/* ── つなポン 紹介ページの配色 ─────────────────────────────────────────
   iOS アプリの「ポップ・イエロー」テーマ（tsunapon/UI/Theme.swift）をそのまま反映。
   bg #FFFBE6   section #FFF3C4   card #FFFFFF   line rgba(27,27,27,.75)
   ink #1B1B1B  muted #5A5440     main #FF3B5C   accent #2F6BFF
   tile #FFF8E6 grid #F1EAD0     good #00B26B
   グラデーション（カードの縁・見出しの帯）  #FF5C8A → #FF9F43 → #FFD21F
   （パズルちゃんの紹介ページ styles.css の構成を踏襲。あちらは淡い青、こちらは黄色）

   文字はアプリと同じ。見出しは Mochiy Pop One、本文は M PLUS Rounded 1c。
*/
* {
  margin: 0;
  padding: 0;
  box-sizing: border-box;
}

:root {
  --bg: #fffbe6;
  --section: #fff3c4;
  --ink: #1b1b1b;
  --muted: #5a5440;
  --line: rgba(27, 27, 27, 0.75);
  --main: #ff3b5c;
  --accent: #2f6bff;
  --tile: #fff8e6;
  --grid: #f1ead0;
  --pink-grad: linear-gradient(135deg, #ff5c8a, #ff9f43 55%, #ffd21f);
  --display: "Mochiy Pop One", "M PLUS Rounded 1c", -apple-system, sans-serif;
}

body {
  font-family: "M PLUS Rounded 1c", -apple-system, BlinkMacSystemFont, sans-serif;
  font-weight: 500;
  line-height: 1.85;
  color: var(--ink);
  background-color: var(--bg);
}

.container {
  max-width: 1120px;
  margin: 0 auto;
  padding: 0 20px;
}

/* Header */
.header {
  background-color: rgba(255, 251, 230, 0.88);
  backdrop-filter: blur(12px);
  -webkit-backdrop-filter: blur(12px);
  box-shadow: 0 1px 0 var(--grid);
  position: fixed;
  top: 0;
  left: 0;
  right: 0;
  z-index: 1000;
}

.nav-container {
  max-width: 1120px;
  margin: 0 auto;
  padding: 0 20px;
  display: flex;
  justify-content: space-between;
  align-items: center;
  height: 70px;
}

.nav-logo {
  display: flex;
  align-items: center;
  gap: 10px;
  text-decoration: none;
}

.nav-logo-mark {
  width: 32px;
  height: 32px;
  border-radius: 9px;
  border: 1.5px solid var(--line);
}

.nav-logo h1 {
  font-family: var(--display);
  font-size: 1.1rem;
  font-weight: 400;
  color: var(--ink);
}

.nav-menu {
  display: flex;
  gap: 22px;
  list-style: none;
}

.nav-menu a {
  color: var(--muted);
  text-decoration: none;
  font-size: 0.92rem;
  font-weight: 700;
  transition: color 0.2s ease;
}

.nav-menu a:hover {
  color: var(--main);
}

.language-switcher {
  display: flex;
  align-items: center;
  gap: 6px;
}

.lang-btn {
  background: none;
  border: none;
  color: #a39b7f;
  font-family: inherit;
  font-size: 0.85rem;
  font-weight: 800;
  cursor: pointer;
  padding: 4px 2px;
  transition: color 0.2s ease;
}

.lang-btn:hover,
.lang-btn.active {
  color: var(--main);
}

.lang-separator {
  color: #e2d6a6;
  font-size: 0.85rem;
}

/* Hero：アプリのホームと同じ、背景は黄色にドット */
.hero {
  padding: 140px 0 90px;
  background:
    radial-gradient(rgba(0, 0, 0, 0.08) 1.6px, transparent 1.8px) 0 0 / 18px 18px,
    radial-gradient(900px 420px at 80% 10%, #fff7d1 0%, rgba(255, 247, 209, 0) 62%),
    linear-gradient(#fffbe6, #ffe98f);
}

.hero-container {
  max-width: 1120px;
  margin: 0 auto;
  padding: 0 20px;
  display: grid;
  grid-template-columns: 1.1fr 0.9fr;
  gap: 56px;
  align-items: center;
}

.hero-balls {
  display: flex;
  gap: 4px;
  margin-bottom: 14px;
}

.hero-balls img {
  width: 56px;
  height: 56px;
  animation: bob 3.2s ease-in-out infinite;
  animation-delay: calc(var(--i) * -0.45s);
}

@keyframes bob {
  50% {
    transform: translateY(-8px);
  }
}

.hero-logo img {
  display: block;
  width: min(420px, 100%);
  height: auto;
}

.hero-tagline {
  font-family: var(--display);
  font-size: clamp(1.05rem, 2.2vw, 1.3rem);
  margin: 14px 0 16px;
}

.hero-description {
  font-size: 1rem;
  color: var(--muted);
  margin-bottom: 30px;
  max-width: 34em;
}

.hero-buttons {
  display: flex;
  gap: 14px;
  flex-wrap: wrap;
}

.btn {
  display: inline-block;
  padding: 13px 30px;
  border-radius: 999px;
  border: 1.5px solid var(--line);
  text-decoration: none;
  font-family: var(--display);
  font-size: 0.98rem;
  transition: transform 0.15s ease, box-shadow 0.15s ease;
}

/* アプリのホームの「CPU対戦」ボタンと同じ赤 */
.btn-primary {
  background: var(--main);
  color: #fff;
  box-shadow: 4px 4px 0 var(--ink);
}

.btn-primary:hover {
  transform: translate(-1px, -1px);
  box-shadow: 5px 5px 0 var(--ink);
}

.btn-outline {
  background: #fff;
  color: var(--ink);
}

.btn-outline:hover {
  transform: translateY(-1px);
}

.hero-image {
  display: flex;
  justify-content: center;
}

.app-icon-placeholder {
  width: 240px;
  height: 240px;
  border-radius: 54px;
  overflow: hidden;
  background: #fff;
  border: 3px solid var(--ink);
  box-shadow: 8px 8px 0 var(--ink);
  transform: rotate(-3deg);
}

.app-icon-image {
  width: 100%;
  height: 100%;
  object-fit: cover;
  display: block;
}

/* Sections：見出しはアプリのカードの見出しと同じ、グラデーションの帯 */
.section-title {
  display: block;
  width: max-content;
  max-width: 100%;
  margin: 0 auto 16px;
  padding: 6px 26px;
  border-radius: 999px;
  background: var(--pink-grad);
  color: #fff;
  font-family: var(--display);
  font-weight: 400;
  font-size: clamp(1.3rem, 2.4vw, 1.7rem);
  text-align: center;
  line-height: 1.5;
}

.section-lead {
  text-align: center;
  color: var(--muted);
  font-size: 0.98rem;
  max-width: 46em;
  margin: 0 auto 40px;
  text-wrap: balance;
}

.modes .section-title,
.features .section-title,
.download .section-title,
.privacy .section-title,
.contact .section-title {
  margin-bottom: 44px;
}

.sub-title {
  font-family: var(--display);
  font-weight: 400;
  font-size: 1.2rem;
  text-align: center;
  margin: 56px 0 22px;
}

/* 共通のカード：白地に細い黒フチ（アプリのカードと同じ） */
.step-card,
.burst-card,
.mode-card,
.feature-card,
.download-info,
.download-requirements,
.privacy-content,
.contact-method {
  background: #fff;
  border: 1.5px solid var(--line);
  border-radius: 22px;
  transition: transform 0.2s ease, box-shadow 0.2s ease;
}

.step-card:hover,
.mode-card:hover,
.feature-card:hover {
  transform: translateY(-3px);
  box-shadow: 0 10px 24px rgba(160, 120, 20, 0.16);
}

/* How to play */
.howto {
  padding: 88px 0;
  background-color: var(--bg);
}

.steps-grid {
  display: grid;
  grid-template-columns: repeat(auto-fit, minmax(290px, 1fr));
  gap: 20px;
}

.step-card {
  position: relative;
  padding: 24px 22px;
}

.step-card h3 {
  font-family: var(--display);
  font-weight: 400;
  font-size: 1.15rem;
  margin: 14px 0 6px;
}

.step-card p {
  font-size: 0.92rem;
  color: var(--muted);
}

/* いちばん点が入る「ミックスバースト」は目立たせる */
.step-card-hot,
.burst-card-hot {
  border: 3px solid transparent;
  background:
    linear-gradient(135deg, #fff0f5, #fff6e0) padding-box,
    var(--pink-grad) border-box;
}

.step-card-hot h3 {
  color: #ff3b7a;
}

.hot-badge {
  position: absolute;
  top: -14px;
  right: 18px;
  padding: 3px 12px;
  border-radius: 999px;
  background: linear-gradient(90deg, #ff5c8a, #ff9f43);
  color: #fff;
  font-size: 0.8rem;
  font-weight: 800;
}

/* 玉 ─色─ 玉 ─数字─ 玉 の図（アプリの遊び方と同じ） */
.step-demo {
  display: flex;
  align-items: center;
  justify-content: center;
  padding: 14px 6px;
  border-radius: 16px;
  background: var(--tile);
}

.step-demo img {
  width: 44px;
  height: 44px;
}

.link {
  display: block;
  width: 20px;
  height: 5px;
  border-radius: 3px;
  margin: 0 2px;
}

.link.color {
  background: #ff7a45;
}

.link.number {
  background: #2f9bff;
}

.bursts-grid {
  display: grid;
  grid-template-columns: repeat(auto-fit, minmax(250px, 1fr));
  gap: 14px;
}

.burst-card {
  display: flex;
  align-items: flex-start;
  gap: 12px;
  padding: 16px 18px;
}

.burst-icon {
  flex: none;
  width: 40px;
  height: 40px;
  border-radius: 12px;
  background: var(--tile);
  display: flex;
  align-items: center;
  justify-content: center;
  font-size: 1.25rem;
}

.burst-card h4 {
  font-family: var(--display);
  font-weight: 400;
  font-size: 1rem;
  margin-bottom: 2px;
}

.burst-card-hot h4 {
  color: #ff3b7a;
}

.burst-card p {
  font-size: 0.86rem;
  color: var(--muted);
  line-height: 1.7;
}

/* Modes */
.modes {
  padding: 88px 0;
  background-color: var(--section);
}

.modes-grid {
  display: grid;
  grid-template-columns: repeat(auto-fit, minmax(290px, 1fr));
  gap: 20px;
}

.mode-card {
  padding: 24px 22px;
}

.mode-head {
  display: flex;
  align-items: center;
  gap: 14px;
  margin-bottom: 12px;
}

.mode-icon {
  flex: none;
  width: 52px;
  height: 52px;
  border-radius: 16px;
  display: flex;
  align-items: center;
  justify-content: center;
  color: #fff;
  font-family: var(--display);
  font-size: 1.4rem;
}

.mode-icon-vs {
  font-size: 1.05rem;
  background: linear-gradient(135deg, #ff5c8a, #ff9f43 55%, #ffd21f);
}

.mode-icon-free {
  background: linear-gradient(135deg, #2f9bff, #3fd0e0 55%, #7be495);
}

.mode-icon-mission {
  background: linear-gradient(135deg, #9b5cff, #ff6fd0 55%, #ffb347);
}

.mode-card h3 {
  font-family: var(--display);
  font-weight: 400;
  font-size: 1.25rem;
}

.mode-card p {
  font-size: 0.92rem;
  color: var(--muted);
}

.mode-chars {
  display: flex;
  gap: 2px;
  margin-top: 14px;
}

.mode-chars img {
  width: 52px;
  height: 52px;
}

/* Features */
.features {
  padding: 88px 0;
  background-color: var(--bg);
}

.features-grid {
  display: grid;
  grid-template-columns: repeat(auto-fit, minmax(268px, 1fr));
  gap: 20px;
}

.feature-card {
  padding: 24px 22px;
}

.feature-icon {
  margin-bottom: 12px;
}

.icon-placeholder {
  width: 52px;
  height: 52px;
  border-radius: 50%;
  background: #ffe45c;
  border: 1.5px solid var(--line);
  display: flex;
  align-items: center;
  justify-content: center;
  font-size: 1.45rem;
}

.feature-card h3 {
  font-family: var(--display);
  font-weight: 400;
  font-size: 1.05rem;
  margin-bottom: 6px;
}

.feature-card p {
  font-size: 0.92rem;
  color: var(--muted);
}

/* Download */
.download {
  padding: 88px 0;
  background-color: var(--section);
}

.download-content {
  display: grid;
  grid-template-columns: 1.2fr 0.8fr;
  gap: 28px;
  align-items: stretch;
}

.download-info,
.download-requirements {
  padding: 30px 28px;
}

.download-info h3 {
  font-family: var(--display);
  font-weight: 400;
  font-size: 1.2rem;
  margin-bottom: 8px;
}

.download-info p {
  color: var(--muted);
  font-size: 0.94rem;
  margin-bottom: 22px;
}

.app-store-placeholder {
  display: inline-block;
  padding: 13px 30px;
  border-radius: 999px;
  border: 1.5px solid var(--line);
  background: var(--main);
  color: #fff;
  text-decoration: none;
  font-family: var(--display);
  font-size: 0.98rem;
  box-shadow: 4px 4px 0 var(--ink);
  transition: transform 0.15s ease, box-shadow 0.15s ease;
}

.app-store-placeholder:hover {
  transform: translate(-1px, -1px);
  box-shadow: 5px 5px 0 var(--ink);
}

.download-requirements h4 {
  font-size: 0.98rem;
  font-weight: 800;
  margin-bottom: 12px;
}

.download-requirements ul {
  list-style: none;
}

.download-requirements li {
  color: var(--muted);
  font-size: 0.92rem;
  padding: 7px 0 7px 20px;
  position: relative;
  border-bottom: 1px dashed #eadfbe;
}

.download-requirements li:last-child {
  border-bottom: none;
}

.download-requirements li::before {
  content: "●";
  position: absolute;
  left: 2px;
  font-size: 0.6rem;
  top: 13px;
  color: var(--main);
}

/* Privacy */
.privacy {
  padding: 88px 0;
  background-color: var(--bg);
}

.privacy-content {
  padding: 36px 34px;
  max-width: 860px;
  margin: 0 auto;
}

.privacy-content h3 {
  font-size: 1.1rem;
  font-weight: 800;
  margin-bottom: 12px;
}

.privacy-content h4 {
  font-size: 0.98rem;
  font-weight: 800;
  margin: 26px 0 8px;
}

.privacy-content p {
  color: var(--muted);
  font-size: 0.93rem;
}

.privacy-content a {
  color: var(--accent);
}

.privacy-update {
  margin-top: 30px;
  padding-top: 18px;
  border-top: 1px dashed #eadfbe;
  font-size: 0.84rem !important;
  color: #a39b7f !important;
}

/* Contact */
.contact {
  padding: 88px 0;
  background-color: var(--section);
}

.contact-content {
  max-width: 900px;
  margin: 0 auto;
  text-align: center;
}

.contact-content > p {
  color: var(--muted);
  margin-bottom: 36px;
}

.contact-methods {
  display: grid;
  grid-template-columns: repeat(auto-fit, minmax(232px, 1fr));
  gap: 20px;
  text-align: left;
}

.contact-method {
  padding: 24px;
}

.contact-method h3 {
  font-size: 0.98rem;
  font-weight: 800;
  margin-bottom: 8px;
}

.contact-method p,
.contact-method a {
  font-size: 0.9rem;
  color: var(--muted);
}

.contact-method a {
  color: var(--accent);
  text-decoration: none;
}

.contact-method a:hover {
  text-decoration: underline;
}

/* Footer */
.footer {
  background: var(--bg);
  border-top: 1px solid var(--grid);
  padding: 30px 0;
}

.footer-bottom {
  text-align: center;
  color: #a39b7f;
  font-size: 0.84rem;
}

/* Animation */
@keyframes fadeInUp {
  from {
    opacity: 0;
    transform: translateY(18px);
  }
  to {
    opacity: 1;
    transform: translateY(0);
  }
}

.fade-in-up {
  animation: fadeInUp 0.5s ease forwards;
}

@media (prefers-reduced-motion: reduce) {
  * {
    animation: none !important;
    transition: none !important;
  }
}

/* Responsive */
@media (max-width: 900px) {
  .hero-container,
  .download-content {
    grid-template-columns: 1fr;
  }

  .hero {
    padding: 120px 0 72px;
    text-align: center;
  }

  .hero-balls {
    justify-content: center;
  }

  .hero-logo img {
    margin: 0 auto;
  }

  .hero-description {
    margin-left: auto;
    margin-right: auto;
  }

  .hero-buttons {
    justify-content: center;
  }

  .hero-image {
    display: none;
  }
}

@media (max-width: 640px) {
  .nav-menu {
    display: none;
  }

  .hero-balls img {
    width: 46px;
    height: 46px;
  }

  .step-demo img {
    width: 38px;
    height: 38px;
  }

  .link {
    width: 14px;
  }

  .privacy-content {
    padding: 26px 20px;
  }
}