html, body {
  position: relative;
  height: 100%;
  margin: 0;
  padding: 0;
}

body {
  background-color: #eeeeee;
  font-family: helvetica, sans-serif;
  font-size: 16px;
  transform: translate3d(0, 0, 0);
  background: linear-gradient(135deg, skyblue 0%, darkblue 100%);
  filter: progid:DXImageTransform.Microsoft.gradient( startColorstr='#1e5799', endColorstr='#7db9e8',GradientType=1 );
  min-height: 100vh;  /* Mindesthöhe = Viewport, wächst bei Scroll */
  margin: 0;
  padding: 0;
  background: linear-gradient(...);  /* Dein Verlauf */
  background-attachment: fixed;  /* Optional: Verlauf "klebt" beim Scrollen */
  background-size: cover;  
}

.container {
  position: relative;
  width: 100%;
  max-width: 960px;
  min-height: 100%;
  margin: 0px auto;
  padding: 20px;
  box-sizing: border-box;
  display: flex;
  flex-direction: row;
  flex-wrap: wrap;
  justify-content: center;
  align-items: center;
}

.element-card {
  position: relative;
  width: 200px;
  height: 260px;
  transform-style: preserve-3d;
  transform: rotatey(0deg) translatex(0px) translatey(0px);
  transition: all 0.8s cubic-bezier(0.680, -0.550, 0.265, 1.550);
  box-shadow: 4px 4px 20px rgba(0, 0, 0, 0.4);
  margin: 10px;
  cursor: pointer;
}
.element-card:hover {
  transform: rotatey(45deg) translatex(0px) translatey(0px);
}
.element-card.open {
  width: 200px;
  height: 260px;
  transform: rotatey(-180deg) translatex(0px) translatey(0px);
}
.element-card .front-facing {
  transform: rotateY(0deg) translateZ(2px);
  position: absolute;
  line-height: 0;
  top: 0;
  left: 0;
  bottom: 0;
  right: 0;
  background-color: #ecf0f1;
  border: 2px white solid;
  border-radius: 5px;
}
.element-card .front-facing .abr {
  width: 100%;
  position: absolute;
  top: 63%;
  left: 0;
  font-size: 45px;
  margin: -35px 0 0 0;
  text-align: center;
  color: #3498db;
}
.element-card .front-facing .title {
  width: 100%;
  position: absolute;
  top: 50%;
  left: 0;
  text-transform: uppercase;
  font-size: 12px;
  margin: 35px 0 0 0;
  text-align: center;
  color: #3498db;
}
.element-card .front-facing .atomic-number {
  position: absolute;
  top: 10px;
  left: 10px;
  font-size: 22px;
  color: #2980b9;
}
.element-card .front-facing .atomic-mass {
  transform: rotate(180deg);
  position: absolute;
  bottom: 10px;
  right: 10px;
  font-size: 22px;
  color: #2980b9;
}
.element-card .back-facing {
  transform: rotateY(180deg) translateZ(0px);
  display: flex;
  flex-direction: column;
  flex-wrap: nowrap;
  justify-content: center;
  align-items: center;
  position: absolute;
  top: 0;
  left: 0;
  bottom: 0;
  right: 0;
  background-color: #ecf0f1;
  border: 2px white solid;
  border-radius: 5px;
  padding: 20px;
  text-align: center;
  overflow: hidden;
}
.element-card .back-facing p {
  font-size: 14px;
  margin: 0;
}
.element-card .back-facing img {
  background: skyblue; 
  border-radius: 50%; 
  max-width: 150px
}
.element-card .back-facing a.btn {
  display: inline-block;
  background-color: white;
  min-width: 150px
  padding: 5px 15px;
  margin: 20px 0 0 0;
  color: #eee;
  background-color: #3498db;
  text-decoration: none;
  border-radius: 3px;
}
.element-card .back-facing a.btn:hover, .element-card .back-facing a.btn:focus {
  color: #fff;
  background-color: #2980b9;
}
.element-card .front-facing p {
  margin: 0;
  padding: 0;
  line-height: 1.5;
  word-wrap: break-word;     /* Lange Wörter umbrechen */
  overflow-wrap: break-word; /* Moderne Alternative */
  hyphens: auto;             /* Auto-Hyphenation */
}

@media screen and (max-width: 500px) and (max-height: 1100px) {
  .element-card .front-facing p {
    font-size: 14px !important;  /* Kleinere Schrift */
    line-height: 1.1;
    word-break: break-all;       /* Hart umbrechen bei Bedarf */
    white-space: normal;
  }
}

/* Noch aggressiver für sehr schmale Screens (Fold Cover) */
@media screen and (max-width: 400px) {
  .element-card .front-facing {
    font-size: 12px !important;
    line-height: 1.0;
  }
  .element-card .front-facing p {
    word-break: break-word;
    hyphens: auto;
  }
}