/* メールJP.com ガイドページ 共通スタイル */
:root {
    --bg-gray: #f6f7f9;
    --border: #e5e7eb;
    --text-main: #111827;
    --text-muted: #6b7280;
    --text-sub: #374151;
    --blue-btn: #2563eb;
    --blue-hover: #1d4ed8;
    --blue-light: rgba(37, 99, 235, 0.08);
    --green: #16a34a;
    --green-light: #f0fdf4;
    --green-border: #bbf7d0;
    --orange: #d97706;
    --orange-light: #fffbeb;
    --orange-border: #fde68a;
    --surface: #ffffff;
    --radius-sm: 8px;
    --radius-md: 12px;
    --radius-lg: 14px;
    --shadow-card: 0 1px 3px rgba(0,0,0,0.06), 0 1px 2px rgba(0,0,0,0.04);
    --shadow-hover: 0 4px 12px rgba(0,0,0,0.08), 0 2px 4px rgba(0,0,0,0.04);
    --transition: 0.2s cubic-bezier(0.4, 0, 0.2, 1);
    --font: -apple-system, BlinkMacSystemFont, 'Segoe UI', Roboto, 'Hiragino Sans', 'Noto Sans JP', sans-serif;
}

* { margin: 0; padding: 0; box-sizing: border-box; }

body {
    font-family: var(--font);
    background: var(--bg-gray);
    color: var(--text-main);
    line-height: 1.75;
    font-size: 14px;
    -webkit-font-smoothing: antialiased;
}

/* ===== Header ===== */
.page-header {
    background: var(--surface);
    border-bottom: 1px solid var(--border);
    padding: 28px 24px 20px;
}

.header-inner {
    max-width: 780px;
    margin: 0 auto;
}

.brand-link {
    display: inline-block;
    font-size: 13px;
    color: var(--text-muted);
    text-decoration: none;
    margin-bottom: 10px;
    transition: color var(--transition);
}

.brand-link:hover { color: var(--blue-btn); }

.brand-link::before { content: "← "; }

.page-title {
    font-size: 22px;
    font-weight: 700;
    color: var(--text-main);
    letter-spacing: -0.01em;
    line-height: 1.35;
}

.page-title-sub {
    font-size: 13px;
    color: var(--text-muted);
    margin-top: 5px;
}

/* ===== Breadcrumb ===== */
.breadcrumb {
    font-size: 12px;
    color: var(--text-muted);
    margin-bottom: 6px;
}
.breadcrumb a { color: var(--text-muted); text-decoration: none; }
.breadcrumb a:hover { color: var(--blue-btn); }
.breadcrumb span { margin: 0 5px; }

/* ===== Main Layout ===== */
.page-body {
    max-width: 780px;
    margin: 0 auto;
    padding: 32px 20px 64px;
}

/* ===== Notice Boxes ===== */
.notice-box {
    border-radius: var(--radius-md);
    padding: 16px 20px;
    margin-bottom: 28px;
    font-size: 13px;
    line-height: 1.7;
}

.notice-box.mobile-tip {
    background: var(--green-light);
    border: 1px solid var(--green-border);
    color: #14532d;
}

.notice-box.info {
    background: var(--blue-light);
    border: 1px solid rgba(37, 99, 235, 0.2);
    color: #1e3a5f;
}

.notice-box.warning {
    background: var(--orange-light);
    border: 1px solid var(--orange-border);
    color: #78350f;
}

.notice-box-title {
    font-weight: 700;
    font-size: 13px;
    margin-bottom: 6px;
    display: flex;
    align-items: center;
    gap: 6px;
}

/* ===== Section ===== */
.guide-section {
    background: var(--surface);
    border: 1px solid var(--border);
    border-radius: var(--radius-lg);
    padding: 28px 28px 24px;
    margin-bottom: 20px;
    box-shadow: var(--shadow-card);
}

.section-heading {
    font-size: 17px;
    font-weight: 700;
    color: var(--text-main);
    margin-bottom: 18px;
    padding-bottom: 14px;
    border-bottom: 2px solid var(--border);
    display: flex;
    align-items: center;
    gap: 10px;
}

.section-heading .section-num {
    display: inline-flex;
    align-items: center;
    justify-content: center;
    width: 28px;
    height: 28px;
    background: var(--blue-btn);
    color: #fff;
    border-radius: 50%;
    font-size: 13px;
    font-weight: 700;
    flex-shrink: 0;
}

/* ===== Steps ===== */
.step-list {
    display: flex;
    flex-direction: column;
    gap: 20px;
}

.step {
    display: grid;
    grid-template-columns: 36px 1fr;
    gap: 0 14px;
    align-items: start;
}

.step-num {
    display: flex;
    align-items: center;
    justify-content: center;
    width: 32px;
    height: 32px;
    background: #f3f4f6;
    border: 2px solid var(--border);
    border-radius: 50%;
    font-size: 13px;
    font-weight: 700;
    color: var(--text-sub);
    flex-shrink: 0;
    margin-top: 1px;
}

.step-content {}

.step-title {
    font-size: 14px;
    font-weight: 700;
    color: var(--text-main);
    margin-bottom: 6px;
    line-height: 1.5;
}

.step-body {
    font-size: 13px;
    color: var(--text-sub);
    line-height: 1.75;
}

.step-body p { margin-bottom: 6px; }
.step-body p:last-child { margin-bottom: 0; }

.step-body ul, .step-body ol {
    padding-left: 18px;
    margin: 6px 0;
}

.step-body li { margin-bottom: 3px; }

/* ===== Image Placeholder ===== */
.guide-img {
    margin: 12px 0 4px;
    background: #f9fafb;
    border: 1.5px dashed #d1d5db;
    border-radius: var(--radius-sm);
    min-height: 140px;
    display: flex;
    align-items: center;
    justify-content: center;
    font-size: 12px;
    color: #9ca3af;
    font-weight: 500;
    letter-spacing: 0.02em;
    overflow: hidden;
    position: relative;
}

.guide-img img {
    width: 100%;
    height: auto;
    display: block;
    border-radius: calc(var(--radius-sm) - 2px);
}

.guide-img.mobile-screenshot {
    max-width: 320px;
}

/* ===== Inline Code / UI Label ===== */
.ui-label {
    display: inline-block;
    background: #f3f4f6;
    border: 1px solid #e5e7eb;
    border-radius: 4px;
    padding: 0 6px;
    font-size: 12px;
    font-weight: 600;
    color: var(--text-sub);
    font-family: inherit;
    white-space: nowrap;
}

code {
    background: #f3f4f6;
    padding: 1px 5px;
    border-radius: 4px;
    font-size: 12px;
    font-family: 'SFMono-Regular', Consolas, 'Liberation Mono', Menlo, monospace;
    color: var(--text-sub);
}

/* ===== CSS-Only Tab System ===== */
.tab-system {
    display: -webkit-flex;
    display: flex;
    -webkit-flex-wrap: wrap;
    flex-wrap: wrap;
}

.tab-radio {
    position: absolute;
    width: 1px;
    height: 1px;
    opacity: 0;
    overflow: hidden;
    clip: rect(0, 0, 0, 0);
}

.tab-system .platform-tab {
    display: -webkit-inline-flex;
    display: inline-flex;
    -webkit-align-items: center;
    align-items: center;
    padding: 10px 18px;
    min-height: 44px;
    font-size: 13px;
    font-weight: 600;
    color: var(--text-muted);
    cursor: pointer;
    background: none;
    border: none;
    font-family: var(--font);
    border-bottom: 2px solid transparent;
    margin-bottom: -2px;
    position: relative;
    z-index: 2;
    -webkit-user-select: none;
    user-select: none;
    touch-action: manipulation;
}

.tab-system .platform-tab:hover {
    color: var(--text-main);
}

.tab-border {
    width: 100%;
    height: 0;
    border-bottom: 2px solid var(--border);
    margin-bottom: 20px;
    -webkit-order: 1;
    order: 1;
}

.tab-system .platform-panel {
    display: none;
    width: 100%;
    -webkit-order: 2;
    order: 2;
}

/* Active tab styling — pure CSS, no JS needed */
.tab-radio:checked + .platform-tab {
    color: var(--blue-btn);
    border-bottom-color: var(--blue-btn);
}

/* Show active panel — pure CSS */
#tab-safari:checked ~ .panel-safari { display: block; }
#tab-chrome:checked ~ .panel-chrome { display: block; }

/* ===== Accordion (FAQ) — CSS-only ===== */
.sub-section {
    background: #f9fafb;
    border: 1px solid var(--border);
    border-radius: var(--radius-sm);
    margin-top: 10px;
    overflow: hidden;
}

.sub-toggle {
    position: absolute;
    width: 1px;
    height: 1px;
    opacity: 0;
    overflow: hidden;
    clip: rect(0, 0, 0, 0);
}

.sub-section-title {
    width: 100%;
    display: flex;
    align-items: center;
    justify-content: space-between;
    padding: 10px 14px;
    font-size: 13px;
    font-weight: 600;
    color: var(--text-sub);
    background: none;
    border: none;
    cursor: pointer;
    font-family: var(--font);
    text-align: left;
}

.sub-section-arrow {
    font-size: 10px;
    color: var(--text-muted);
    transition: transform var(--transition);
}

.sub-toggle:checked ~ .sub-section-title .sub-section-arrow {
    transform: rotate(180deg);
}

.sub-section-body {
    display: none;
    padding: 0 14px 14px;
    font-size: 13px;
    color: var(--text-sub);
    line-height: 1.75;
}

.sub-toggle:checked ~ .sub-section-body {
    display: block;
}

/* ===== Tag ===== */
.tag {
    display: inline-block;
    padding: 2px 8px;
    border-radius: 999px;
    font-size: 11px;
    font-weight: 600;
    margin-left: 6px;
}

.tag.mobile { background: #dbeafe; color: #1d4ed8; }
.tag.pc { background: #f3f4f6; color: #4b5563; }

/* ===== CTA Box ===== */
.cta-box {
    background: var(--surface);
    border: 1px solid var(--border);
    border-radius: var(--radius-lg);
    padding: 24px 28px;
    text-align: center;
    margin-top: 32px;
    box-shadow: var(--shadow-card);
}

.cta-box p {
    font-size: 14px;
    color: var(--text-muted);
    margin-bottom: 14px;
    line-height: 1.6;
}

.cta-links {
    display: flex;
    justify-content: center;
    gap: 12px;
    flex-wrap: wrap;
}

.cta-link {
    display: inline-block;
    padding: 9px 20px;
    border-radius: var(--radius-sm);
    font-size: 13px;
    font-weight: 600;
    text-decoration: none;
    transition: all var(--transition);
}

.cta-link.primary {
    background: var(--blue-btn);
    color: #fff;
    box-shadow: 0 2px 8px rgba(37,99,235,0.25);
}

.cta-link.primary:hover {
    background: var(--blue-hover);
    transform: translateY(-1px);
    box-shadow: 0 4px 12px rgba(37,99,235,0.35);
}

.cta-link.secondary {
    border: 1px solid var(--border);
    color: var(--text-sub);
    background: var(--surface);
}

.cta-link.secondary:hover {
    border-color: var(--blue-btn);
    color: var(--blue-btn);
}

/* ===== Footer ===== */
.page-footer {
    background: var(--surface);
    border-top: 1px solid var(--border);
    padding: 24px 20px;
    text-align: center;
}

.footer-links {
    display: flex;
    justify-content: center;
    gap: 20px;
    flex-wrap: wrap;
    margin-bottom: 10px;
}

.footer-links a {
    font-size: 12px;
    color: var(--text-muted);
    text-decoration: none;
    transition: color var(--transition);
}

.footer-links a:hover { color: var(--blue-btn); }

.footer-copy {
    font-size: 11px;
    color: #9ca3af;
}

/* ===== Responsive ===== */
@media (max-width: 640px) {
    .page-header { padding: 20px 16px 16px; }
    .page-title { font-size: 18px; }
    .page-body { padding: 20px 12px 48px; }
    .guide-section { padding: 20px 16px 18px; }
    .section-heading { font-size: 15px; }
    .step { grid-template-columns: 30px 1fr; gap: 0 10px; }
    .step-num { width: 28px; height: 28px; font-size: 12px; }
    .step-title { font-size: 13px; }
    .cta-box { padding: 20px 16px; }
    .tab-system .platform-tab { padding: 7px 12px; font-size: 12px; }
}