body {
  margin: 0;
  font-family: "Sarabun", sans-serif;
  background: linear-gradient(135deg, #e0f7fa, #f1f8e9);
  color: #333;
}

/* กล่องรวมทั้งหมด */
#con {
  width: 100%;
  min-height: 100vh;
  display: flex;
  flex-direction: column;
}

/* ---------------------------
   ส่วนแถบนำทาง (Navigation)
----------------------------*/
#nav {
  background: #00796b;
  display: flex;
  justify-content: center;
  padding: 12px 0;
  box-shadow: 0 2px 4px rgba(0,0,0,0.2);
}

#nav a {
  color: white;
  text-decoration: none;
  margin: 0 20px;
  font-weight: 500;
  transition: color 0.3s, transform 0.3s;
}

#nav a:hover {
  color: #c8e6c9;
  transform: translateY(-2px);
}

/* ---------------------------
   ส่วนหัว (Header)
----------------------------*/
#hd {
  text-align: center;
  font-size: 28px;
  font-weight: bold;
  background: #004d40;
  color: white;
  padding: 25px 10px;
  letter-spacing: 1px;
  box-shadow: 0 2px 6px rgba(0,0,0,0.3);
}

/* ---------------------------
   แถบข้อความเลื่อน
----------------------------*/
#new {
  background: #80cbc4;
  color: #00332f;
  font-weight: 600;
  padding: 8px;
}

/* ---------------------------
   โครงสร้างเนื้อหาและเมนู
----------------------------*/
#main-layout {
  display: flex;
  flex-direction: row;
}

#menu {
  width: 25%;
  background: #fafafa;
  border-right: 2px solid #eee;
  padding: 10px;
}

#content {
  width: 75%;
  padding: 20px;
  background: rgba(255, 255, 255, 0.85);
}

/* ---------------------------
   กล่อง (Box)
----------------------------*/
.box {
  background: white;
  border-radius: 10px;
  box-shadow: 0 2px 8px rgba(0,0,0,0.1);
  margin-bottom: 20px;
  padding: 15px;
}

.boxc {
  background: #004d40;
  color: white;
  padding: 8px 10px;
  border-radius: 8px 8px 0 0;
  font-weight: 600;
}

.box-content {
  padding: 8px 12px;
  border-bottom: 1px solid #eee;
}

.box-content:last-child {
  border-bottom: none;
}

/* ---------------------------
   ปุ่มลิงก์ (Menu buttons)
----------------------------*/
#btn-go2 a {
  display: block;
  padding: 10px;
  background: #e0f2f1;
  border-radius: 6px;
  text-decoration: none;
  color: #004d40;
  font-weight: 500;
  transition: all 0.3s ease;
}

#btn-go2 a:hover {
  background: #b2dfdb;
  color: #00251a;
  transform: translateX(4px);
}

/* ---------------------------
   iframe (เนื้อหาหลัก)
----------------------------*/
iframe {
  border: none;
  border-radius: 8px;
  box-shadow: 0 0 10px rgba(0,0,0,0.1);
}

/* ---------------------------
   ส่วนท้าย (Footer)
----------------------------*/
#footer {
  text-align: center;
  background: #004d40;
  color: white;
  padding: 20px 0;
  margin-top: auto;
  font-size: 14px;
  box-shadow: 0 -2px 6px rgba(0,0,0,0.3);
}