/* ====== RETRO / WIN XP ====== */
:root{
  --xp-blue: #3a6ea5;
  --xp-light: #e3edf9;
  --xp-border: #7aa2d6;
  --xp-gray: #ececec;
}

body{
  margin:0;
  font-family: Tahoma, Verdana, sans-serif;
  background-image: url("img/kosmos.gif");
  background-repeat: repeat;
}

/* ====== OKNO ====== */
#container{
  max-width: 1000px;
  margin: 20px auto;
  background: var(--xp-light);
  border: 3px solid var(--xp-border);
  box-shadow: 4px 4px 0 #000;
}

/* ====== HEADER ====== */
header{
  background: linear-gradient(#5b9bd5, var(--xp-blue));
  color: white;
  padding: 15px;
  font-size: 1.8em;
  text-shadow: 1px 1px #000;
}

/* ====== NAV ====== */
nav{
  background: var(--xp-gray);
  padding: 8px;
  border-bottom: 2px solid var(--xp-border);
}
nav a{
  margin-right: 15px;
  font-weight: bold;
  color: #003399;
  text-decoration: none;
}
nav a:hover{
  text-decoration: underline;
}

/* ====== MAIN ====== */
main{
  display:flex;
  gap:20px;
  padding:20px;
}

/* ====== SIDEBAR ====== */
#sidebar{
  width:220px;
  background:#fff;
  border:2px solid var(--xp-border);
  padding:10px;
}
#sidebar h3{
  margin-top:0;
}

/* ====== CONTENT ====== */
#content{
  flex:1;
  background:#fff;
  border:2px solid var(--xp-border);
  padding:15px;
}

/* ====== LISTA ====== */
ul{
  padding-left:20px;
}
li{
  margin-bottom:6px;
}
.item-controls button{
  font-size:0.8em;
  margin-left:5px;
}

/* ====== FORM ====== */
form{
  background:#f0f0f0;
  padding:10px;
  border:2px inset #999;
  margin-top:15px;
}
input, select, button{
  width:100%;
  margin-bottom:8px;
  padding:6px;
  font-family: Tahoma;
}

/* ====== FOOTER ====== */
footer{
  background: var(--xp-gray);
  text-align:center;
  padding:8px;
  font-size:0.85em;
  border-top:2px solid var(--xp-border);
}

/* ====== RESPONSYWNOŚĆ ====== */
@media(max-width:768px){
  main{
    flex-direction:column;
  }
  #sidebar{
    width:100%;
  }
}