body {
  background: radial-gradient(ellipse at center, #ffeaea 0%, #fff 100%);
  font-family: 'Noto Sans JP', 'Montserrat', Arial, sans-serif;
  color: #232323;
  margin: 0;
  padding: 0;
}

header {
  text-align: center;
  padding: 44px 7px 18px 7px;
}

.brand-row {
  display: flex;
  align-items: center;
  justify-content: center;
  gap: 17px;
  margin-bottom: 8px;
}

.logo {
  width: 60px;
  height: 60px;
  display: block;
  margin: 0;
}

h1 {
  font-size: 2.5em;
  letter-spacing: 0.04em;
  font-weight: 900;
  margin: 0;
  color: #ff7676;
  text-shadow: 0 2px 9px #ff767624, 0 1.5px 0 #fff;
  line-height: 1.1;
}

.tagline {
  font-size: 1.12em;
  margin-bottom: 24px;
  margin-top: 4px;
  color: #ff7676;
}

.demo-gif-wrapper {
  margin: 16px auto 9px auto;
  max-width: 530px;
  width: 100%;
  display: flex;
  justify-content: center;
}

.demo-gif {
  width: 97%;
  max-width: 490px;
  min-width: 180px;
  border-radius: 12px;
  box-shadow: 0 2px 12px #d868b627;
  display: block;
}

section {
  max-width: 500px;
  margin: 32px auto 22px auto;
  padding: 18px;
  background: #fff6f6;
  border-radius: 14px;
  box-shadow: 0 1px 9px #ff76761c;
  font-size: 1.05em;
}

.benefits ul {
  list-style: none;
  padding: 0;
}
.benefits li {
  font-size: 1.05em;
  margin-bottom: 8px;
  letter-spacing: 0.01em;
}

/* -------- Howto tabs/panels -------- */
.howto-tab-panel {
  display: flex;
  gap: 11px;
  margin-bottom: 19px;
}
.howto-tab {
  background: #f4ecf4;
  border: none;
  border-radius: 24px 24px 0 0;
  font-size: 1.04em;
  font-family: inherit;
  color: #d28b1d;
  font-weight: 700;
  padding: 7px 28px;
  cursor: pointer;
  transition: background 0.18s, color 0.18s;
  outline: none;
  box-shadow: 0 2px 8px #f9d7ca29;
}
.howto-tab.active {
  background: #ffe6b3;
  color: #e15925;
  border-bottom: 3px solid #faad25;
  z-index: 2;
}

.howto-video-wrapper {
  width: 100%;
  margin: 12px 0 18px 0;
  display: flex;
  justify-content: center;
}
.howto-video {
  width: 100%;
  max-width: 600px;
  aspect-ratio: 16/9;
  border-radius: 10px;
  box-shadow: 0 2px 18px #b74d4d15;
  border: none;
  background: #000;
  object-fit: contain;
}

.install-note {
  background: #fff2cf;
  color: #b85f0b;
  font-size: 0.98em;
  margin: 17px auto 0 auto;
  padding: 9px 13px;
  border-radius: 8px;
  max-width: 490px;
  text-align: center;
  box-shadow: 0 1px 7px #eedfbc82;
}

.faq h2, .howto h2, .benefits h2 {
  font-size: 1.13em;
  margin-bottom: 12px;
}

.faq dt {
  font-weight: bold;
  margin-top: 10px;
}
.faq dd {
  margin-left: 0;
  margin-bottom: 6px;
}

.cta-container {
  display: flex;
  justify-content: center;
  margin: 27px 0 14px 0;
}

.buy-btn {
  background: #FF7676;
  color: #fff;
  font-size: 1em;
  padding: 11px 23px;
  border-radius: 50px;
  text-decoration: none;
  font-weight: 700;
  box-shadow: 0 3px 12px #ff767637;
  transition: background 0.2s, transform 0.2s;
  margin-bottom: 0;
  display: inline-block;
}
.buy-btn:hover {
  background: #ff4d4d;
  transform: scale(1.06);
}

footer {
  text-align: center;
  color: #878787;
  padding: 15px 0 10px 0;
  font-size: 0.93em;
  margin-top: 30px;
}

/* --- MOBILE OPTIMIZATION --- */
@media (max-width: 800px) {
  section { max-width: 99vw; }
  .howto-video { max-width: 99vw; }
  .install-note { max-width: 98vw; }
}
@media (max-width: 600px) {
  .logo { width: 52px; height: 52px; }
  .brand-row { gap: 10px; }
  h1 { font-size: 1.45em; }
  .tagline { font-size: 0.92em; }
  header { padding: 22px 2vw 11px 2vw; }
  .demo-gif-wrapper { margin: 9px 0 4px 0; }
  .demo-gif { width: 99%; max-width: 99vw; min-width: 75px; }
  section {
    padding: 7px;
    border-radius: 8px;
    font-size: 0.87em;
    margin: 22px auto 13px auto;
  }
  .benefits li,
  .faq h2,
  .howto h2,
  .benefits h2 {
    font-size: 0.90em;
  }
  .buy-btn {
    font-size: 0.94em;
    padding: 9px 13px;
  }
  .howto-tab-panel { gap: 7px; }
  .howto-tab { font-size: 0.95em; padding: 6px 11px; }
  .install-note {
    font-size: 0.88em;
    padding: 6px 7px;
    max-width: 99vw;
    border-radius: 5px;
  }
  footer { font-size: 0.85em; margin-top: 14px; }
}