/* 広島AI導入支援（仮称） — モノクロ基調 / 明朝見出し / 細罫線 / 余白多め
   グラデーション・角丸・影・多色は使わない */

:root {
  --ink: #111111;
  --ink-sub: #555555;
  --ink-mute: #888888;
  --paper: #ffffff;
  --paper-alt: #f6f6f4;
  --rule: #d8d8d8;
  --rule-strong: #111111;
  --serif: "Shippori Mincho", "Yu Mincho", "YuMincho", "Hiragino Mincho ProN", serif;
  --sans: "Noto Sans JP", "Hiragino Sans", "Yu Gothic", "YuGothic", sans-serif;
  --wrap: 1040px;
  --gutter: 24px;
  --header-h: 64px;
}

*, *::before, *::after { box-sizing: border-box; }

html { scroll-behavior: smooth; scroll-padding-top: var(--header-h); -webkit-text-size-adjust: 100%; }

body {
  margin: 0;
  background: var(--paper);
  color: var(--ink);
  font-family: var(--sans);
  font-size: 16px;
  line-height: 1.9;
  letter-spacing: 0.03em;
  font-feature-settings: "palt" 0;
}

a { color: inherit; }
img { max-width: 100%; }
h1, h2, h3 { margin: 0; font-weight: 600; }
p { margin: 0; }
ul, ol { margin: 0; padding: 0; list-style: none; }

.wrap { max-width: var(--wrap); margin: 0 auto; padding: 0 var(--gutter); }
.pc { display: inline; }

/* ---------- Header ---------- */
.site-header {
  position: sticky; top: 0; z-index: 10;
  background: var(--paper);
  border-bottom: 1px solid var(--rule);
}
.header-inner { display: flex; align-items: center; justify-content: space-between; height: var(--header-h); }
.brand { font-family: var(--serif); font-size: 18px; font-weight: 600; text-decoration: none; letter-spacing: 0.06em; }
.brand-note { font-size: 0.7em; color: var(--ink-mute); margin-left: 2px; }
.site-nav { display: flex; align-items: center; gap: 28px; font-size: 14px; }
.site-nav a { text-decoration: none; color: var(--ink-sub); }
.site-nav a:hover { color: var(--ink); text-decoration: underline; text-underline-offset: 4px; }
.site-nav .nav-cta { color: var(--ink); border: 1px solid var(--ink); padding: 6px 16px; }
.site-nav .nav-cta:hover { background: var(--ink); color: var(--paper); text-decoration: none; }
.nav-toggle { display: none; }

/* ---------- Buttons ---------- */
.btn {
  display: inline-block;
  padding: 14px 32px;
  font-family: var(--sans); font-size: 15px; font-weight: 500; letter-spacing: 0.08em;
  text-decoration: none; cursor: pointer;
  border: 1px solid var(--ink);
  border-radius: 0;
  transition: background-color .2s, color .2s;
}
.btn-solid { background: var(--ink); color: var(--paper); }
.btn-solid:hover { background: var(--paper); color: var(--ink); }
.btn-line { background: var(--paper); color: var(--ink); }
.btn-line:hover { background: var(--ink); color: var(--paper); }
.btn:focus-visible, a:focus-visible, summary:focus-visible, input:focus-visible, textarea:focus-visible, button:focus-visible {
  outline: 2px solid var(--ink); outline-offset: 3px;
}

/* ---------- Hero ---------- */
.hero { padding: 120px 0 112px; border-bottom: 1px solid var(--rule); }
.hero-label {
  display: inline-block;
  font-size: 14px; letter-spacing: 0.14em;
  border-top: 1px solid var(--ink); border-bottom: 1px solid var(--ink);
  padding: 6px 0;
  margin-bottom: 40px;
}
.hero-title {
  font-family: var(--serif);
  font-size: clamp(40px, 7.4vw, 84px);
  line-height: 1.35;
  letter-spacing: 0.06em;
  margin-bottom: 36px;
}
.hero-sub { font-size: 17px; color: var(--ink-sub); line-height: 2.1; max-width: 640px; }
.hero-actions { display: flex; flex-wrap: wrap; gap: 16px; margin-top: 48px; }
.hero-status { margin-top: 40px; font-size: 14px; color: var(--ink-sub); }
.hero-status::before { content: ""; display: inline-block; width: 32px; height: 1px; background: var(--ink); vertical-align: middle; margin-right: 12px; }

/* ---------- Sections ---------- */
.section { padding: 112px 0; border-bottom: 1px solid var(--rule); }
.section-head { display: flex; align-items: baseline; gap: 24px; margin-bottom: 56px; padding-bottom: 20px; border-bottom: 1px solid var(--rule-strong); }
.section-num { font-family: var(--serif); font-size: 14px; color: var(--ink-mute); letter-spacing: 0.1em; }
.section-title { font-family: var(--serif); font-size: clamp(28px, 4vw, 40px); line-height: 1.4; letter-spacing: 0.06em; }
.title-sub { display: inline-block; font-size: 0.42em; font-family: var(--sans); font-weight: 400; color: var(--ink-sub); margin-left: 16px; letter-spacing: 0.1em; vertical-align: middle; }
.section-note { margin-top: 40px; color: var(--ink-sub); }
.section-lead { margin: -16px 0 40px; max-width: 760px; color: var(--ink-sub); }

/* Worries */
.worry-list { display: grid; grid-template-columns: 1fr 1fr; border-top: 1px solid var(--rule); }
.worry-list li {
  font-family: var(--serif); font-size: 19px; line-height: 1.8;
  padding: 32px 32px 32px 0;
  border-bottom: 1px solid var(--rule);
}
.worry-list li:nth-child(odd) { border-right: 1px solid var(--rule); }
.worry-list li:nth-child(even) { padding-left: 32px; padding-right: 0; }

/* Support */
.support-list { counter-reset: sup; border-top: 1px solid var(--rule); }
.support-list li {
  counter-increment: sup;
  display: grid; grid-template-columns: 72px 1fr 1.4fr; gap: 24px;
  padding: 36px 0;
  border-bottom: 1px solid var(--rule);
}
.support-list li::before { content: counter(sup, decimal-leading-zero); font-family: var(--serif); font-size: 15px; color: var(--ink-mute); padding-top: 4px; }
.support-list h3 { font-family: var(--serif); font-size: 20px; line-height: 1.6; }
.support-list p { color: var(--ink-sub); font-size: 15px; }

/* Terms */
.terms { margin: 0; border-top: 1px solid var(--rule); }
.terms-row { display: grid; grid-template-columns: 200px 1fr; gap: 24px; padding: 28px 0; border-bottom: 1px solid var(--rule); }
.terms dt { font-family: var(--serif); font-weight: 600; font-size: 17px; }
.terms dd { margin: 0; color: var(--ink-sub); }
.terms-row--out { background: var(--paper-alt); padding-left: 20px; padding-right: 20px; border-left: 2px solid var(--ink); }

/* Flow */
.flow { display: grid; grid-template-columns: repeat(5, 1fr); border-top: 1px solid var(--ink); }
.flow li { padding: 28px 20px 8px 0; border-right: 1px solid var(--rule); }
.flow li + li { padding-left: 20px; }
.flow li:last-child { border-right: 0; }
.flow-step { display: block; font-size: 12px; letter-spacing: 0.16em; color: var(--ink-mute); margin-bottom: 12px; }
.flow h3 { font-family: var(--serif); font-size: 19px; margin-bottom: 12px; }
.flow p { font-size: 14px; color: var(--ink-sub); line-height: 1.85; }

/* About */
.about { display: grid; grid-template-columns: 1fr 1.6fr; gap: 56px; }
.about-role { font-size: 13px; letter-spacing: 0.14em; color: var(--ink-mute); margin-bottom: 12px; }
.about-person { font-family: var(--serif); font-size: 36px; font-weight: 600; letter-spacing: 0.14em; line-height: 1.4; }
.about-affil { margin-top: 12px; color: var(--ink-sub); font-size: 15px; }
.about-list { border-top: 1px solid var(--rule); }
.about-list li { padding: 18px 0; border-bottom: 1px solid var(--rule); }
.about-list a { text-underline-offset: 4px; word-break: break-all; }
.cases { margin-top: 72px; padding: 32px 0 0; border-top: 1px solid var(--ink); }
.cases-title { font-family: var(--serif); font-size: 20px; margin-bottom: 12px; }
.cases p { color: var(--ink-sub); }

/* FAQ */
.faq { border-top: 1px solid var(--rule); }
.faq details { border-bottom: 1px solid var(--rule); }
.faq summary {
  list-style: none; cursor: pointer;
  position: relative;
  padding: 28px 48px 28px 40px;
  font-family: var(--serif); font-size: 18px; font-weight: 600; line-height: 1.7;
}
.faq summary::-webkit-details-marker { display: none; }
.faq summary::before { content: "Q"; position: absolute; left: 0; top: 28px; font-family: var(--serif); color: var(--ink-mute); }
.faq summary::after { content: "+"; position: absolute; right: 4px; top: 24px; font-family: var(--sans); font-weight: 300; font-size: 24px; }
.faq details[open] summary::after { content: "−"; }
.faq details p { position: relative; padding: 0 48px 32px 40px; color: var(--ink-sub); }
.faq details p::before { content: "A"; position: absolute; left: 0; top: 0; font-family: var(--serif); color: var(--ink); }

/* Contact */
.section--contact { border-bottom: 0; }
.contact-lead { margin-bottom: 48px; color: var(--ink-sub); }
.contact-tel { max-width: 720px; margin-bottom: 40px; padding: 28px 0 24px; border-top: 1px solid var(--ink); border-bottom: 1px solid var(--rule); }
.contact-tel-title { font-family: var(--serif); font-size: 18px; letter-spacing: 0.06em; margin-bottom: 8px; }
.contact-tel-num { font-style: normal; }
.contact-tel-num a {
  display: inline-block;
  font-family: var(--serif); font-size: clamp(30px, 6vw, 40px); font-weight: 600;
  line-height: 1.5; letter-spacing: 0.08em;
  text-decoration: none;
  border-bottom: 1px solid var(--ink);
}
.contact-tel-num a:hover { border-bottom-width: 2px; }
.contact-tel-note { margin-top: 12px; font-size: 13px; color: var(--ink-sub); }
.contact-form { max-width: 720px; }
.field { margin-bottom: 28px; }
.field label { display: block; font-size: 14px; font-weight: 500; margin-bottom: 10px; }
.req { font-size: 11px; font-weight: 400; margin-left: 10px; padding: 1px 6px; border: 1px solid var(--ink); letter-spacing: 0.08em; vertical-align: 1px; }
.field input, .field textarea {
  width: 100%;
  font: inherit; font-size: 16px; color: var(--ink);
  background: var(--paper);
  border: 0; border-bottom: 1px solid var(--ink-mute);
  border-radius: 0;
  padding: 10px 2px;
  -webkit-appearance: none; appearance: none;
}
.field textarea { border: 1px solid var(--ink-mute); padding: 12px; resize: vertical; }
.field input:focus, .field textarea:focus { outline: none; border-color: var(--ink); }
.field input:focus-visible, .field textarea:focus-visible { outline: 1px solid var(--ink); outline-offset: 2px; }
.field input::placeholder, .field textarea::placeholder { color: var(--ink-mute); }
.form-status { margin-top: 20px; font-size: 14px; color: var(--ink); min-height: 1.9em; }
.contact-alt { max-width: 720px; font-size: 15px; color: var(--ink-sub); }
.contact-alt--top { margin-bottom: 48px; padding: 20px 24px; border: 1px solid var(--ink); }
.contact-alt strong { color: var(--ink); font-weight: 500; }
.contact-alt p + p { margin-top: 8px; }
.contact-alt a { color: var(--ink); text-underline-offset: 4px; word-break: break-all; }

/* Footer */
.site-footer { border-top: 1px solid var(--ink); padding: 48px 0; }
.footer-inner { display: flex; flex-wrap: wrap; align-items: baseline; gap: 8px 32px; font-size: 13px; color: var(--ink-sub); }
.footer-brand { font-family: var(--serif); font-size: 16px; color: var(--ink); }
.footer-copy { margin-left: auto; }

/* ---------- Responsive ---------- */
@media (max-width: 900px) {
  .flow { grid-template-columns: 1fr; border-top: 0; }
  .flow li, .flow li + li { padding: 24px 0; border-right: 0; border-top: 1px solid var(--rule); display: grid; grid-template-columns: 80px 1fr; column-gap: 16px; }
  .flow li:first-child { border-top: 1px solid var(--ink); }
  .flow-step { grid-row: span 2; margin: 4px 0 0; }
  .flow h3 { margin-bottom: 4px; }
  .support-list li { grid-template-columns: 48px 1fr; }
  .support-list p { grid-column: 2; }
  .about { grid-template-columns: 1fr; gap: 32px; }
}

@media (max-width: 960px) {
  .nav-toggle {
    display: block;
    background: var(--paper); color: var(--ink);
    border: 1px solid var(--ink); border-radius: 0;
    font: inherit; font-size: 13px; letter-spacing: 0.1em;
    padding: 6px 14px; cursor: pointer;
  }
  .site-nav {
    display: none;
    position: absolute; left: 0; right: 0; top: var(--header-h);
    flex-direction: column; align-items: stretch; gap: 0;
    background: var(--paper);
    border-bottom: 1px solid var(--ink);
    padding: 0 var(--gutter);
  }
  .site-nav.is-open { display: flex; }
  .site-nav a { padding: 16px 0; border-top: 1px solid var(--rule); font-size: 15px; color: var(--ink); }
  .site-nav .nav-cta { border: 0; border-top: 1px solid var(--rule); padding: 16px 0; }
  .site-nav .nav-cta:hover { background: none; color: var(--ink); }
}

@media (max-width: 760px) {
  :root { --gutter: 16px; --header-h: 56px; }
  body { font-size: 15px; }
  .pc { display: none; }

  .hero { padding: 72px 0 72px; }
  .hero-label { margin-bottom: 28px; font-size: 13px; }
  .hero-sub { font-size: 15px; }
  .hero-actions { flex-direction: column; margin-top: 36px; }
  .hero-actions .btn { text-align: center; }

  .section { padding: 72px 0; }
  .section-head { gap: 16px; margin-bottom: 36px; }
  .title-sub { display: block; margin: 8px 0 0; font-size: 13px; }

  .worry-list { grid-template-columns: 1fr; }
  .worry-list li, .worry-list li:nth-child(even) { padding: 24px 0; border-right: 0; font-size: 17px; }
  .worry-list li:nth-child(odd) { border-right: 0; }

  .support-list li { grid-template-columns: 1fr; gap: 8px; padding: 28px 0; }
  .support-list p { grid-column: auto; }
  .support-list h3 { font-size: 18px; }

  .terms-row { grid-template-columns: 1fr; gap: 6px; padding: 22px 0; }
  .terms-row--out { padding-left: 16px; padding-right: 16px; }

  .flow li, .flow li + li { grid-template-columns: 1fr; }
  .flow-step { grid-row: auto; margin-bottom: 6px; }

  .about-person { font-size: 30px; }

  .faq summary { font-size: 16px; padding: 22px 36px 22px 32px; }
  .faq summary::before { top: 22px; }
  .faq summary::after { top: 18px; }
  .faq details p { padding: 0 8px 24px 32px; }

  .contact-form .btn { width: 100%; }
  .footer-copy { margin-left: 0; width: 100%; }
}

@media (prefers-reduced-motion: reduce) {
  html { scroll-behavior: auto; }
  .btn { transition: none; }
}