:root {
  --primary-bg-color: #5e88b2;
  --secondary-bg-color: #c7cdce; 
  --header-font-color: #fff;
  --shadow-color: #27303a;
  --accent-color: #f8ac56;
}

body {
  font-family: sans-serif;
  background-color: var(--primary-bg-color);
}

.header {
  font-size: 64px;
  text-align: center;
  color: var(--header-font-color);
  text-shadow: 2px 4px var(--shadow-color);
}

.calendar-container {
  display: flex;
}

.calendar-img-container {
  width: 45%;
  border: 8px solid #fff;
  box-shadow: 4px 8px var(--shadow-color);
  margin-right: 8px;
  background-color: #fff;
  aspect-ratio: 1 / 1;
}

.calendar-img-container img {
  width: 100%;
  animation: fadein 0.5s;
}

@keyframes fadein {
  from { opacity: 0; }
  to   { opacity: 1; }
}

.fadeout {
  opacity: 0;
  transition: opacity 0.2s ease-out;
}

.calendar-dates {
  flex-grow: 1;
  display: flex;
  flex-direction: column;
}

.calendar-dates-header {
  display: flex;
  justify-content: space-between;
}

.calendar-dates-header-control {
  margin-left: 16px;
  margin-right: 16px;
  background-color: transparent;
  border: none;
  cursor: pointer;
}

.calendar-dates-header-control:hover {
  text-decoration: underline;
  text-decoration-thickness: 4px;
  text-decoration-color: var(--accent-color);
}

.calendar-dates-header-control,
.calendar-month {
  text-align: center;
  font-size: 48px;
  color: var(--header-font-color);
  text-shadow: 2px 2px var(--shadow-color);
  margin-bottom: 8px;
}

.calendar-days {
  background-color: var(--secondary-bg-color);
  flex-grow: 1;
  border-collapse: collapse;
  table-layout: fixed;
  box-shadow: 4px 8px var(--shadow-color);
}

table, th, td {
  border: 2px solid var(--shadow-color);
}

td {
  vertical-align: top;
  text-align: right;
  padding: 8px;
  font-size: 24px;
}

td.active {
  position: relative;
}

td.active span {
  border-bottom: 6px solid var(--accent-color);
}

@media only screen and (max-width: 900px) {
  .calendar-container {
    flex-direction: column;
    align-items: center;
  }

  .calendar-img-container {
    width: 95%;
    margin-bottom: 24px;
  }

  .calendar-days {
    width: 100%;
  }

  .header {
    font-size: 26px;
  }

  .calendar-dates-header-control,
  .calendar-month {
    font-size: 24px;
  }
}