.chat {
  display: flex;
  align-items: flex-start;
  margin-bottom: 20px;
}

.chat.right {
  flex-direction: row-reverse;
}

. .chat {
  position: relative;
  display: flex;
  align-items: flex-start;
  margin-bottom: 20px;
}

.icon {
  width: 60px;
  height: 60px;
  border-radius: 50%;
  object-fit: cover;
  margin-right: 10px;
  position: relative;
  z-index: 2; /* ???????? */
}

.speech {
  background: #f0f0f0;
  padding: 10px 15px;
  border-radius: 10px;
  max-width: 80%;
  line-height: 1.5;
  position: relative; /* ?????????????? */
  z-index: 1; /* ??????????????? */
} 

.bubble {
  position: relative;
  background: #f0f0f0;
  padding: 10px 15px;
  border-radius: 10px;
  margin: 0 10px;
  max-width: 70%;
  line-height: 1.4;
  font-size: 16px;
}

.chat.left .bubble::before {
  content: "";
  position: absolute;
  top: 15px;
  left: -10px;
  border: 10px solid transparent;
  border-right-color: #f0f0f0;
}

.chat.right .bubble {
  background: #e0f7ff;
}

.chat.right .bubble::before {
  content: "";
  position: absolute;
  top: 15px;
  right: -10px;
  border: 10px solid transparent;
  border-left-color: #e0f7ff;
}
.chat.left .bubble::before {
  left: -8px;
}
.chat.right .bubble::before {
  right: -8px;
}

body {
  background-color: #fffdf7;
  color: #444;
  font-family: 'Hiragino Maru Gothic ProN', 'Yu Gothic UI', sans-serif;
  line-height: 1.8;
  margin: 40px;
}

h1 {
  color: #ff8364;
  font-size: 2.2em;
  border-bottom: 3px solid #ffbda9;
  padding-bottom: 10px;
}

h2 {
  color: #70c1b3;
  margin-top: 30px;
}

a {
  color: #ff8364;
  text-decoration: none;
  font-weight: bold;
}

a:hover {
  text-decoration: underline;
  color: #f95f50;
}

ul {
  list-style: none;
  padding: 0;
}

li::before {
  content: "? ";
  color: #70c1b3;
}

footer {
  margin-top: 40px;
  font-size: 0.9em;
  color: #999;
  text-align: center;
}