/* ==========================================================================
   Design Tokens (semaphore.io 風カラーパレット)
   ========================================================================== */
:root {
  /* Base surfaces */
  --color-bg: #0F0D1E;
  --color-bg-alt: #171432;
  --color-surface: #1E1A3A;
  --color-surface-hover: #262047;
  --color-border: #322C55;

  /* Brand accent (purple -> pink gradient) */
  --color-primary: #2865DE;
  --color-primary-light: #2865DE;
  --color-primary-dark: #2865DE;
  --color-secondary: #2865DE;
  --color-gradient: linear-gradient(135deg, #2865DE 0%, #2865DE 100%);

  /* Text */
  --color-text: #F5F3FF;
  --color-text-muted: #ABA6C3;
  --color-text-inverse: #14101F;

  /* Radius */
  --radius-base: 8px;

  /* Spacing */
  --container-width: 1120px;
}

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

html {
  scroll-behavior: smooth;
}

body {
  margin: 0;
  font-family: "Hiragino Kaku Gothic ProN", "Noto Sans JP", sans-serif;
  background-color: var(--color-bg);
  color: var(--color-text);
  line-height: 1.7;
}

ul,
ol {
  list-style: none;
  margin: 0;
  padding: 0;
}

a {
  color: inherit;
  text-decoration: none;
}

img {
  max-width: 100%;
  display: block;
}

button {
  font: inherit;
  cursor: pointer;
}

/* ==========================================================================
   Header
   ========================================================================== */
.header {
  position: sticky;
  top: 0;
  z-index: 100;
  background-color: rgba(15, 13, 30, 0.85);
  backdrop-filter: blur(8px);
  border-bottom: 1px solid var(--color-border);
}

.header__inner {
  max-width: var(--container-width);
  margin: 0 auto;
  padding: 16px 24px;
  display: flex;
  align-items: center;
  justify-content: space-between;
}

.header__logo {
  display: flex;
  align-items: center;
  gap: 8px;
}

.header__logo-image {
  width: 32px;
  height: 32px;
  border-radius: var(--radius-base);
}

.header__logo-text {
  font-weight: 700;
  font-size: 1.1rem;
  color: var(--color-text);
}

.header__toggle {
  display: none;
  flex-direction: column;
  gap: 5px;
  background: none;
  border: none;
  padding: 8px;
  border-radius: var(--radius-base);
}

.header__toggle:hover {
  background-color: var(--color-surface);
}

.header__toggle-bar {
  width: 22px;
  height: 2px;
  background-color: var(--color-text);
  border-radius: var(--radius-base);
}

.header__nav-list {
  display: flex;
  align-items: center;
  gap: 32px;
}

.header__nav-link {
  font-size: 0.95rem;
  color: var(--color-text-muted);
  transition: color 0.2s ease;
}

.header__nav-link:hover {
  color: var(--color-text);
}

.header__nav-link--cta {
  padding: 10px 20px;
  border-radius: var(--radius-base);
  background: var(--color-gradient);
  color: var(--color-text);
  font-weight: 700;
}

.header__nav-link--cta:hover {
  opacity: 0.9;
}

/* ==========================================================================
   Hero
   ========================================================================== */
.hero {
  background:
    radial-gradient(circle at 20% 20%, rgba(124, 92, 252, 0.25), transparent 45%),
    radial-gradient(circle at 80% 30%, rgba(255, 107, 157, 0.2), transparent 40%),
    var(--color-bg);
  padding: 96px 24px;
}

.hero__inner {
  max-width: var(--container-width);
  margin: 0 auto;
  display: flex;
  align-items: center;
  gap: 48px;
}

.hero__content {
  flex: 1;
}

.hero__badge {
  display: inline-block;
  padding: 6px 14px;
  border-radius: var(--radius-base);
  background-color: var(--color-surface);
  border: 1px solid var(--color-border);
  color: var(--color-primary-light);
  font-size: 0.8rem;
  font-weight: 700;
  letter-spacing: 0.05em;
  margin-bottom: 24px;
}

.hero__title {
  font-size: 2.75rem;
  line-height: 1.4;
  margin: 0 0 20px;
  color: var(--color-text);
}

.hero__subtitle {
  font-size: 1.05rem;
  color: var(--color-text-muted);
  margin: 0 0 32px;
  max-width: 480px;
}

.hero__cta {
  display: inline-block;
  padding: 16px 36px;
  border-radius: var(--radius-base);
  background: var(--color-gradient);
  color: var(--color-text);
  font-weight: 700;
  font-size: 1rem;
  box-shadow: 0 8px 24px rgba(124, 92, 252, 0.35);
  transition: transform 0.2s ease, box-shadow 0.2s ease;
}

.hero__cta:hover {
  transform: translateY(-2px);
  box-shadow: 0 12px 28px rgba(124, 92, 252, 0.45);
}

.hero__visual {
  flex: 1;
}

.hero__image {
  border-radius: var(--radius-base);
  border: 1px solid var(--color-border);
}

/* ==========================================================================
   Features
   ========================================================================== */
.features {
  padding: 96px 24px;
  background-color: var(--color-bg-alt);
}

.features__inner {
  max-width: var(--container-width);
  margin: 0 auto;
}

.features__heading {
  text-align: center;
  font-size: 2rem;
  margin: 0 0 48px;
  color: var(--color-text);
}

.features__list {
  display: grid;
  grid-template-columns: repeat(3, 1fr);
  gap: 24px;
}

.features__item {
  padding: 32px 24px;
  border-radius: var(--radius-base);
  background-color: var(--color-surface);
  border: 1px solid var(--color-border);
  transition: background-color 0.2s ease, transform 0.2s ease;
}

.features__item:hover {
  background-color: var(--color-surface-hover);
  transform: translateY(-4px);
}

.features__icon {
  font-size: 2rem;
  margin-bottom: 16px;
}

.features__title {
  font-size: 1.15rem;
  margin: 0 0 12px;
  color: var(--color-text);
}

.features__text {
  font-size: 0.95rem;
  color: var(--color-text-muted);
  margin: 0;
}

/* ==========================================================================
   Contact
   ========================================================================== */
.contact {
  padding: 96px 24px;
  background-color: var(--color-bg);
}

.contact__inner {
  max-width: 560px;
  margin: 0 auto;
  text-align: center;
}

.contact__heading {
  font-size: 2rem;
  margin: 0 0 16px;
  color: var(--color-text);
}

.contact__text {
  color: var(--color-text-muted);
  margin: 0 0 40px;
}

.contact__form {
  text-align: left;
  display: flex;
  flex-direction: column;
  gap: 20px;
}

.contact__field {
  display: flex;
  flex-direction: column;
  gap: 8px;
}

.contact__label {
  font-size: 0.9rem;
  color: var(--color-text-muted);
}

.contact__input,
.contact__textarea {
  padding: 14px 16px;
  border-radius: var(--radius-base);
  border: 1px solid var(--color-border);
  background-color: var(--color-surface);
  color: var(--color-text);
  font: inherit;
  resize: vertical;
}

.contact__input:focus,
.contact__textarea:focus {
  outline: none;
  border-color: var(--color-primary);
  box-shadow: 0 0 0 3px rgba(124, 92, 252, 0.25);
}

.contact__button {
  align-self: flex-start;
  padding: 14px 36px;
  border: none;
  border-radius: var(--radius-base);
  background: var(--color-gradient);
  color: var(--color-text-inverse);
  font-weight: 700;
  box-shadow: 0 8px 24px rgba(124, 92, 252, 0.35);
  transition: transform 0.2s ease, box-shadow 0.2s ease;
}

.contact__button:hover {
  transform: translateY(-2px);
  box-shadow: 0 12px 28px rgba(124, 92, 252, 0.45);
}

/* ==========================================================================
   Footer
   ========================================================================== */
.footer {
  padding: 48px 24px 24px;
  background-color: var(--color-bg-alt);
  border-top: 1px solid var(--color-border);
}

.footer__inner {
  max-width: var(--container-width);
  margin: 0 auto;
  display: flex;
  justify-content: space-between;
  align-items: flex-start;
  gap: 24px;
  flex-wrap: wrap;
}

.footer__logo {
  font-weight: 700;
  font-size: 1.1rem;
  margin: 0 0 8px;
  color: var(--color-text);
}

.footer__creator {
  font-size: 0.85rem;
  color: var(--color-text-muted);
  margin: 0;
}

.footer__links {
  display: flex;
  gap: 24px;
  flex-wrap: wrap;
}

.footer__link {
  font-size: 0.9rem;
  color: var(--color-text-muted);
  transition: color 0.2s ease;
}

.footer__link:hover {
  color: var(--color-text);
}

.footer__copyright {
  max-width: var(--container-width);
  margin: 32px auto 0;
  text-align: center;
  font-size: 0.8rem;
  color: var(--color-text-muted);
}

/* ==========================================================================
   Responsive: tablet (<=1024px)
   ========================================================================== */
@media (max-width: 1024px) {
  .hero__title {
    font-size: 2.25rem;
  }

  .features__list {
    grid-template-columns: repeat(2, 1fr);
  }
}

/* ==========================================================================
   Responsive: mobile (<=768px)
   ========================================================================== */
@media (max-width: 768px) {
  .header__toggle {
    display: flex;
  }

  .header__nav {
    position: absolute;
    top: 100%;
    left: 0;
    right: 0;
    background-color: var(--color-bg-alt);
    border-bottom: 1px solid var(--color-border);
    max-height: 0;
    overflow: hidden;
    transition: max-height 0.3s ease;
  }

  .header__nav.is-open {
    max-height: 320px;
  }

  .header__nav-list {
    flex-direction: column;
    align-items: flex-start;
    gap: 0;
    padding: 8px 24px 24px;
  }

  .header__nav-item {
    width: 100%;
    padding: 12px 0;
    border-bottom: 1px solid var(--color-border);
  }

  .header__nav-item:last-child {
    border-bottom: none;
  }

  .header__nav-link--cta {
    display: inline-block;
  }

  .hero {
    padding: 64px 20px;
  }

  .hero__inner {
    flex-direction: column;
    text-align: center;
  }

  .hero__subtitle {
    margin-left: auto;
    margin-right: auto;
  }

  .hero__title {
    font-size: 1.9rem;
  }

  .features {
    padding: 64px 20px;
  }

  .features__list {
    grid-template-columns: 1fr;
  }

  .contact {
    padding: 64px 20px;
  }

  .contact__button {
    align-self: stretch;
    text-align: center;
  }

  .footer__inner {
    flex-direction: column;
  }
}