body {
  margin: 0;
  padding: 0;
  min-height: 100vh;
  color: #e7e9ff;
  background-color: #0f1225;
  display: flex;
  flex-direction: column;
}

/* Navbar */
nav {
  width: 100%;
  height: 70px;
  background-color: #0f1225;
  box-shadow: 0px 2px 5px #24294d;
  display: flex;
  align-items: center;
}
.nav_div {
  width: 100%;
  padding: 0 30px;
  display: flex;
  justify-content: space-between;
  align-items: center;
}
input[type=file]{display:none}

.btn{
  margin: 2vh 0vh;
  cursor: pointer;
  padding: 10px 20px;
  border-radius: 7px;
  color: white;
  border: none;
  font-size: 14px;
  background: linear-gradient(lightblue, rgb(88, 170, 197));
  transition: background 0.3s;
  width: auto;              
  align-self: flex-start; 
}

button {
  cursor: pointer;
  padding: 10px 20px;
  border-radius: 7px;
  color: white;
  border: none;
  font-size: 14px;
  background: linear-gradient(lightblue, rgb(88, 170, 197));
  transition: background 0.3s;
  width: auto;              
  align-self: flex-start;   
}
button:hover {
  background: linear-gradient(rgb(88, 170, 197), lightblue);
}

.checkerboard{
    background-image: linear-gradient(45deg, #555 25%, transparent 25%), 
                        linear-gradient(-45deg, #555 25%, transparent 25%), 
                        linear-gradient(45deg, transparent 75%, #555 75%), 
                        linear-gradient(-45deg, transparent 75%, #555 75%);
      background-size: 20px 20px;
      background-position: 0 0, 0 10px, 10px -10px, -10px 0px;
      border-radius:10px;
      position:absolute;
      inset:0;
      z-index:0;
}

.buttons {
  display: flex;
  flex-direction: column;
  gap: 10px;
  margin-top: 20px;
  align-items: flex-start;  /* no stretching */
}

/* Main Layout */
main {
  flex: 1;
  display: grid;
  grid-template-columns: 1fr 2fr 1fr;
  gap: 15px;
  padding: 15px;
}
.card {
  padding: 20px;
  border-radius: 10px;
  background: linear-gradient(180deg, #1b1f3a, #14172e);
  display: flex;
  flex-direction: column;
}
.card {
  position: relative;          /* parent must be relative */
  padding: 20px;
  border-radius: 10px;
  background: linear-gradient(180deg, #1b1f3a, #14172e);
  display: flex;
  flex-direction: column;
  /* overflow: hidden;            prevent checkerboard overflow */
}


.checkerboard {
  background-image: 
      linear-gradient(45deg, #555 25%, transparent 25%), 
      linear-gradient(-45deg, #555 25%, transparent 25%), 
      linear-gradient(45deg, transparent 75%, #555 75%), 
      linear-gradient(-45deg, transparent 75%, #555 75%);
  background-size: 20px 20px;
  background-position: 0 0, 0 10px, 10px -10px, -10px 0px;
  border-radius: 10px;
  position: absolute;
  inset: 0;
  z-index: 0;                  /* stays behind content */
}

.card_data {
  position: relative;           /* content sits above checkerboard */
  z-index: 1;
  display: flex;
  flex-direction: column;
  gap: 15px;
}

#canvas{
  position: relative;
  z-index: 1;                 /* above checkerboard */
  display: block;
  margin: auto;               /* centers horizontally */
  width: auto;
  height: auto;
  max-width: 100%;            /* shrink on smaller screens */
  max-height: 100%;           /* keep inside parent card */
  object-fit: contain;  
}



.status_bar {
  width: 100%;
  height: 6px;
  border-radius: 5px;
  background-color: #e7e9ff;
  margin-top: -20px;
}

/* Responsive */
@media (max-width: 600px) {
  main {
    grid-template-columns: 1fr;
  }
  .buttons {
    flex-direction: row;
    flex-wrap: wrap;
    justify-content: flex-start;
  }
}