }

    .guide-picker-grid {
        grid-template-columns: 1fr;
    }

    .guide-picker-card {
        min-height: 185px;
    }

    .email-library {
        padding-top: 76px;
    }

    .email-guide {
        padding: 22px;
        border-radius: 15px;
    }

    .guide-header {
        gap: 22px;
        padding-bottom: 24px;
    }

    .guide-notice,
    .support-warning,
    .legacy-banner,
    .settings-caution {
        grid-template-columns: 1fr;
        gap: 6px;
    }

    .setup-prerequisites > summary,
    .legacy-archive > summary {
        align-items: flex-start;
    }

    .details-hint {
        display: none;
    }

    .guide-step {
        padding: 21px 18px;
    }

    .screenshot-button {
        padding: 9px;
    }

    .current-checklist ol {
        grid-template-columns: 1fr;
    }

    .legacy-archive-body {
        padding-inline: 18px;
    }

    .dialog-toolbar {
        padding: 13px 14px;
    }

    .dialog-canvas {
        padding: 10px;
    }

    .return-to-top {
        right: 14px;
        bottom: 14px;
    }
}

@media (max-width: 480px) {
    .mail-account-row strong {
        font-size: 0.8rem;
    }

    .email-guide {
        margin-inline: -2px;
    }

    .guide-header h2 {
        font-size: 2rem;
    }

    .setup-prerequisites > summary,
    .legacy-archive > summary {
        padding-inline: 15px;
    }

    .prerequisites-body {
        padding-inline: 15px;
    }
}

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

    .guide-picker-card,
    .screenshot-button,
    .subcategory,
    .email-guide-sidebar,
    .return-to-top {
        transition: none;
    }
}