:root {
  --zemin: #0e1117;
  --kart: #161b24;
  --cizgi: #262d3a;
  --yazi: #e8ebf1;
  --soluk: #9aa3b2;
  --vurgu: #6aa0ff;
  --vurgu-yazi: #0b1220;
}
* { box-sizing: border-box; }
html, body { margin: 0; min-height: 100%; }
body {
  background: var(--zemin);
  color: var(--yazi);
  font: 16px/1.5 system-ui, -apple-system, "Segoe UI", Roboto, Arial, sans-serif;
  display: grid;
  place-items: center;
  min-height: 100dvh;
  padding: 16px;
}
.kart {
  width: min(420px, 100%);
  background: var(--kart);
  border: 1px solid var(--cizgi);
  border-radius: 14px;
  padding: 32px 28px;
}
.ust-yazi { margin: 0; color: var(--vurgu); font-weight: 600; letter-spacing: .14em; text-transform: uppercase; font-size: 12px; }
h1 { margin: 4px 0 12px; font-size: 26px; }
.aciklama, .dipnot, .not { color: var(--soluk); }
.aciklama { margin: 0 0 22px; }
label { display: block; font-size: 14px; margin-bottom: 6px; }
input {
  width: 100%;
  padding: 12px 14px;
  border-radius: 10px;
  border: 1px solid var(--cizgi);
  background: var(--zemin);
  color: var(--yazi);
  font: 600 18px/1 ui-monospace, Consolas, monospace;
  letter-spacing: .08em;
  text-transform: uppercase;
}
input:focus { outline: 2px solid var(--vurgu); outline-offset: 1px; }
button {
  margin-top: 14px;
  width: 100%;
  padding: 12px;
  border: 0;
  border-radius: 10px;
  background: var(--vurgu);
  color: var(--vurgu-yazi);
  font-weight: 700;
  font-size: 16px;
  cursor: pointer;
}
button:disabled, input:disabled { opacity: .5; cursor: not-allowed; }
.dipnot { font-size: 12px; margin: 24px 0 0; border-top: 1px solid var(--cizgi); padding-top: 16px; }
.hata { margin: 12px 0 0; padding: 10px 12px; border-radius: 10px; background: #2a1414; border: 1px solid #5c2a2a; color: #ffb4b4; font-size: 14px; }
.hata[hidden] { display: none; }
input[aria-invalid="true"] { border-color: #c25050; }
input.duz { font: 16px/1.2 system-ui, -apple-system, "Segoe UI", Roboto, Arial, sans-serif; letter-spacing: normal; text-transform: none; margin-bottom: 14px; }