body {
  font-family: system-ui;
  line-height: 1.45;
  overflow: hidden;
}

* {
  box-sizing: border-box;
}

img {
  max-width: 100%;
  -o-object-fit: cover;
     object-fit: cover;
}

input {
  font-size: 16px;
}

.app-container {
  max-width: 700px;
  margin-inline: auto;
  height: 100svh;
  padding: 4.5rem 1rem 6.5rem;
  overflow-y: auto;
}

.post-header {
  position: fixed;
  top: 0;
  left: 0;
  right: 0;
  display: flex;
  padding: 1rem;
  text-align: center;
  background-color: #fff;
  box-shadow: 0 3px 10px 0 rgba(0, 0, 0, 0.1);
  border-bottom: 1px solid lightgrey;
}
.post-header p {
  flex: 1;
}
.post-header p:first-child {
  text-align: start;
}
.post-header p:last-child {
  text-align: end;
}
.post-header svg {
  --size: 1.25rem;
  width: var(--size);
  height: var(--size);
}

.post-comments {
  flex: 1;
  overflow-y-: auto;
}

.comment {
  padding: 12px;
}
.comment h3 {
  font-weight: bold;
}

.post-footer {
  position: fixed;
  left: 0;
  right: 0;
  bottom: max(48px, env(keyboard-inset-height, 0px));
  display: flex;
  gap: 0.5rem;
  padding: 1rem;
  text-align: center;
  background-color: #fff;
  box-shadow: 0 -3px 10px 0 rgba(0, 0, 0, 0.1);
  border-top: 1px solid lightgrey;
}
.post-footer input {
  width: 100%;
}

.comment:not(:last-child) {
  border-bottom: 1px solid lightgrey;
}

.nav {
  position: fixed;
  left: 0;
  right: 0;
  bottom: max(0px, env(keyboard-inset-height, 0px) - 100px);
  background: lightgrey;
}
.nav ul {
  display: flex;
}
.nav li {
  flex: 1;
  text-align: center;
  padding-block: 12px;
}
.nav span {
  display: inline-block;
  --size: 1.5rem;
  width: var(--size);
  height: var(--size);
  background-color: #fff;
  border-radius: 50%;
}