/* ===========================
   Reset & Base
=========================== */
*, *::before, *::after {
  box-sizing: border-box;
  margin: 0;
  padding: 0;
}

html {
  scroll-behavior: smooth;
}

body {
  font-family: "Noto Sans JP", "Hiragino Kaku Gothic ProN", sans-serif;
  font-size: 16px;
  line-height: 1.8;
  color: #333;
  background-color: #fff;
}

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

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

/* ===========================
   Utility
=========================== */
.container {
  max-width: 1100px;
  margin: 0 auto;
  padding: 0 24px;
}

/* ===========================
   Button
=========================== */
.btn {
  display: inline-block;
  padding: 14px 40px;
  border-radius: 4px;
  font-size: 1rem;
  font-weight: bold;
  cursor: pointer;
  border: none;
  transition: opacity 0.2s;
}

.btn:hover {
  opacity: 0.8;
}

.btn--primary {
  background-color: #2563eb;
  color: #fff;
}

/* ===========================
   Header
=========================== */
.header {
  position: sticky;
  top: 0;
  z-index: 100;
  background-color: #fff;
  border-bottom: 1px solid #e5e7eb;
}

.header .container {
  display: flex;
  align-items: center;
  justify-content: space-between;
  height: 64px;
}

.header__logo {
  font-size: 1.25rem;
  font-weight: bold;
  color: #2563eb;
}

.header__nav {
  display: flex;
  gap: 32px;
  font-size: 0.95rem;
}

.header__nav a:hover {
  color: #2563eb;
}

/* ===========================
   Hero
=========================== */
.hero {
  background: linear-gradient(135deg, #eff6ff 0%, #dbeafe 100%);
  padding: 100px 0;
  text-align: center;
}

.hero__title {
  font-size: clamp(1.75rem, 4vw, 2.75rem);
  font-weight: bold;
  line-height: 1.4;
  margin-bottom: 24px;
}

.hero__description {
  font-size: 1.1rem;
  color: #555;
  margin-bottom: 40px;
}

/* ===========================
   Section
=========================== */
.section {
  padding: 80px 0;
}

.section--gray {
  background-color: #f9fafb;
}

.section__title {
  font-size: clamp(1.5rem, 3vw, 2rem);
  font-weight: bold;
  text-align: center;
  margin-bottom: 40px;
  position: relative;
}

.section__title::after {
  content: "";
  display: block;
  width: 48px;
  height: 3px;
  background-color: #2563eb;
  margin: 12px auto 0;
  border-radius: 2px;
}

.section__text {
  text-align: center;
  color: #555;
  max-width: 640px;
  margin: 0 auto 40px;
}

/* ===========================
   Card Grid
=========================== */
.card-grid {
  display: grid;
  grid-template-columns: repeat(auto-fit, minmax(280px, 1fr));
  gap: 24px;
}

.card {
  background-color: #fff;
  border: 1px solid #e5e7eb;
  border-radius: 8px;
  padding: 32px 24px;
  text-align: center;
}

.card__icon {
  font-size: 2rem;
  font-weight: bold;
  color: #2563eb;
  margin-bottom: 16px;
}

.card__title {
  font-size: 1.1rem;
  font-weight: bold;
  margin-bottom: 12px;
}

.card__text {
  font-size: 0.95rem;
  color: #666;
}

/* ===========================
   Form
=========================== */
.form {
  max-width: 640px;
  margin: 0 auto;
}

.form__group {
  margin-bottom: 24px;
}

.form__label {
  display: block;
  font-weight: bold;
  margin-bottom: 8px;
  font-size: 0.95rem;
}

.form__input,
.form__textarea {
  width: 100%;
  padding: 12px 16px;
  border: 1px solid #d1d5db;
  border-radius: 4px;
  font-size: 1rem;
  font-family: inherit;
  transition: border-color 0.2s;
}

.form__input:focus,
.form__textarea:focus {
  outline: none;
  border-color: #2563eb;
}

.form__textarea {
  resize: vertical;
}

.form .btn {
  width: 100%;
}

/* ===========================
   Footer
=========================== */
.footer {
  background-color: #1f2937;
  color: #9ca3af;
  padding: 32px 0;
  text-align: center;
}

.footer__copy {
  font-size: 0.875rem;
}

/* ===========================
   Responsive
=========================== */
@media (max-width: 768px) {
  .header__nav {
    gap: 20px;
    font-size: 0.85rem;
  }

  .hero {
    padding: 64px 0;
  }

  .section {
    padding: 56px 0;
  }
}