/* ALT コラム / 管理画面 共通スタイル
   既存HPはインラインスタイル中心だが、コラムと管理画面は記事本文という
   「量が読めないコンテンツ」を扱うため、クラスベースで書く。
   デザイントークンは既存HP（--accent:#2563c9 系）とそろえている。 */

:root {
  --accent: #2563c9;
  --accent-dark: #1b4a99;
  --accent-soft: rgba(37, 99, 201, 0.08);
  --ink: #14181f;
  --muted: #5a6473;
  --line: #e7ebf1;
  --tint: #f4f7fb;
  --shell: #0a0d14;
  --danger: #c0392b;
  --ok: #12805c;
  --radius: 16px;
  --sans: -apple-system, BlinkMacSystemFont, 'Hiragino Kaku Gothic ProN',
    'Hiragino Sans', 'Yu Gothic', 'Meiryo', sans-serif;
  --latin: 'Helvetica Neue', Arial, sans-serif;
}

* { box-sizing: border-box; }

html {
  background: #fff;
  scroll-behavior: smooth;
  scroll-padding-top: 96px;
}

body {
  margin: 0;
  background: #fff;
  color: var(--ink);
  font-family: var(--sans);
  -webkit-font-smoothing: antialiased;
  text-rendering: optimizeLegibility;
}

a { color: inherit; text-decoration: none; }
img { max-width: 100%; }
::selection { background: rgba(37, 99, 201, 0.16); }

@keyframes altUp {
  from { opacity: 0; transform: translateY(24px); }
  to { opacity: 1; transform: none; }
}

.alt-inner { max-width: 1180px; margin: 0 auto; }
.alt-narrow { max-width: 820px; margin: 0 auto; }

/* ============ HEADER ============ */

.alt-header {
  position: sticky;
  top: 0;
  z-index: 50;
  background: rgba(255, 255, 255, 0.9);
  backdrop-filter: saturate(180%) blur(14px);
  -webkit-backdrop-filter: saturate(180%) blur(14px);
  border-bottom: 1px solid var(--line);
}

.alt-header > div {
  max-width: 1180px;
  margin: 0 auto;
  padding: 0 48px;
  height: 72px;
  display: flex;
  align-items: center;
  justify-content: space-between;
}

.alt-header img { height: 30px; width: auto; display: block; }

.alt-nav { display: flex; align-items: center; gap: 34px; }

.alt-nav a {
  font-size: 14px;
  font-weight: 500;
  color: var(--muted);
  transition: color 0.2s;
}

.alt-nav a:hover { color: var(--ink); }
.alt-nav a.is-current { font-weight: 700; color: var(--ink); }

.alt-nav .alt-nav-cta {
  display: inline-flex;
  align-items: center;
  gap: 8px;
  font-weight: 700;
  color: #fff;
  background: var(--accent);
  padding: 11px 20px;
  border-radius: 999px;
  transition: transform 0.2s;
}

.alt-nav .alt-nav-cta:hover { color: #fff; transform: translateY(-1px); }

/* ============ HERO ============ */

.alt-hero {
  position: relative;
  overflow: hidden;
  color: #fff;
  padding: 96px 48px 84px;
  background: var(--shell);
}

.alt-hero-bg {
  position: absolute;
  inset: 0;
  width: 100%;
  height: 100%;
  object-fit: cover;
  z-index: 0;
}

/* 記事タイトルは長さも背景も選べないので、**どの画像でも白文字が読める濃さ**にする。
   既存HPの下層ページより気持ち濃いのはそのため */
.alt-hero-veil {
  position: absolute;
  inset: 0;
  z-index: 1;
  background: linear-gradient(
    100deg,
    rgba(9, 13, 20, 0.92) 0%,
    rgba(9, 13, 20, 0.78) 46%,
    rgba(9, 13, 20, 0.58) 100%
  );
}

.alt-hero > .alt-inner { position: relative; z-index: 2; }

.alt-crumb {
  display: flex;
  align-items: center;
  gap: 10px;
  flex-wrap: wrap;
  font-family: var(--latin);
  font-size: 12px;
  color: rgba(255, 255, 255, 0.6);
  margin-bottom: 20px;
  animation: altUp 0.6s ease both;
}

.alt-crumb a { transition: color 0.2s; }
.alt-crumb a:hover { color: #fff; }
.alt-crumb .is-current {
  color: #fff;
  max-width: 46ch;
  overflow: hidden;
  text-overflow: ellipsis;
  white-space: nowrap;
}

.alt-eyebrow {
  font-family: var(--latin);
  font-size: 12px;
  font-weight: 700;
  letter-spacing: 0.2em;
  color: #8fb2f0;
  margin-bottom: 14px;
  animation: altUp 0.6s ease both;
  animation-delay: 0.05s;
}

.alt-hero h1 {
  margin: 0;
  font-size: clamp(32px, 4.6vw, 56px);
  font-weight: 900;
  line-height: 1.2;
  animation: altUp 0.7s ease both;
  animation-delay: 0.1s;
}

.alt-hero-lead {
  margin: 24px 0 0;
  max-width: 620px;
  font-size: 16px;
  line-height: 2;
  color: rgba(255, 255, 255, 0.8);
  animation: altUp 0.7s ease both;
  animation-delay: 0.18s;
}

.alt-hero-meta {
  display: flex;
  align-items: center;
  gap: 14px;
  flex-wrap: wrap;
  margin-top: 26px;
  animation: altUp 0.7s ease both;
  animation-delay: 0.24s;
}

.alt-hero-date {
  font-family: var(--latin);
  font-size: 13px;
  color: rgba(255, 255, 255, 0.65);
}

.alt-hero-credit {
  margin: 28px 0 0;
  font-family: var(--latin);
  font-size: 11px;
  color: rgba(255, 255, 255, 0.42);
}

.alt-hero-credit a {
  color: rgba(255, 255, 255, 0.62);
  text-decoration: underline;
  text-underline-offset: 2px;
}

.alt-hero-credit a:hover { color: #fff; }

/* ============ TAG ============ */

.alt-tag {
  display: inline-block;
  font-size: 12px;
  font-weight: 700;
  line-height: 1;
  padding: 7px 12px;
  border-radius: 999px;
  color: var(--accent);
  background: var(--accent-soft);
  white-space: nowrap;
}

.alt-tag.on-dark {
  color: #cfe0ff;
  background: rgba(143, 178, 240, 0.18);
  border: 1px solid rgba(143, 178, 240, 0.3);
}

/* ============ SECTION ============ */

.alt-section { padding: 88px 48px; }
.alt-section.is-tint { background: var(--tint); }

.alt-section-head { margin-bottom: 40px; }

.alt-section-head h2 {
  margin: 0;
  font-size: clamp(22px, 2.6vw, 30px);
  font-weight: 900;
  line-height: 1.4;
}

.alt-section-head p {
  margin: 12px 0 0;
  font-size: 15px;
  line-height: 1.9;
  color: var(--muted);
}

/* ============ COLUMN LIST ============ */

.alt-card-grid {
  display: grid;
  grid-template-columns: repeat(3, 1fr);
  gap: 28px;
  list-style: none;
  margin: 0;
  padding: 0;
}

.alt-card {
  display: flex;
  flex-direction: column;
  height: 100%;
  background: #fff;
  border: 1px solid var(--line);
  border-radius: var(--radius);
  overflow: hidden;
  transition: transform 0.25s cubic-bezier(0.22, 0.61, 0.36, 1),
    box-shadow 0.25s ease, border-color 0.25s ease;
}

.alt-card:hover {
  transform: translateY(-4px);
  border-color: rgba(37, 99, 201, 0.28);
  box-shadow: 0 22px 44px -26px rgba(20, 24, 31, 0.45);
}

.alt-card-thumb {
  position: relative;
  aspect-ratio: 16 / 9;
  background: linear-gradient(135deg, #17233a 0%, #24406f 55%, #2563c9 100%);
  overflow: hidden;
}

.alt-card-thumb img {
  width: 100%;
  height: 100%;
  object-fit: cover;
  display: block;
  transition: transform 0.5s cubic-bezier(0.22, 0.61, 0.36, 1);
}

.alt-card:hover .alt-card-thumb img { transform: scale(1.05); }

.alt-card-thumb-mark {
  position: absolute;
  inset: 0;
  display: flex;
  align-items: center;
  justify-content: center;
  font-family: var(--latin);
  font-size: 13px;
  font-weight: 700;
  letter-spacing: 0.22em;
  color: rgba(255, 255, 255, 0.5);
}

.alt-card-body {
  display: flex;
  flex-direction: column;
  flex: 1;
  padding: 22px 24px 24px;
}

.alt-card-meta {
  display: flex;
  align-items: center;
  gap: 12px;
  flex-wrap: wrap;
  margin-bottom: 14px;
}

.alt-card-date {
  font-family: var(--latin);
  font-size: 12px;
  color: var(--muted);
}

.alt-card h2,
.alt-card h3 {
  margin: 0;
  font-size: 17px;
  font-weight: 700;
  line-height: 1.6;
  color: var(--ink);
  display: -webkit-box;
  -webkit-line-clamp: 3;
  -webkit-box-orient: vertical;
  overflow: hidden;
}

.alt-card-desc {
  margin: 12px 0 0;
  font-size: 13.5px;
  line-height: 1.9;
  color: var(--muted);
  display: -webkit-box;
  -webkit-line-clamp: 3;
  -webkit-box-orient: vertical;
  overflow: hidden;
}

.alt-card-more {
  display: inline-flex;
  align-items: center;
  gap: 7px;
  margin-top: auto;
  padding-top: 20px;
  font-size: 13px;
  font-weight: 700;
  color: var(--accent);
}

.alt-card-more svg { transition: transform 0.25s ease; }
.alt-card:hover .alt-card-more svg { transform: translateX(4px); }

/* ============ EMPTY ============ */

.alt-empty {
  border: 1px dashed var(--line);
  border-radius: var(--radius);
  padding: 72px 32px;
  text-align: center;
  background: #fff;
}

.alt-empty h2 {
  margin: 0 0 10px;
  font-size: 18px;
  font-weight: 700;
}

.alt-empty p {
  margin: 0;
  font-size: 14px;
  line-height: 1.9;
  color: var(--muted);
}

/* ============ PAGINATION ============ */

.alt-pager {
  display: flex;
  align-items: center;
  justify-content: center;
  gap: 10px;
  flex-wrap: wrap;
  margin-top: 56px;
}

.alt-pager a,
.alt-pager span {
  min-width: 42px;
  height: 42px;
  padding: 0 14px;
  display: inline-flex;
  align-items: center;
  justify-content: center;
  border: 1px solid var(--line);
  border-radius: 999px;
  font-family: var(--latin);
  font-size: 13px;
  font-weight: 600;
  color: var(--muted);
  background: #fff;
  transition: all 0.2s;
}

.alt-pager a:hover { border-color: var(--accent); color: var(--accent); }

.alt-pager .is-active {
  background: var(--accent);
  border-color: var(--accent);
  color: #fff;
}

.alt-pager .is-disabled { opacity: 0.4; }

/* ============ ARTICLE ============ */

.alt-article-wrap {
  display: grid;
  grid-template-columns: minmax(0, 1fr) 260px;
  gap: 56px;
  align-items: start;
}

.alt-article {
  font-size: 16px;
  line-height: 2.05;
  color: #23282f;
  min-width: 0;
}

.alt-article > *:first-child { margin-top: 0; }

.alt-article h2 {
  margin: 64px 0 22px;
  padding: 0 0 14px 16px;
  border-left: 4px solid var(--accent);
  border-bottom: 1px solid var(--line);
  font-size: 24px;
  font-weight: 900;
  line-height: 1.5;
  color: var(--ink);
  scroll-margin-top: 96px;
}

.alt-article h3 {
  margin: 44px 0 16px;
  font-size: 19px;
  font-weight: 700;
  line-height: 1.6;
  color: var(--ink);
  scroll-margin-top: 96px;
}

.alt-article h4 {
  margin: 32px 0 12px;
  font-size: 16px;
  font-weight: 700;
  color: var(--ink);
}

.alt-article p { margin: 0 0 26px; }

.alt-article a {
  color: var(--accent);
  text-decoration: underline;
  text-underline-offset: 3px;
  text-decoration-thickness: 1px;
}

.alt-article a:hover { color: var(--accent-dark); }

.alt-article ul,
.alt-article ol { margin: 0 0 28px; padding-left: 1.4em; }
.alt-article li { margin-bottom: 10px; }
.alt-article li::marker { color: var(--accent); }

.alt-article blockquote {
  margin: 0 0 28px;
  padding: 20px 24px;
  background: var(--tint);
  border-left: 3px solid var(--accent);
  border-radius: 0 10px 10px 0;
  color: var(--muted);
  font-size: 15px;
}

.alt-article blockquote p:last-child { margin-bottom: 0; }

.alt-article img {
  display: block;
  width: 100%;
  height: auto;
  margin: 8px 0 32px;
  border-radius: 12px;
  border: 1px solid var(--line);
}

.alt-article hr {
  margin: 48px 0;
  border: 0;
  border-top: 1px solid var(--line);
}

.alt-article code {
  font-family: ui-monospace, SFMono-Regular, Menlo, Consolas, monospace;
  font-size: 0.88em;
  padding: 0.15em 0.45em;
  background: var(--tint);
  border: 1px solid var(--line);
  border-radius: 5px;
}

.alt-article pre {
  margin: 0 0 28px;
  padding: 20px;
  background: #0f1420;
  border-radius: 12px;
  overflow-x: auto;
  font-size: 13.5px;
  line-height: 1.75;
}

.alt-article pre code {
  padding: 0;
  background: none;
  border: 0;
  color: #e6ebf5;
}

.alt-table-scroll { overflow-x: auto; margin: 0 0 28px; }

.alt-article table {
  width: 100%;
  border-collapse: collapse;
  font-size: 14.5px;
}

.alt-article th,
.alt-article td {
  padding: 13px 16px;
  border: 1px solid var(--line);
  text-align: left;
  vertical-align: top;
}

.alt-article th {
  background: var(--tint);
  font-weight: 700;
  white-space: nowrap;
}

/* ============ TOC ============ */

.alt-toc {
  position: sticky;
  top: 96px;
  padding: 24px;
  background: var(--tint);
  border-radius: var(--radius);
  border: 1px solid var(--line);
}

.alt-toc-title {
  font-family: var(--latin);
  font-size: 11px;
  font-weight: 700;
  letter-spacing: 0.18em;
  color: var(--muted);
  margin-bottom: 14px;
}

.alt-toc ol {
  margin: 0;
  padding: 0;
  list-style: none;
  counter-reset: toc;
}

.alt-toc li { counter-increment: toc; margin-bottom: 12px; }
.alt-toc li:last-child { margin-bottom: 0; }

.alt-toc a {
  display: flex;
  gap: 9px;
  font-size: 13px;
  line-height: 1.65;
  color: var(--muted);
  transition: color 0.2s;
}

.alt-toc a::before {
  content: counter(toc, decimal-leading-zero);
  font-family: var(--latin);
  font-size: 11px;
  font-weight: 700;
  color: var(--accent);
  padding-top: 2px;
}

.alt-toc a:hover { color: var(--ink); }

/* ============ AUTHOR ============ */

.alt-author {
  display: flex;
  gap: 18px;
  align-items: center;
  margin-top: 64px;
  padding: 24px;
  border: 1px solid var(--line);
  border-radius: var(--radius);
  background: #fff;
}

.alt-author-mark {
  flex: none;
  width: 54px;
  height: 54px;
  border-radius: 50%;
  background: var(--tint);
  border: 1px solid var(--line);
  display: flex;
  align-items: center;
  justify-content: center;
}

.alt-author-mark img { width: 30px; height: auto; }

.alt-author-name { font-size: 14px; font-weight: 700; }

.alt-author-desc {
  margin: 6px 0 0;
  font-size: 12.5px;
  line-height: 1.8;
  color: var(--muted);
}

/* ============ CTA ============ */

.alt-cta {
  position: relative;
  overflow: hidden;
  margin-top: 72px;
  padding: 56px 48px;
  border-radius: 22px;
  background: linear-gradient(120deg, #101828 0%, #1b3560 55%, #2563c9 100%);
  color: #fff;
  text-align: center;
}

.alt-cta-eyebrow {
  font-family: var(--latin);
  font-size: 11px;
  font-weight: 700;
  letter-spacing: 0.2em;
  color: #8fb2f0;
  margin: 0 0 14px;
}

.alt-cta h2 {
  margin: 0;
  font-size: clamp(20px, 2.6vw, 28px);
  font-weight: 900;
  line-height: 1.5;
}

.alt-cta p {
  margin: 16px auto 28px;
  max-width: 560px;
  font-size: 14.5px;
  line-height: 1.95;
  color: rgba(255, 255, 255, 0.78);
}

.alt-cta-btn {
  display: inline-flex;
  align-items: center;
  gap: 10px;
  padding: 15px 32px;
  border-radius: 999px;
  background: #fff;
  color: #14181f;
  font-size: 14px;
  font-weight: 700;
  transition: transform 0.2s, box-shadow 0.2s;
}

.alt-cta-btn:hover {
  transform: translateY(-2px);
  box-shadow: 0 18px 34px -18px rgba(0, 0, 0, 0.6);
}

/* ============ RELATED ============ */

.alt-related { margin-top: 84px; }

.alt-related-title {
  font-family: var(--latin);
  font-size: 11px;
  font-weight: 700;
  letter-spacing: 0.18em;
  color: var(--muted);
  margin-bottom: 22px;
}

/* ============ FOOTER ============ */

.alt-footer {
  background-color: #0a0d14;
  color: #fff;
  padding: 60px 48px 34px;
  background-image: linear-gradient(rgba(9, 12, 19, 0.86), rgba(9, 12, 19, 0.93)),
    url('/uploads/placidplace-frequency-wave-7776034.jpg');
  background-size: cover;
  background-position: center;
}

.alt-footer-top {
  display: flex;
  justify-content: space-between;
  gap: 40px;
  flex-wrap: wrap;
  padding-bottom: 40px;
  border-bottom: 1px solid rgba(255, 255, 255, 0.1);
}

.alt-footer-logo { height: 34px; width: auto; display: block; }
.alt-footer-name { margin-top: 16px; font-size: 14px; font-weight: 700; }

.alt-footer-addr {
  margin: 18px 0 0;
  font-size: 13px;
  line-height: 1.8;
  color: #8a93a6;
}

.alt-footer-nav { display: flex; gap: 64px; flex-wrap: wrap; }
.alt-footer-col { display: flex; flex-direction: column; gap: 13px; }

.alt-footer-col span {
  font-family: var(--latin);
  font-size: 11px;
  font-weight: 700;
  letter-spacing: 0.18em;
  color: #6b7488;
}

.alt-footer-col a {
  font-size: 14px;
  color: #c4cbd8;
  transition: color 0.2s;
}

.alt-footer a:hover { color: #fff; }

.alt-footer-bottom {
  display: flex;
  justify-content: space-between;
  align-items: center;
  gap: 16px;
  flex-wrap: wrap;
  padding-top: 24px;
}

.alt-footer-bottom small {
  font-family: var(--latin);
  font-size: 12px;
  color: #6b7488;
}

.alt-footer-bottom a { font-size: 12px; color: #c4cbd8; transition: color 0.2s; }

/* ============ ADMIN ============ */

.alt-admin { background: #f6f8fb; min-height: 100vh; }

.alt-admin-bar {
  position: sticky;
  top: 0;
  z-index: 40;
  background: #0a0d14;
  color: #fff;
}

.alt-admin-bar > div {
  max-width: 1120px;
  margin: 0 auto;
  padding: 0 32px;
  height: 62px;
  display: flex;
  align-items: center;
  justify-content: space-between;
  gap: 20px;
}

.alt-admin-brand { display: flex; align-items: center; gap: 14px; }
.alt-admin-brand img { height: 24px; width: auto; }

.alt-admin-brand span {
  font-family: var(--latin);
  font-size: 11px;
  font-weight: 700;
  letter-spacing: 0.16em;
  color: #8fb2f0;
  padding: 5px 10px;
  border: 1px solid rgba(143, 178, 240, 0.35);
  border-radius: 999px;
}

.alt-admin-bar nav { display: flex; align-items: center; gap: 22px; }

.alt-admin-bar nav a {
  font-size: 13px;
  color: #c4cbd8;
  transition: color 0.2s;
}

.alt-admin-bar nav a:hover { color: #fff; }

.alt-admin-main { max-width: 1120px; margin: 0 auto; padding: 40px 32px 88px; }

.alt-admin-head {
  display: flex;
  align-items: flex-end;
  justify-content: space-between;
  gap: 20px;
  flex-wrap: wrap;
  margin-bottom: 28px;
}

.alt-admin-head h1 { margin: 0; font-size: 24px; font-weight: 900; }

.alt-admin-head p {
  margin: 8px 0 0;
  font-size: 13px;
  color: var(--muted);
}

.alt-stat-grid {
  display: grid;
  grid-template-columns: repeat(4, 1fr);
  gap: 16px;
  margin-bottom: 32px;
}

.alt-stat {
  background: #fff;
  border: 1px solid var(--line);
  border-radius: 14px;
  padding: 20px 22px;
}

.alt-stat dt {
  font-size: 12px;
  font-weight: 600;
  color: var(--muted);
  margin: 0 0 10px;
}

.alt-stat dd {
  margin: 0;
  font-family: var(--latin);
  font-size: 30px;
  font-weight: 700;
  line-height: 1;
  color: var(--ink);
}

.alt-stat dd small {
  font-size: 12px;
  font-weight: 600;
  color: var(--muted);
  margin-left: 5px;
}

.alt-panel {
  background: #fff;
  border: 1px solid var(--line);
  border-radius: var(--radius);
  overflow: hidden;
  margin-bottom: 28px;
}

.alt-panel-head {
  display: flex;
  align-items: center;
  justify-content: space-between;
  gap: 16px;
  flex-wrap: wrap;
  padding: 18px 24px;
  border-bottom: 1px solid var(--line);
  background: #fbfcfe;
}

.alt-panel-head h2 { margin: 0; font-size: 14px; font-weight: 700; }

.alt-panel-head p {
  margin: 5px 0 0;
  font-size: 12px;
  color: var(--muted);
}

.alt-panel-body { padding: 24px; }

.alt-table { width: 100%; border-collapse: collapse; font-size: 13.5px; }

.alt-table th {
  text-align: left;
  padding: 12px 20px;
  background: #fbfcfe;
  border-bottom: 1px solid var(--line);
  font-size: 11px;
  font-weight: 700;
  letter-spacing: 0.06em;
  color: var(--muted);
  white-space: nowrap;
}

.alt-table td {
  padding: 15px 20px;
  border-bottom: 1px solid #f1f4f8;
  vertical-align: middle;
}

.alt-table tr:last-child td { border-bottom: 0; }
.alt-table tbody tr:hover { background: #fafbfd; }

.alt-table-title {
  font-weight: 700;
  color: var(--ink);
  display: block;
  max-width: 420px;
  overflow: hidden;
  text-overflow: ellipsis;
  white-space: nowrap;
}

.alt-table-title:hover { color: var(--accent); }

.alt-table-slug {
  display: block;
  margin-top: 4px;
  font-family: var(--latin);
  font-size: 11.5px;
  color: var(--muted);
}

.alt-row-actions { display: flex; gap: 8px; justify-content: flex-end; }

.alt-badge {
  display: inline-block;
  font-size: 11px;
  font-weight: 700;
  padding: 5px 10px;
  border-radius: 999px;
  white-space: nowrap;
}

.alt-badge.is-published { color: var(--ok); background: rgba(18, 128, 92, 0.1); }
.alt-badge.is-draft { color: #8a6d1f; background: rgba(200, 160, 40, 0.14); }
.alt-badge.is-auto { color: var(--accent); background: var(--accent-soft); }
.alt-badge.is-manual { color: var(--muted); background: #eef1f6; }

/* ============ BUTTONS / FORMS ============ */

.alt-btn {
  display: inline-flex;
  align-items: center;
  justify-content: center;
  gap: 8px;
  padding: 11px 20px;
  border: 1px solid transparent;
  border-radius: 10px;
  font-family: inherit;
  font-size: 13px;
  font-weight: 700;
  line-height: 1;
  cursor: pointer;
  transition: all 0.2s;
  background: var(--accent);
  color: #fff;
}

.alt-btn:hover { background: var(--accent-dark); color: #fff; }

.alt-btn.is-ghost {
  background: #fff;
  color: var(--ink);
  border-color: var(--line);
}

.alt-btn.is-ghost:hover { background: var(--tint); color: var(--ink); border-color: #cfd8e4; }

.alt-btn.is-danger { background: #fff; color: var(--danger); border-color: rgba(192, 57, 43, 0.3); }
.alt-btn.is-danger:hover { background: rgba(192, 57, 43, 0.07); color: var(--danger); }

.alt-btn.is-sm { padding: 8px 14px; font-size: 12px; border-radius: 8px; }
.alt-btn.is-block { width: 100%; padding: 14px 20px; font-size: 14px; }

.alt-field { margin-bottom: 22px; }

.alt-field label {
  display: block;
  margin-bottom: 8px;
  font-size: 12.5px;
  font-weight: 700;
  color: var(--ink);
}

.alt-field label .req { color: var(--danger); margin-left: 4px; }

.alt-field .hint {
  margin: 7px 0 0;
  font-size: 11.5px;
  line-height: 1.7;
  color: var(--muted);
}

.alt-input,
.alt-select,
.alt-textarea {
  width: 100%;
  padding: 12px 14px;
  border: 1px solid var(--line);
  border-radius: 10px;
  background: #fff;
  font-family: inherit;
  font-size: 14px;
  line-height: 1.6;
  color: var(--ink);
  transition: border-color 0.2s, box-shadow 0.2s;
}

.alt-input:focus,
.alt-select:focus,
.alt-textarea:focus {
  outline: none;
  border-color: var(--accent);
  box-shadow: 0 0 0 3px rgba(37, 99, 201, 0.12);
}

.alt-textarea {
  min-height: 480px;
  resize: vertical;
  font-family: ui-monospace, SFMono-Regular, Menlo, Consolas, monospace;
  font-size: 13.5px;
  line-height: 1.85;
}

.alt-input.is-mono {
  font-family: ui-monospace, SFMono-Regular, Menlo, Consolas, monospace;
  font-size: 13px;
}

.alt-form-grid {
  display: grid;
  grid-template-columns: minmax(0, 1fr) 300px;
  gap: 32px;
  align-items: start;
}

.alt-form-side {
  position: sticky;
  top: 86px;
  background: #fff;
  border: 1px solid var(--line);
  border-radius: var(--radius);
  padding: 24px;
}

.alt-form-actions {
  display: flex;
  gap: 10px;
  flex-wrap: wrap;
  padding-top: 20px;
  margin-top: 4px;
  border-top: 1px solid var(--line);
}

/* ============ ALERT / CODE BLOCK ============ */

.alt-alert {
  padding: 14px 18px;
  border-radius: 10px;
  font-size: 13px;
  line-height: 1.75;
  margin-bottom: 22px;
}

.alt-alert.is-error {
  color: #8c281c;
  background: rgba(192, 57, 43, 0.08);
  border: 1px solid rgba(192, 57, 43, 0.22);
}

.alt-alert.is-ok {
  color: #0d5f45;
  background: rgba(18, 128, 92, 0.08);
  border: 1px solid rgba(18, 128, 92, 0.22);
}

.alt-alert.is-info {
  color: #24405f;
  background: var(--accent-soft);
  border: 1px solid rgba(37, 99, 201, 0.2);
}

.alt-code {
  display: block;
  padding: 14px 16px;
  background: #0f1420;
  color: #e6ebf5;
  border-radius: 10px;
  font-family: ui-monospace, SFMono-Regular, Menlo, Consolas, monospace;
  font-size: 12.5px;
  line-height: 1.8;
  overflow-x: auto;
  white-space: pre-wrap;
  word-break: break-all;
}

.alt-kv { margin: 0; font-size: 13px; }
.alt-kv dt { font-weight: 700; margin-bottom: 6px; }
.alt-kv dd { margin: 0 0 18px; color: var(--muted); line-height: 1.8; }
.alt-kv dd:last-child { margin-bottom: 0; }

/* ============ LOGIN ============ */

.alt-login {
  min-height: 100vh;
  display: flex;
  align-items: center;
  justify-content: center;
  padding: 40px 24px;
  background: #0a0d14;
  background-image: linear-gradient(rgba(9, 12, 19, 0.9), rgba(9, 12, 19, 0.95)),
    url('/uploads/placidplace-frequency-wave-7776034.jpg');
  background-size: cover;
  background-position: center;
}

.alt-login-card {
  width: 100%;
  max-width: 420px;
  background: #fff;
  border-radius: 20px;
  padding: 40px;
  box-shadow: 0 40px 80px -40px rgba(0, 0, 0, 0.7);
  animation: altUp 0.6s ease both;
}

.alt-login-card img { height: 28px; width: auto; margin-bottom: 26px; }

.alt-login-card h1 { margin: 0 0 8px; font-size: 20px; font-weight: 900; }

.alt-login-card > p {
  margin: 0 0 28px;
  font-size: 13px;
  line-height: 1.8;
  color: var(--muted);
}

.alt-login-back {
  display: block;
  margin-top: 24px;
  text-align: center;
  font-size: 12px;
  color: var(--muted);
}

.alt-login-back:hover { color: var(--ink); }

/* ============ RESPONSIVE ============ */

@media (max-width: 1024px) {
  .alt-article-wrap { grid-template-columns: minmax(0, 1fr); gap: 0; }
  .alt-toc { position: static; margin-bottom: 40px; }
  .alt-form-grid { grid-template-columns: minmax(0, 1fr); }
  .alt-form-side { position: static; }
  .alt-stat-grid { grid-template-columns: repeat(2, 1fr); }
}

@media (max-width: 900px) {
  .alt-card-grid { grid-template-columns: repeat(2, 1fr); }
}

@media (max-width: 768px) {
  .alt-header > div { padding: 0 20px; }
  .alt-hero { padding: 64px 20px 56px; }
  .alt-section { padding: 60px 20px; }
  .alt-footer { padding: 48px 22px 30px; }
  .alt-footer-nav { gap: 40px; }
  .alt-cta { padding: 40px 24px; margin-top: 56px; }
  .alt-admin-bar > div,
  .alt-admin-main { padding-left: 20px; padding-right: 20px; }
  .alt-article { font-size: 15.5px; }
  .alt-article h2 { font-size: 21px; margin-top: 48px; }
  .alt-table-scroll { -webkit-overflow-scrolling: touch; }
  .alt-panel-body { padding: 20px; }
}

@media (max-width: 600px) {
  .alt-card-grid { grid-template-columns: 1fr; }
  .alt-stat-grid { grid-template-columns: 1fr; }
  .alt-login-card { padding: 30px 24px; }
}

/* 動きを減らす設定の環境では、フェードインを最終状態で固定する。
   opacity:0 から始まる演出なので、**animation を単に止めると内容が消える**。
   none にして初期値（不透明）に戻す必要がある */
@media (prefers-reduced-motion: reduce) {
  *,
  *::before,
  *::after {
    animation: none !important;
    transition-duration: 0.01ms !important;
    scroll-behavior: auto !important;
  }
}