reminder/app/static/css/style.css

body {
  background-color: #EEEEEE;
  font-family: sans-serif;
  text-align: center;
  margin: 0px;
}

main {
  padding: 12px;
}

h1 {
  font-size: 1.25em;
}

label {
  text-align: left;
}

ol {
  text-align: left;
}

a:link,
a:visited {
  text-decoration: none;
  color: #0066cc;
}

a:hover,
a:active {
  text-decoration: underline;
  color: #0066cc;
}

div.form {
  width: 420px;
  margin: 0 auto;
}

div.form-group {
  display: flex;
  justify-content: space-between;
  margin-bottom: 24px;
}

div.form label {
  font-size: 18px;
}

div.form input[type="number"] {
  width: 80px;
}

footer {
  width: 100vw;
  position: absolute;
  bottom: 0px;
  padding: 10px 0px;
}

input[type="submit"] {
  width: 150px;
  color: white;
  background-color: #0066cc;
  padding: 14px 20px;
  margin: 18px;
  border: none;
  border-radius: 4px;
  cursor: pointer;
  font-weight: bold;
  font-size: 18px;
}

input[type="submit"]:hover {
  background-color: #0044aa;
}

.file {
  position: relative;
  display: inline-block;
  cursor: pointer;
  height: 2.5rem;
  width: 100%;
  margin-bottom: 16px;
}

.file input {
  min-width: 14rem;
  margin: 0;
  filter: alpha(opacity=0);
  opacity: 0;
}
.file-custom::before {
  position: absolute;
  top: -.075rem;
  right: -.075rem;
  bottom: -.075rem;
  z-index: 6;
  display: block;
  content: "Browse";
  height: 2.5rem;
  padding: .5rem 1rem;
  line-height: 1.5;
  color: #555;
  background-color: #eee;
  border: .075rem solid #ddd;
  border-radius: 0 .25rem .25rem 0;
}

.file-custom {
  position: absolute;
  top: 0;
  right: 0;
  left: 0;
  z-index: 5;
  height: 2.5rem;
  padding: .5rem 1rem;
  line-height: 1.5;
  color: #555;
  background-color: #fff;
  border: .075rem solid #ddd;
  border-radius: .25rem;
  box-shadow: inset 0 .2rem .4rem rgba(0,0,0,.05);
  -webkit-user-select: none;
  -moz-user-select: none;
  -ms-user-select: none;
  user-select: none;
}

*, ::before, ::after {
  -webkit-box-sizing: border-box;
  -moz-box-sizing: border-box;
  box-sizing: border-box;
}
.file-custom::after {
  content: attr(data-content);
}

div.error {
  color: #721c24;
  background-color: #f8d7da;
  padding: .75rem 1.25rem;
  border: 1px solid #f5c6cb;
  border-radius: .25rem;
}

@media all and (max-width: 500px) {
  div.form {
    width: 100%;
    margin: 0 auto;
  }
}