html, body {
  margin: 0;
  padding: 0;
  height: 100%;
  overflow-x: hidden;
}

body {
  min-height: 100vh;   /* อย่างน้อยเท่าจอ */
  background: url("../images/desktop_bg.jpg") no-repeat left center;
  background-size: cover;
  position: relative;
  overflow-x: hidden;  /* ป้องกัน scroll แนวนอน */
}


/* 🔹 Logo */
.logo-container {
  position: absolute;
  transform: translate(-50%, -50%);
  z-index: 20;
}

.logo {
  width: 30vw;
  max-width: 300px;
  height: auto;
}

/* 🔹 ปุ่ม Sign Up */
.signup {
  position: absolute;
  transform: translate(-50%, -50%);
  z-index: 10;
}

.sign-up {
  width: clamp(120px, 35vw, 500px);
  cursor: pointer;
  transition: transform 0.3s ease, box-shadow 0.3s ease;
}

/* 🔹 ปุ่ม Add Line */
.add-line-btn {
  position: absolute;
  width: 12vw;
  max-width: 340px;
  min-width: 340px;
  cursor: pointer;
  z-index: 1000;

}

.add-line-btn, .sign-up {
  filter: drop-shadow(0 15px 15px rgba(255, 255, 255, 0.4));
  transition: transform 0.3s ease, filter 0.3s ease;
}

/* hover */
.sign-up:hover {
  transform: translate(-0%, -5%);
  filter: drop-shadow(0 20px 20px rgba(255,255,255,0.6));
}

.add-line-btn:hover {
  transform: translate(-50%, -55%) scale(1.05);
  filter: drop-shadow(0 20px 20px rgba(255,255,255,0.6));
}


/* Mobile */
@media (max-width: 1024px) {
  body {
    margin: 0;
    padding: 0;
    overflow-x: hidden;
  }

  .hero {
    position: relative;
    width: 100%;
    /* height ตามอัตราส่วน background */
    height: calc(100vw * (1920 / 1080)); 
    min-height: 100vh;
    background: url("../images/mobile_bg.jpg") no-repeat center center;
    background-size: cover;
  }

  .logo-container,
  .signup,
  .add-line-btn {
    position: absolute; /* อยู่บน background */
    transform: translate(-50%, -50%);
  }

  .logo { width: 35vw; max-width: 250px; }
  .sign-up { width: 70vw; max-width: 360px; }
  .add-line-btn { width: 25vw; max-width: 180px; }
}