/* ================= RESET ================= */
*{
    margin:0;
    padding:0;
    box-sizing:border-box;
    font-family:Segoe UI, Arial, sans-serif;
    scroll-behavior:smooth;
}

/* ================= BODY ================= */
body{
    background:linear-gradient(135deg,#0f2027,#203a43,#2c5364);
    color:white;
    min-height:100vh;
    animation:fadePage 1s ease;
    line-height:1.6;
}

@keyframes fadePage{
    from{opacity:0;transform:translateY(20px);}
    to{opacity:1;transform:translateY(0);}
}

/* ================= HEADER ================= */
header{
    position:sticky;
    top:0;
    z-index:1000;
    background:rgba(0,0,0,0.55);
    backdrop-filter:blur(12px);
    padding:18px;
    text-align:center;
    box-shadow:0 2px 20px rgba(0,0,0,0.4);
}

header h1{
    letter-spacing:1px;
}

/* ================= NAV ================= */
nav{
    margin-top:10px;
}

nav a{
    color:white;
    margin:10px;
    text-decoration:none;
    font-weight:bold;
    transition:0.3s;
    position:relative;
}

nav a::after{
    content:"";
    position:absolute;
    width:0%;
    height:2px;
    background:#0000ff;
    left:0;
    bottom:-4px;
    transition:0.3s;
}

nav a:hover::after{
    width:100%;
}

nav a:hover{
    color:#00e5ff;
}

nav button{
    background:#0000ff;
    border:none;
    padding:7px 12px;
    border-radius:6px;
    cursor:pointer;
    font-weight:bold;
    transition:0.3s;
}

nav button:hover{
    transform:scale(1.05);
}

/* ================= HERO ================= */
.hero{
    text-align:center;
    padding:80px 20px;
}

.hero h2{
    font-size:32px;
    margin-bottom:10px;
}

.hero p{
    opacity:0.9;
}

/* ================= BIO CARD ================= */
.bio{
    background:rgba(0,0,255,0.12);
    padding:25px;
    margin:30px auto;
    width:320px;
    border-radius:18px;
    backdrop-filter:blur(12px);
    box-shadow:0 10px 30px rgba(0,0,0,0.4);
    transition:5s;
}

.bio:hover{
    transform:translateY(-5px);
}

/* ================= BUTTON ================= */
.buton{
    display:inline-block;
    margin-top:20px;
    background:#00e5ff;
    padding:12px 22px;
    border-radius:25px;
    text-decoration:none;
    color:black;
    font-weight:bold;
    transition:0.3s;
}

.buton:hover{
    transform:scale(1.05);
    box-shadow:0 0 15px #00e5ff;
}

/* ================= BOOK GRID ================= */
.kitaplar{
    display:grid;
    grid-template-columns:repeat(auto-fit,minmax(230px,1fr));
    gap:30px;
    padding:50px;
    max-width:1300px;
    margin:auto;
}

/* ================= BOOK CARD ================= */
.kart{
    background:white;
    color:black;
    padding:22px;
    border-radius:18px;
    text-align:center;
    transition:0.35s;
    cursor:pointer;
    position:relative;
    overflow:hidden;
}

.kart::before{
    content:"";
    position:absolute;
    top:0;
    left:0;
    width:100%;
    height:5px;
    background:linear-gradient(90deg,#ff00ff,#00bcd4);
}

.kart:hover{
    transform:translateY(-12px) scale(1.05);
    box-shadow:0 18px 35px rgba(0,0,0,0.5);
}

.kart h3{
    margin-bottom:10px;
}

.kart p{
    font-size:14px;
    opacity:0.85;
}

/* ================= PDF ICON ================= */
.pdf-icon{
    font-size:60px;
    margin-bottom:10px;
}

/* ================= BOOK DETAIL (AYNI SAYFA) ================= */
.detay{
    display:none;
    margin:30px auto;
    max-width:900px;
    background:rgba(255,255,255,0.12);
    padding:30px;
    border-radius:18px;
    backdrop-filter:blur(12px);
    animation:fadePage 0.6s;
}

.detay h2{
    margin-bottom:10px;
}

.detay button{
    margin-top:15px;
    background:#00e5ff;
    border:none;
    padding:10px 18px;
    border-radius:8px;
    cursor:pointer;
    font-weight:bold;
}

/* ================= FOOTER ================= */
footer{
    background:rgba(0,0,255,0.75);
    text-align:center;
    padding:25px;
    margin-top:40px;
    font-size:14px;
}

/* ================= DARK MODE ================= */
.dark{
    background:#0b0b0b;
    color:white;
}

.dark .kart{
    background:#1e1e1e;
    color:white;
}

.dark .kart p{
    color:#ddd;
}

.dark .bio{
    background:#1e1e1e;
}

.dark .detay{
    background:#1e1e1e;
}

.dark footer{
    background:#000;
}

/* ================= SCROLLBAR ================= */
::-webkit-scrollbar{
    width:10px;
}

::-webkit-scrollbar-track{
    background:#111;
}

::-webkit-scrollbar-thumb{
    background:#00e5ff;
    border-radius:10px;
}

/* ================= RESPONSIVE ================= */
@media(max-width:768px){

    .hero h2{
        font-size:24px;
    }

    .kitaplar{
        padding:25px;
        gap:20px;
    }

    .bio{
        width:90%;
    }
}

/* ================= LOGIN PAGE GÜNCEL ================= */
.login-page{
    display:flex;
    justify-content:center;
    align-items:center;
    height:100vh;
    background:linear-gradient(135deg,#0f2027,#203a43,#2c5364);
}

.login-box{
    background:rgba(255,255,255,0.12);
    padding:50px 40px;
    border-radius:18px;
    backdrop-filter:blur(12px);
    box-shadow:0 10px 30px rgba(0,0,0,0.4);
    text-align:center;
    width:400px;
    animation:fadePage 0.8s ease;
}

.login-box h2{
    margin-bottom:25px;
    font-size:36px;
    color:white;
}

.login-box input{
    width:100%;
    padding:18px;
    margin:15px 0;
    border:none;
    border-radius:10px;
    outline:none;
    font-size:20px;
}

.login-box button{
    width:100%;
    padding:18px;
    margin-top:20px;
    background:#00e5ff;
    border:none;
    border-radius:10px;
    font-size:20px;
    font-weight:bold;
    cursor:pointer;
    transition:0.3s;
}

.login-box button:hover{
    transform:scale(1.05);
    box-shadow:0 0 15px #00e5ff;
}

#error{
    color:#ff6b6b;
    margin-top:15px;
    font-size:18px;
}