/* ===== Úvodní stránka administrace učitele ===== */
.teacher-admin {
  min-height: 100vh;
  display: flex;
  align-items: center;
  justify-content: center;
  font-family: sans-serif;
  background: #f9f9f9;
  padding: 16px;
  box-sizing: border-box;
  overflow-x: hidden;
}

/* Přihlášení učitele */
.teacher-admin .login-box {
  background: #fff;
  padding: 48px;
  border: 1px solid #eee;
  border-radius: 14px;
  box-shadow: 0 8px 24px rgba(0, 0, 0, 0.06);
  width: 100%;
  max-width: 360px;
  text-align: center;
  box-sizing: border-box;
}

.teacher-admin .login-box h2 {
  margin: 0 0 20px;
  font-size: clamp(1.25rem, 4vw, 1.6rem);
  line-height: 1.3;
}

.teacher-admin .login-box input {
  width: 100%;
  max-width: 100%;
  padding: 10px 12px;
  margin-bottom: 15px;
  border-radius: 8px;
  border: 1px solid #aaa;
  box-sizing: border-box;
  font: inherit;
}

.teacher-admin .login-box button[type="submit"] {
  width: 100%;
  box-sizing: border-box;
  padding: 12px 24px;
  background: #2c87f0;
  color: #fff;
  border: none;
  border-radius: 10px;
  font-size: 16px;
  font-weight: bold;
  transition: filter 0.15s ease;
  cursor: pointer;
}

.teacher-admin .login-box button[type="submit"]:hover {
  filter: brightness(0.94);
}

.teacher-admin .login-box .error {
  color: #b00020;
  text-align: center;
  margin-top: 10px;
}

.teacher-admin .login-box .btn-logout {
  margin-top: 24px;
}

/* „Karta“ uprostřed */
.teacher-admin .container {
  text-align: center;
  padding: 40px 32px;
  background: #fff;
  border-radius: 14px;
  box-shadow: 0 8px 24px rgba(0,0,0,.06);
  border: 1px solid #eee;
  max-width: 720px;
  width: 100%;
  box-sizing: border-box;
}

/* Nadpis, uvítání */
.teacher-admin h2 {
  margin: 0 0 8px 0;
  font-size: 1.6rem;
}
.teacher-admin p.welcome {
  margin: 0 0 16px 0;
  opacity: .9;
}

/* Řádky tlačítek */
.teacher-admin .button-row {
  display: flex;
  justify-content: center;
  gap: 14px;
  margin-top: 18px;
  flex-wrap: wrap;
}

/* Tlačítka na úvodní stránce (oddělená od .btn v jiných částech) */
.teacher-admin .btn {
  display: inline-flex;
  align-items: center;
  justify-content: center;
  gap: 10px;
  padding: 12px 30px;
  background: #2c87f0;
  color: #fff;
  text-decoration: none;
  border-radius: 10px;
  font-size: 16px;
  font-weight: bold;
  border: 1px solid #2c87f0;
  box-sizing: border-box;
  max-width: 100%;
  transition: filter .15s ease, transform .02s ease;
}
.teacher-admin .btn:hover { filter: brightness(.94); }
.teacher-admin .btn:active { transform: translateY(1px); }

/* Sekundární tlačítko */
.teacher-admin .btn.secondary {
  background: #fff;
  color: #18406b;
  border-color: #cfd9e3;
}

/* Odhlášení zvlášť */
.teacher-admin .btn-logout {
  display: inline-flex;
  margin-top: 30px;
  background: #dc2626;
  border-color: #e25555;
}
.teacher-admin .btn-logout:hover { filter: brightness(.95); }

/* Ikonky FA na úvodní stránce */
.teacher-admin i { font-size: 18px; }

/* Responsivita */
@media (max-width: 560px) {
  .teacher-admin {
    padding: 12px;
    align-items: flex-start;
    padding-top: 24px;
  }

  .teacher-admin .container { padding: 28px 20px; }
  .teacher-admin .button-row { gap: 10px; }
  .teacher-admin .btn {
    display: flex;
    width: 100%;
    padding-left: 16px;
    padding-right: 16px;
  }

  .teacher-admin .btn-logout {
    display: flex;
    width: 100%;
  }

  .teacher-admin .login-box {
    padding: 28px 20px;
    max-width: 100%;
  }

  .teacher-admin .login-box .btn-logout {
    padding-left: 16px;
    padding-right: 16px;
    font-size: 15px;
  }
}