.post-container {
  display: flex;
  flex-flow: column;
  position: relative;
  max-width: 640px;
  width: 100%;
  padding: 0px 10px;
  margin-left: auto;
  margin-right: auto;
  min-height: 400px;
  background-color: #fff;
  color: #404040;
  padding-top: 20px;
  padding-left: 30px;
  padding-right: 30px;
  padding-bottom: 20px;
  border-radius: 10px;
  box-shadow: 0px 5px 15px 0px rgba(0, 0, 0, 0.2);
}

.post-container h2 {
  font-size: medium;
  text-align: center;
  margin-bottom: 20px;
  margin: 10px;
}

.caution {
  position: relative;
  margin-top: 1em;
  padding: 1.8em 1.5em 1em 1.5em;
  border: 2px solid #d02525;
  background-color: #fff;
  margin: 10px auto;
  font-size: medium;
}

.caution > div {
  position: absolute;
  top: -1.15em;
  left: -0.5em;
  padding: 0.4em 1.4em;
  border-radius: 25px;
  background-color: #d02525;
  color: #fff;
  font-size: 0.9em;
}

.caution > div::before {
  position: absolute;
  bottom: -8px;
  left: 50%;
  transform: translateX(-50%);
  width: 16px;
  height: 8px;
  background-color: #d02525;
  clip-path: polygon(0 0, 100% 0, 50% 100%);
  content: "";
}

.caution p {
  margin: 0;
}
.caution ul {
  margin: 5px auto;
  line-height: 20px;
}
.caution ul > li::before {
  content: "●";
  font-size: 0.5em;
  margin-right: 0.5em;
}

.post-container label {
  font-size: medium;
}

.post-container select,
.post-container input[type="text"],
.post-container textarea,
.post-container #post_tag {
  width: 100%;
  padding: 10px;
  margin-bottom: 10px;
  border: 1px solid #ccc;
  border-radius: 4px;
  font-size: medium;
}
.post-container #post_tag::after {
  content: "";
  clear: both;
  display: block;
}

.post-container #post_tag input[type="text"] {
  border-style: none;
}

.post-container button[type="submit"] {
  width: 100%;
  padding: 10px;
  background-color: #ffb347;
  font-size: medium;
  color: #ffffff;
  border: none;
  border-radius: 20px;
  cursor: pointer;
}

.post-container button[type="submit"]:hover {
  background-color: #fc9f1d;
}