:root {
  --bg: #f7f9fb;
  --surface: #ffffff;
  --text: #1f2933;
  --muted: #66737f;
  --border: #e1e7ee;
  --accent: #2563eb;
  --accent-2: #b1603b; /* origami terracotta */
  --hero-from: #a9d6e5;
  --hero-to: #e8f3f7;
}
* { box-sizing: border-box; }
html { scroll-behavior: smooth; }
body {
  margin: 0;
  font-family: "Inter", "Zen Kaku Gothic New", "Hiragino Sans", system-ui, -apple-system, sans-serif;
  color: var(--text);
  background: var(--bg);
  line-height: 1.8;
  -webkit-font-smoothing: antialiased;
}
h2, h3 { font-family: "Inter", "Zen Kaku Gothic New", "Hiragino Sans", sans-serif; letter-spacing: .01em; }
/* ブランド名「PaperCase」だけ丸みのある Poppins */
.brand strong, .hero h1 { font-family: "Poppins", "M PLUS Rounded 1c", sans-serif; font-weight: 700; letter-spacing: .01em; }
.container { max-width: 980px; margin: 0 auto; padding: 0 20px; }
a { color: var(--accent); }

/* nav */
.nav { position: sticky; top: 0; z-index: 10; background: rgba(255,255,255,.88); backdrop-filter: blur(8px); border-bottom: 1px solid var(--border); }
.nav-inner { display: flex; align-items: center; justify-content: space-between; height: 56px; }
.brand { display: inline-flex; align-items: center; gap: 8px; text-decoration: none; color: var(--text); font-size: 17px; }
.brand img { width: 26px; height: 26px; border-radius: 6px; }
.nav-links { display: flex; align-items: center; gap: 18px; }
.nav-links a { text-decoration: none; color: var(--muted); font-size: 14px; }
.nav-links a:hover { color: var(--text); }
.nav-links a.btn { color: #fff; }
.nav-links a.btn:hover { color: #fff; }

/* buttons */
.btn { display: inline-block; background: var(--accent); color: #fff; text-decoration: none; padding: 12px 22px; border-radius: 10px; font-weight: 600; transition: transform .05s ease, background .2s; }
.btn:hover { background: #1d6fe0; }
.btn:active { transform: translateY(1px); }
.btn-sm { padding: 7px 14px; border-radius: 8px; font-size: 14px; }
.apple-ico { width: 16px; height: 16px; vertical-align: -2px; margin-right: 8px; }
/* Material Symbols（フラットアイコン） */
.ms { font-family: "Material Symbols Outlined"; font-weight: normal; font-style: normal; line-height: 1; vertical-align: -5px; -webkit-font-feature-settings: 'liga'; }
.card h3 .ms { color: var(--accent); font-size: 22px; margin-right: 6px; }
.why-list { list-style: none; padding-left: 0; }
.why-list li { display: flex; align-items: flex-start; gap: 8px; margin-bottom: 8px; }
.why-list .ms { color: var(--accent); font-size: 20px; vertical-align: -4px; flex: none; }
.btn-kofi .ms { font-size: 18px; vertical-align: -4px; margin-right: 4px; }
.btn-lg { padding: 14px 28px; font-size: 16px; }

/* Ko-fi ボタン */
.btn-kofi { display:inline-block; background:#ff5e5b; color:#fff; text-decoration:none; padding:10px 20px; border-radius:10px; font-weight:600; font-size:14px; transition:background .2s; }
.btn-kofi:hover { background:#ff4542; color:#fff; }

/* hero */
.hero { background: linear-gradient(160deg, var(--hero-from), var(--hero-to)); border-bottom: 1px solid var(--border); }
.hero-inner { text-align: center; padding: 72px 20px 80px; }
.hero-icon { width: 128px; height: 128px; border-radius: 28px; box-shadow: 0 14px 40px rgba(43,58,66,.25); }
.hero h1 { font-size: 44px; margin: 22px 0 6px; letter-spacing: .02em; }
.tagline { font-size: 20px; color: var(--accent-2); font-weight: 600; margin: 0 0 18px; }
.lead { max-width: 680px; margin: 0 auto 28px; color: #3a4753; }
.hero-cta { display: flex; flex-direction: column; align-items: center; gap: 10px; }
.hero-note { font-size: 13px; color: var(--muted); }

/* sections */
.section { padding: 64px 0; }
.section-alt { background: var(--surface); border-top: 1px solid var(--border); border-bottom: 1px solid var(--border); }
.section h2 { font-size: 28px; margin: 0 0 28px; }
.section h3 { font-size: 17px; margin: 0 0 8px; }

/* carousel (screenshots) */
.carousel { margin-top: 24px; overflow: hidden; }
.carousel-track { display: flex; transition: transform .6s cubic-bezier(.4,0,.2,1); }
.slide { flex: 0 0 100%; margin: 0; padding: 0 2px; }
.slide img { width: 100%; height: auto; display: block; border: 1px solid var(--border); border-radius: 14px; box-shadow: 0 12px 36px rgba(43,58,66,.16); background: var(--surface); }
.slide figcaption { text-align: center; color: var(--muted); font-size: 14px; margin-top: 14px; }
/* ページャ：現在位置を伸びるバーで表現 */
.carousel-dots { display: flex; justify-content: center; gap: 7px; margin-top: 18px; }
.carousel-dot { width: 8px; height: 8px; padding: 0; border-radius: 999px; border: none; background: var(--border); cursor: pointer; transition: width .35s ease, background .35s ease; }
.carousel-dot:hover { background: var(--muted); }
.carousel-dot.active { width: 26px; background: var(--accent); }

/* feature grid */
.grid { display: grid; grid-template-columns: repeat(auto-fit, minmax(230px, 1fr)); gap: 18px; }
.card { background: var(--surface); border: 1px solid var(--border); border-radius: 14px; padding: 20px; }
.section-alt .card { background: var(--bg); }
.card p { color: var(--muted); margin: 0; font-size: 14px; }

.grid-2 { display: grid; grid-template-columns: 1fr 1fr; gap: 28px; }

/* steps */
.steps { padding-left: 20px; }
.steps li { margin-bottom: 14px; }
.steps ul { margin: 8px 0; }
code { background: #eef2f6; padding: 2px 6px; border-radius: 5px; font-size: 13px; }
.section-alt code { background: #eef2f6; }

/* install screenshot */
.install-shot { margin: 16px 0 4px; max-width: 520px; }
.install-shot img { width: 100%; height: auto; display: block; border: 1px solid var(--border); border-radius: 12px; box-shadow: 0 10px 30px rgba(43,58,66,.14); }
.install-shot figcaption { font-size: 13px; color: var(--muted); margin-top: 8px; }

/* kbd tables */
.kbd-table { border-collapse: collapse; width: 100%; }
.kbd-table td { padding: 7px 8px; border-bottom: 1px solid var(--border); font-size: 14px; vertical-align: top; }
.kbd-table td:first-child { white-space: nowrap; color: var(--muted); width: 45%; }
kbd { background: #fff; border: 1px solid #cbd2d9; border-bottom-width: 2px; border-radius: 5px; padding: 1px 6px; font-size: 12px; font-family: ui-monospace, monospace; }

/* legal page */
.legal { padding: 48px 20px 72px; max-width: 760px; }
.legal h1 { font-size: 30px; margin-bottom: 4px; }
.legal h2 { font-size: 18px; margin: 28px 0 8px; }
.legal ul { padding-left: 20px; }
.legal li { margin-bottom: 6px; }

/* misc */
.muted { color: var(--muted); }
.small { font-size: 13px; }
.footer { padding: 40px 0 56px; border-top: 1px solid var(--border); background: var(--surface); text-align: center; }
.footer p { margin: 6px 0; }
.footer .small { max-width: 720px; margin: 8px auto 0; }

@media (max-width: 640px) {
  .grid-2 { grid-template-columns: 1fr; }
  .nav-links a:not(.btn) { display: none; }
  .hero h1 { font-size: 34px; }
}