* {
    padding: 0px;
    margin: 0px;
}
body {
    background-color: lightgreen;
}

h1 {
    letter-spacing: 1.5vw;
    font-family: 'system-ui';
    text-transform: uppercase;
    text-align: center;
}
main {
    display: flex;
    align-items: center;
    justify-content: center;
    height: 75vh;
    width: 100%;
    background-size: cover;
}
.form_class {
    width: 500px;
    padding: 40px;
    border-radius: 8px;
    background-color: white;
    font-family: 'system-ui';
    box-shadow: 5px 5px 10px rgb(0,0,0,0.3);
}
.form_div {
    text-transform: uppercase;
}
.form_div > label {
    letter-spacing: 3px;
    font-size: 1rem;
}

.field_class {
    width: 100%;
    border-radius: 6px;
    border-style: solid;
    border-width: 1px;
    padding: 5px 0px;
    text-indent: 6px;
    margin-top: 10px;
    margin-bottom: 20px;
    font-family: 'system-ui';
    font-size: 0.9rem;
    letter-spacing: 2px;
}
.submit_class {
    border-style: none;
    border-radius: 5px;
    background-color: #FFE6D4;
    padding: 8px 20px;
    font-family: 'system-ui';
    text-transform: uppercase;
    letter-spacing: .8px;
    display: block;
    margin: auto;
    margin-top: 10px;
    box-shadow: 2px 2px 5px rgb(0,0,0,0.2);
    cursor: pointer;
}

/* Modal nền mờ */
.modal {
  display: none;
  position: fixed;
  top: 0;
  left: 0;
  width: 100%;
  height: 100%;
  background: rgba(0, 0, 0, 0.5);
  justify-content: center;
  align-items: center;
}

/* Nội dung modal */
.modal-content {
  background: white;
  padding: 20px;
  border-radius: 8px;
  width: 500px;
  max-height: 95vh;
  overflow-y: auto;
  position: relative;
  margin: auto;
  margin-top: 17%;
}

.modal-body {
  position: relative;
  padding: 15px;
  text-align: center;
}
.modal-footer {
  padding: 15px;
  text-align: right;
  border-top: 1px solid #e5e5e5;
}
.modal-footer .btn + .btn {
  margin-bottom: 0;
  margin-left: 5px;
}
.modal-footer .btn-group .btn + .btn {
  margin-left: -1px;
}
.modal-footer .btn-block + .btn-block {
  margin-left: 0;
}

.btn {
  display: inline-block;
  padding: 6px 12px;
  margin-bottom: 0;
  font-size: 14px;
  font-weight: normal;
  line-height: 1.42857143;
  text-align: center;
  white-space: nowrap;
  vertical-align: middle;
  cursor: pointer;
  -webkit-user-select: none;
     -moz-user-select: none;
      -ms-user-select: none;
          user-select: none;
  background-image: none;
  border: 1px solid transparent;
  border-radius: 4px;
}

@media (max-width: 767px) {
  .modal-content {
    background: white;
    padding: 20px;
    border-radius: 8px;
    width: 95%;
    max-height: 96vh;
    overflow-y: auto;
    position: relative;
  }
}