/* ===============================================
   RealHistorian Product Page Styles
   Mobile First Approach - Single breakpoint at 1200px
   =============================================== */

/* ===============================================
   Base styles (Mobile < 1200px)
   =============================================== */

/* Main content area */
main {
  margin-top: 60px;
  margin-bottom: 5rem;
}

/* Product hero section */
.product-section {
  height: 500px;
  background-image: url('../images/realhistorian-top.png');
  background-position: center center;
  background-size: cover;
  text-align: center;
  letter-spacing: 0.1em;
  color: white;
  position: relative;
}

/* Backdrop blur overlay */
.backdrop-blur {
  width: 100%;
  height: 100%;
  /* Fallback: semi-transparent background */
  background-color: rgba(0, 0, 0, 0.3);
  /* Safari/Webkit prefix */
  -webkit-backdrop-filter: blur(4px);
  backdrop-filter: blur(4px);
}

/* Content container */
.product-content {
  padding: 8rem 1rem 1rem;
  max-width: 75rem;
  margin: 0 auto;
}

.product-content-ja {
  padding: 4rem 1rem 1rem;
}

/* Brand name */
.brand-name {
  font-size: 1.25rem;
  font-weight: bold;
  font-style: italic;
}

/* Main heading */
.main-heading {
  font-size: 1.875rem;
  font-weight: bold;
  margin-bottom: 1.5rem;
}

/* Features list */
.features-list {
  font-size: 1.125rem;
  text-align: left;
  list-style-type: disc;
  padding-left: 2rem;
  padding-right: 1rem;
  margin-bottom: 1rem;
}

.features-list li {
  margin-bottom: 0.5rem;
}

/* Container section */
.container-section {
  max-width: 75rem;
  margin: 0 auto;
  margin-top: 1.5rem;
  padding: 0 16px;
}

/* Navigation bar */
.nav-bar {
  height: 3rem;
  background-color: #f1f5f9;
  color: white;
  font-size: 1rem;
  line-height: 3rem;
  position: sticky;
  top: 60px;
  z-index: 10;
  display: flex;
  align-items: center;
  justify-content: space-between;
}

/* Navigation left container */
.nav-left {
  display: flex;
  height: 100%;
}

/* Navigation items */
.nav-item {
  user-select: none;
  height: 100%;
  display: flex;
  align-items: center;
  justify-content: center;
  margin-right: 0.5rem;
  background-color: #81add3;
  cursor: pointer;
  transition: background-color 0.3s ease;
  padding: 0 1rem;
}

.nav-item.inactive {
  background-color: #999;
}

/* Download button */
.download-btn {
  border: 2px solid #7364de;
  height: 100%;
  border-radius: 0.25rem;
  padding: 0 0.75rem;
  color: #7364de;
  background-color: white;
  font-weight: bold;
  display: flex;
  align-items: center;
  justify-content: center;
  z-index: 0;
}

.download-btn a {
  color: #7364de;
  text-decoration: none;
}

.download-btn:hover {
  background-color: #f0f9ff;
}

/* Content box */
.content-box {
  margin: 3rem 16px 0;
  position: relative;
  padding-top: 1.5rem;
  padding-bottom: 1rem;
  border: 2px solid #7364de;
  border-radius: 0.25rem;
  font-size: 1rem;
}

.content-box h3 {
  position: absolute;
  top: -1.5rem;
  left: 2.25rem;
  padding: 0.5rem 1rem;
  color: white;
  font-size: 1.125rem;
  font-weight: bold;
  border-radius: 0.25rem;
  background-color: #7364de;
  letter-spacing: 0.025em;
}

.content-box ul {
  list-style-type: decimal;
  padding-left: 3rem;
  padding-right: 1rem;
}

.content-box li {
  margin-top: 0.5rem;
}

/* Detail sections */
.detail-section {
  display: none;
}

.detail-section.active {
  display: block;
}

.detail-section img {
  display: block;
  margin: 0 auto;
}

/* System structure image */
.sys-structure {
  margin: 1.5rem 0;
  padding: 0 16px;
  width: 100%;
  max-width: 1049px;
  height: auto;
}

/* Description box */
.description-box {
  position: relative;
  margin: 3rem 16px 0;
  padding-top: 1.5rem;
  padding-bottom: 1.25rem;
  border: 2px solid #7364de;
  border-radius: 0.25rem;
}

.description-box h3 {
  position: absolute;
  top: -1.5rem;
  left: 2.25rem;
  padding: 0.5rem 1rem;
  color: white;
  font-size: 1.125rem;
  font-weight: bold;
  background-color: #7364de;
  border-radius: 0.25rem;
  letter-spacing: 0.025em;
}

.description-box p {
  margin-top: 0.5rem;
  padding: 0 1rem;
  font-size: 1rem;
  text-indent: 2rem;
}

/* ===============================================
   Desktop styles (≥ 1200px)
   =============================================== */
@media (min-width: 1200px) {

  /* Main content area */
  main {
    margin-top: 60px;
  }

  /* Product hero section */
  .product-section {
    height: 600px;
  }

  /* Backdrop blur overlay - desktop */
  .backdrop-blur {
    background-color: transparent;
    -webkit-backdrop-filter: none;
    backdrop-filter: none;
  }

  .backdrop-blur-ja {
    background-color: rgba(0, 0, 0, 0.3);
    ;
    -webkit-backdrop-filter: blur(4px);
    backdrop-filter: blur(4px);
  }

  /* Content container - desktop */
  .product-content {
    padding: 20rem 1rem 1rem;
  }

  .product-content-ja {
    padding: 15rem 1rem 1rem;
  }

  /* Brand name - desktop */
  .brand-name {
    font-size: 1.875rem;
  }

  /* Main heading - desktop */
  .main-heading {
    font-size: 3.75rem;
    background: linear-gradient(to bottom, #fff, #a5d2ff);
    -webkit-background-clip: text;
    background-clip: text;
    color: transparent;
  }

  /* Features list - desktop */
  .features-list {
    font-size: 1.5rem;
    list-style-type: none;
    text-align: center;
    padding-left: 1.5rem;
    padding-right: 1.5rem;
  }

  .features-list-ja {
    text-align: left;
  }

  .features-list-ja li {
    margin-bottom: 1rem;
  }

  /* Container section - desktop */
  .container-section {
    padding: 0 16px;
  }

  /* Navigation bar - desktop */
  .nav-bar {
    font-size: 1.125rem;
    top: 60px;
  }

  /* Navigation items - desktop */
  .nav-item {
    width: 10rem;
  }

  /* Content box - desktop */
  .content-box {
    margin: 3rem 1rem 0;
  }

  .content-box ul {
    padding-left: 5rem;
  }

  /* System structure image - desktop */
  .sys-structure {
    margin: 1.5rem 0;
    padding: 0;
  }

  /* Description box - desktop */
  .description-box {
    margin: 3rem 1rem 0;
  }

  .description-box p {
    padding: 0 2.5rem;
  }

  /* Sidebar display - desktop */
  .side-bar {
    display: block;
  }

  /* Container - desktop */
  .container {
    padding: 0 2rem;
  }
}