* { box-sizing: border-box; }
body { margin: 0; font-family: -apple-system, Segoe UI, Roboto, sans-serif; background: #f4f4f4; color: #222; }
/* Renkler bir tık canlandı: aynı düzen, daha sıcak tonlar. */
header { background: linear-gradient(135deg, #1f6f8b 0%, #2f9e8f 100%); color: #fff; padding: 12px 16px; box-shadow: 0 2px 6px rgba(0,0,0,.12); }
header h1 { margin: 0 0 8px; font-size: 20px; }
nav { display: flex; gap: 6px; }
.tab { background: rgba(255,255,255,.12); color: #eaf7f4; border: 1px solid rgba(255,255,255,.35); padding: 6px 12px; border-radius: 4px; cursor: pointer; }
.tab.active { background: #fff; color: #1f6f8b; font-weight: 600; }
main { max-width: 900px; margin: 0 auto; padding: 16px; }
.hidden { display: none !important; }
.toolbar { display: flex; gap: 8px; margin-bottom: 12px; }
.toolbar input { flex: 1; padding: 10px; font-size: 16px; border: 1px solid #ccc; border-radius: 4px; }
button { padding: 10px 14px; font-size: 15px; border: none; border-radius: 4px; background: #2a9df4; color: #fff; cursor: pointer; }
button:hover { filter: brightness(1.06); }
button.link { background: none; color: #1f87b8; padding: 0; margin-bottom: 8px; }
.summary { margin-bottom: 8px; color: #555; }
table { width: 100%; border-collapse: collapse; background: #fff; }
th, td { padding: 10px; border-bottom: 1px solid #eee; text-align: left; }
th { background: #f2f8f7; font-size: 13px; color: #4a6b66; }
td.num, th.num { text-align: right; }
#musteriTablo tbody tr { cursor: pointer; }
#musteriTablo tbody tr:hover { background: #eef8f6; }
.red { color: #d63a2f; }
.green { color: #1e9e55; }
.muted { color: #888; margin-top: 0; }
.balance { font-size: 22px; font-weight: bold; margin: 8px 0 16px; }
#islemForm { display: flex; flex-wrap: wrap; gap: 8px; margin-bottom: 16px; }
#islemForm input { flex: 1; min-width: 120px; padding: 10px; font-size: 16px; border: 1px solid #ccc; border-radius: 4px; }
button.borc { background: #d63a2f; }
button.odeme { background: #1e9e55; }
button.sil { background: #eee; color: #900; padding: 4px 8px; font-size: 12px; }
/* WhatsApp hatırlatma düğmesi — dokunma hedefi en az 44px */
td.wa-cell { text-align: right; padding: 6px; width: 1%; white-space: nowrap; }
button.wa { background: #25d366; min-height: 44px; padding: 8px 12px; font-size: 13px; white-space: nowrap; }
button.wa:active { background: #1da851; }
.cards { display: flex; gap: 12px; margin-bottom: 12px; }
.card { flex: 1; background: #fff; padding: 14px; border-radius: 6px; border-left: 4px solid #2f9e8f; box-shadow: 0 1px 4px rgba(0,0,0,.06); }
.card:nth-child(2) { border-left-color: #d63a2f; }
.card span { display: block; color: #777; font-size: 13px; }
.card strong { font-size: 22px; }
.modal { position: fixed; inset: 0; background: rgba(0,0,0,.4); display: flex; align-items: center; justify-content: center; }
.modal-box { background: #fff; padding: 20px; border-radius: 8px; width: 300px; }
.modal-box input { width: 100%; padding: 10px; font-size: 16px; margin: 8px 0; }
.modal-actions { display: flex; justify-content: flex-end; gap: 8px; }
@media (max-width: 600px) {
  header h1 { font-size: 17px; }
  th, td { padding: 8px 6px; font-size: 14px; }
}