/*** Responsive Styles ***/

html {
  box-sizing: border-box;
}
*, *:before, *:after {
  box-sizing: inherit;
}

#main_body {
  margin: 0;
  padding: 0;
  background-position: bottom;
  background-repeat: repeat-x;
  min-height: 100vh;
}

#container {
  margin: 0 auto;
  width: 100%;
  max-width: 1200px; /* Maximum width for large screens */
  padding: 10px;
}

#header {
  height: auto;
  padding: 15px 0;
  position: relative;
}

#key_visual {
  position: relative;
  width: 100%;
  height: auto;
  margin: 0;
}

#slogan {
  padding: 0 0 10px 0;
}

#main_container {
  clear: both;
  margin: 10px 0;
}

/* Responsive Navigation */
#main_nav_container {
  position: relative;
  width: 100%;
  margin: 10px 0;
}

#main_nav_list {
  display: flex;
  flex-wrap: wrap;
  justify-content: center;
  margin: 0;
  padding: 0;
  list-style-type: none;
}

#main_nav_list li {
  flex: 1 0 auto;
  min-width: 100px;
  max-width: 150px;
  text-align: center;
}

#main_nav_list a {
  display: block;
  padding: 10px 5px;
  margin: 2px;
  text-align: center;
  line-height: 1.4;
}

/* Responsive Columns */
#layout_table {
  display: flex;
  flex-direction: column;
  width: 100%;
}

#left_column, #right_column {
  width: 100%;
  padding: 10px;
}

#sub_container1, #sub_container2 {
  width: 100%;
  padding: 20px 15px;
  position: relative;
}

#content_container {
  width: 100%;
  padding: 0;
  margin: 0;
  overflow: hidden;
}

#footer_text {
  width: 100%;
  padding: 20px 15px;
}

/* Content Elements */
.content table {
  width: 100%;
  overflow-x: auto;
  display: block;
}

.content th, .content td {
  padding: 8px;
}

.content button, 
.content textarea, 
.content input, 
.content fieldset {
  width: 100%;
  max-width: 500px;
}

/* Media Queries */
@media (min-width: 768px) {
  /* Tablet and Desktop Layout */
  #layout_table {
    flex-direction: row;
  }
  
  #left_column {
    width: 25%;
  }
  
  #right_column {
    width: 75%;
  }
  
  #main_nav_list {
    flex-wrap: nowrap;
  }
}

@media (min-width: 1024px) {
  /* Desktop adjustments */
  #container {
    padding: 20px;
  }
  
  #header {
    height: 100px;
  }
  
  #key_visual {
    height: 100px;
  }
  
  #main_nav_list a {
    padding: 12px 10px;
  }
}

@media (max-width: 480px) {
  /* Mobile adjustments */
  #main_nav_list li {
    min-width: 50%;
    max-width: 50%;
  }
  
  #sub_container1, 
  #sub_container2 {
    padding: 15px 10px;
  }
}

/* TV Screens (4K) */
@media (min-width: 1920px) {
  #container {
    max-width: 1600px;
  }
  
  #header {
    height: 150px;
  }
  
  #key_visual {
    height: 150px;
  }
  
  #main_nav_list a {
    padding: 20px 15px;
    font-size: 1.2em;
  }
}