:root {
  --accent: #ff5f5f;
  --bg: #000000;
  --bg-soft: #111111;
  --text: #ffffff;
  --text-muted: #aaaaaa;
  --card: rgba(255,255,255,0.04);
}

* {
  box-sizing: border-box;
}

body {
  margin: 0;
  font-family: 'Noto Sans JP', sans-serif;
  background: linear-gradient(180deg, var(--bg) 0%, var(--bg-soft) 100%);
  color: var(--text);
  line-height: 1.8;
}

header {
  padding: 22px 20px;
  border-bottom: 1px solid rgba(255,255,255,0.1);
  background: rgba(0, 0, 0, 0.28);
  backdrop-filter: blur(6px);
}

.header-inner {
  max-width: 1100px;
  margin: 0 auto;
  text-align: center;
  font-weight: 700;
  font-size: 18px;
  letter-spacing: 0.02em;
}

.container {
  max-width: 900px;
  margin: 80px auto;
  padding: 40px;
  background: var(--card);
  border-radius: 18px;
  backdrop-filter: blur(12px);
  border: 1px solid rgba(255,255,255,0.08);
  text-align: center;
}

h1 {
  font-size: 32px;
  margin-bottom: 30px;
  color: var(--accent);
  line-height: 1.4;
}

h2 {
  margin-top: 40px;
  margin-bottom: 10px;
  font-size: 20px;
  color: var(--accent);
}

p {
  margin-bottom: 16px;
  color: var(--text-muted);
  max-width: 760px;
  margin-left: auto;
  margin-right: auto;
}

ul {
  display: inline-block;
  text-align: left;
  padding-left: 20px;
  margin: 0 auto 24px;
  color: var(--text-muted);
}

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

a:hover {
  opacity: 0.7;
}

footer {
  text-align: center;
  padding: 40px;
  border-top: 1px solid rgba(255,255,255,0.1);
  margin-top: 100px;
  font-size: 14px;
  color: var(--text-muted);
}

.sitemap-title {
  margin: 0 0 14px;
  color: var(--text);
  font-weight: 700;
  letter-spacing: 0.02em;
}

.footer-links {
  display: flex;
  flex-wrap: wrap;
  justify-content: center;
  gap: 8px 16px;
  margin: 0;
}

.footer-links a {
  color: var(--text-muted);
}

.footer-links a:hover {
  color: var(--accent);
}

.copyright {
  margin: 16px 0 0;
}

#sent-message {
  color: #9ee6b0;
  margin-top: 14px;
  font-weight: 600;
}

.btn {
  display: inline-block;
  padding: 12px 24px;
  background: var(--accent);
  color: #fff;
  border-radius: 12px;
  margin-top: 20px;
  font-weight: 600;
}

.btn:hover {
  opacity: 0.8;
}

form {
  width: 100%;
  max-width: 680px;
  margin: 24px auto 0;
  display: grid;
  gap: 14px;
}

input,
textarea {
  width: 100%;
  max-width: none;
  padding: 12px;
  margin-top: 0;
  background: rgba(255, 255, 255, 0.05);
  border: 1px solid rgba(255, 255, 255, 0.15);
  color: var(--text);
  border-radius: 8px;
  font-family: inherit;
}

textarea {
  min-height: 180px;
  resize: vertical;
}

button {
  margin-top: 0;
  padding: 12px 24px;
  background: var(--accent);
  border: none;
  color: #fff;
  border-radius: 10px;
  cursor: pointer;
  font-weight: 600;
  width: fit-content;
  min-width: 120px;
  justify-self: end;
}

@media (max-width: 768px) {
  header {
    padding: 16px 12px;
  }

  .header-inner {
    font-size: 16px;
  }

  .container {
    margin: 32px 12px;
    padding: 24px 16px;
    border-radius: 14px;
  }

  h1 {
    font-size: 24px;
    margin-bottom: 20px;
  }

  h2 {
    font-size: 18px;
    margin-top: 28px;
  }

  .btn,
  button {
    width: 100%;
    max-width: 320px;
  }

  form {
    gap: 12px;
  }

  form button {
    max-width: none;
    justify-self: stretch;
  }

  input,
  textarea {
    max-width: 100%;
  }

  footer {
    margin-top: 56px;
    padding: 28px 20px;
    line-height: 1.9;
  }

  .footer-links {
    gap: 6px 12px;
  }
}