@import url('https://fonts.googleapis.com/css?family=Open+Sans&display=swap');

* {
  box-sizing: border-box;
}

body {
  background-color: #f4f7f6; /* Light grey background */
  font-family: 'Open Sans', sans-serif;
  display: flex;
  align-items: center;
  justify-content: center;
  height: 100vh;
  margin: 0;
}

.mobile-device-frame {
  position: relative;
  overflow: hidden;
  border: 3px solid #bdc3c7; /* Light grey border */
  border-radius: 15px;
  height: 600px;
  width: 340px;
  box-shadow: 0 5px 15px rgba(0, 0, 0, 0.1); /* Subtle shadow */
}

.mobile-device-frame .content-panel {
  opacity: 0;
  object-fit: cover;
  position: absolute;
  top: 0;
  left: 0;
  height: calc(100% - 60px); /* Adjust for nav height */
  width: 100%;
  transition: opacity 0.4s ease;
}

.mobile-device-frame .content-panel.show {
  opacity: 1;
}

nav {
  position: absolute;
  bottom: 0;
  left: 0;
  width: 100%;
}

nav ul {
  background-color: #2c3e50; /* Dark blue-grey for nav */
  display: flex;
  list-style-type: none;
  padding: 0;
  margin: 0;
  height: 60px;
}

nav li {
  color: #bdc3c7; /* Light grey for inactive icons/text */
  cursor: pointer;
  flex: 1;
  padding: 10px;
  text-align: center;
  transition: color 0.3s ease;
}

nav ul li p {
  font-size: 12px;
  margin: 2px 0;
}

nav ul li:hover,
nav ul li.active {
  color: #2ecc71; /* Green for active/hover */
}

.nav-icon {
  width: 24px;
  height: 24px;
  fill: currentColor; /* Use current text color for SVG */
}