*{
    margin:0;
    padding:0;
    box-sizing:border-box;
}

body{
    font-family:'맑은 고딕', sans-serif;
    background:#f4f4f4;
    color:#333;
}

header{
    background:#4CAF50;
    color:white;
    text-align:center;
    padding:20px;
}

header h1{
    margin-bottom:10px;
}

#todayDate{
    margin:10px 0;
    font-size:18px;
}

nav{
    background:#333;
    padding:15px;
    text-align:center;
}

nav a{
    color:white;
    text-decoration:none;
    margin:0 15px;
    font-weight:bold;
}

nav a:hover{
    color:#4CAF50;
}

section{
    width:90%;
    max-width:1200px;
    margin:40px auto;
}

h2{
    margin-bottom:15px;
}

input{
    padding:10px;
    border:1px solid #ccc;
    border-radius:8px;
    margin-right:10px;
}

button{
    background:#4CAF50;
    color:white;
    border:none;
    padding:10px 18px;
    border-radius:8px;
    cursor:pointer;
}

button:hover{
    background:#43a047;
}

#darkModeBtn{
    margin-top:10px;
}

#taskList{
    list-style:none;
}

#taskList li{
    background:white;
    padding:15px;
    margin:12px 0;

    display:flex;
    justify-content:space-between;
    align-items:center;

    border-radius:15px;

    box-shadow:0 2px 10px rgba(0,0,0,0.1);
}

.completed{
    text-decoration:line-through;
    color:gray;
}

/* 갤러리 */

.gallery{
    display:flex;
    justify-content:center;
    gap:20px;
    flex-wrap:wrap;
    margin-top:20px;
}

.gallery img{
    width:220px;
    height:150px;

    object-fit:cover;

    border-radius:15px;

    box-shadow:0 4px 10px rgba(0,0,0,0.2);

    transition:all 0.3s ease;

    cursor:pointer;
}

.gallery img:hover{
    transform:scale(1.1);

    box-shadow:0 15px 35px rgba(0,0,0,0.4);
}

/* 학습 통계 */

#stats{
    margin-top:50px;
}

#stats p{
    font-size:18px;
    margin:8px 0;
}

/* 진행률 바 */

.progress-bar{
    width:100%;
    height:25px;

    background:#ddd;

    border-radius:20px;

    overflow:hidden;

    margin-top:15px;
}

#progressFill{
    width:0%;
    height:100%;

    background:#0a980a;

    transition:0.4s;
}

/* 목표 달성 메시지 */

#successMessage{

    display:none;

    margin-top:20px;

    padding:15px;

    background:#d4edda;

    color:#155724;

    border-radius:10px;

    text-align:center;

    font-size:18px;

    font-weight:bold;
}

/* 푸터 */

footer{
    background:#333;
    color:white;
    text-align:center;
    padding:20px;
    margin-top:40px;
}

/* 다크모드 */

.dark-mode{
    background:#222;
    color:white;
}

.dark-mode section{
    color:white;
}

.dark-mode nav{
    background:#111;
}

.dark-mode #taskList li{
    background:#333;
    color:white;
}

.dark-mode footer{
    background:#111;
}

/* 반응형 */

@media(max-width:768px){

    nav a{
        display:block;
        margin:10px 0;
    }

    input{
        width:100%;
        margin-bottom:10px;
    }

    button{
        width:100%;
    }

    .gallery img{
        width:90%;
        height:auto;
    }

    #taskList li{
        flex-direction:column;
        gap:10px;
    }
}