/* 
 * =================================
 * Base Styles & Variables
 * =================================
 */
:root {
  --primary-color: #007bff;
  --secondary-color: #333;
  --accent-color: #a3683d;
  --background-color: #f8f8f8;
  --white: #fff;
  --hover-color: #e0e0e0;
  --font-family-base: 'Noto Sans JP', sans-serif;
  --logo-max-width: 80px;
}

body {
  font-family: var(--font-family-base);
  line-height: 1.6;
  margin: 0;
  background-color: var(--background-color);
  color: var(--secondary-color);
  font-size: 16px;
}

a {
  text-decoration: none;
  color: var(--secondary-color);
  font-weight: 700;
  padding: .8rem 1.2rem;
  border-radius: 5px;
  transition: background-color .3s ease, color .3s ease;
}

a:hover {
  background-color: var(--primary-color);
  color: var(--white);
}

h1, h2, h3 {
  font-weight: 700;
}

.page_title {
  font-size: 2.0em;
  line-height: 1.3;
  margin-top: 1.5rem;
  margin-bottom: 1rem;
}

/* 
 * =================================
 * Layout & Components
 * =================================
 */

/* --- Navigation --- */
.navbar {
  background-color: var(--white);
  padding: 1rem 2rem;
  box-shadow: 0 2px 4px rgba(0,0,0,0.1);
  position: sticky;
  top: 0;
  z-index: 1000;
  display: flex;
  align-items: center;
  justify-content: space-between;
}

.navbar .logo {
  width: 100px;
  height: 100px;
  border: 2px solid var(--accent-color);
  background-color: transparent;
  border-radius: 5px;
  box-shadow: 2px 2px 5px rgba(0,0,0,0.1);
}

.navbar .logo img {
  max-width: 100%;
  height: auto;
  border: 0;
}

.navbar ul {
  list-style: none;
  margin: 0;
  padding: 0;
  display: flex;
  flex-wrap: wrap;
}

.navbar li {
  margin-right: 1rem;
  position: relative;
}

/* --- Dropdown Menu --- */
.dropdown {
  position: relative;
  display: inline-block;
}

.dropdown .dropbtn {
  background-color: var(--primary-color);
  color: var(--white);
  padding: .8rem 1rem;
  font-size: 1rem;
  border: none;
  cursor: pointer;
}

.dropdown-content {
  display: none;
  position: absolute;
  background-color: var(--white);
  min-width: 200px;
  box-shadow: 0 8px 16px rgba(0,0,0,0.2);
  z-index: 1;
  padding: 1rem;
  border-radius: 5px;
}

.dropdown:hover .dropdown-content {
  display: block;
}

.dropdown-content a {
  color: var(--secondary-color);
  padding: .5rem 1rem;
  text-decoration: none;
  display: block;
  font-weight: 500;
}

.dropdown-content a:hover {
  background-color: var(--hover-color);
}

/* --- Page Top Button --- */
.pagetop {
  position: fixed;
  bottom: 1rem;
  right: 1rem;
  width: 3.3rem;
  height: 3.3rem;
  line-height: 3.3rem;
  border-radius: 50%;
  background-color: var(--accent-color);
  color: var(--white);
  text-align: center;
  font-size: 1.5rem;
  cursor: pointer;
  box-shadow: 0 2px 5px rgba(0,0,0,0.2);
  transition: background-color 0.3s;
}

.pagetop:hover {
  background-color: var(--primary-color);
}

/* 
 * =================================
 * Responsive Design
 * =================================
 */
@media (max-width: 768px) {
  .navbar {
    flex-direction: column;
    align-items: center;
  }

  .navbar .logo {
    max-width: var(--logo-max-width);
    height: auto;
    margin: 0 auto 1rem;
    display: block;
  }

  .navbar ul {
    flex-direction: column;
    align-items: center;
    width: 100%;
  }

  .navbar li {
    margin: .5rem 0;
    width: 100%;
    text-align: center;
  }

  .dropdown-content {
    position: static;
    box-shadow: none;
    border-top: 1px solid #eee;
  }
}