html, body { margin: 0; min-height: 100%; }
body {
  background: #008080;
  color: #000;
  font-family: Tahoma, Verdana, "Segoe UI", system-ui, sans-serif;
  display: flex;
  flex-direction: column;
  align-items: center;
  justify-content: center;
  min-height: 100vh;
  min-height: 100dvh;
  box-sizing: border-box;
  padding: 24px 12px;
}
main { display: flex; flex-direction: column; align-items: center; width: 100%; max-width: 980px; }

/* The Office Assistant's balloon. */
.balloon {
  position: relative;
  box-sizing: border-box;
  width: min(400px, 100%);
  background: #ffffe1;
  border: 1px solid #000;
  border-radius: 10px;
  padding: 18px 22px;
  box-shadow: 3px 3px 0 rgba(0, 0, 0, .25);
  font-size: 17px;
  line-height: 1.4;
}
.balloon h1 { font-size: 22px; line-height: 1.25; margin: 0 0 10px; }
.balloon p { margin: 0 0 10px; }
.balloon p:last-child { margin-bottom: 0; }
.balloon a { color: #00e; }
.balloon .option::before { content: "\25C9\00A0"; color: #000; }
/* The tail: a black triangle with a yellow one inside it. Phones: down, towards Clippy. */
.balloon::before, .balloon::after { content: ""; position: absolute; border-style: solid; }
.balloon::before { left: 24%; bottom: -22px; border-width: 22px 14px 0 0; border-color: #000 transparent transparent transparent; }
.balloon::after  { left: calc(24% + 1px); bottom: -20px; border-width: 20px 12px 0 0; border-color: #ffffe1 transparent transparent transparent; }

.clippy { display: block; margin-top: 8px; width: min(561px, 100%); }
.clippy img { display: block; width: 100%; height: auto; }

/* Wide screens: the balloon to his left, its tail pointing at his eyes. */
@media (min-width: 900px) {
  main { flex-direction: row; justify-content: center; }
  .balloon { width: 360px; margin-right: 18px; margin-top: 60px; }
  .balloon::before { left: auto; right: -24px; bottom: auto; top: 52%; border-width: 0 0 16px 24px; border-color: transparent transparent transparent #000; }
  .balloon::after  { left: auto; right: -21px; bottom: auto; top: calc(52% + 1px); border-width: 0 0 14px 21px; border-color: transparent transparent transparent #ffffe1; }
  .clippy { margin-top: 0; }
}

footer { margin-top: 18px; color: #cfe; font-size: 12px; text-align: center; }