* {
    margin: 0;
    padding: 0;
    box-sizing: border-box;
    font-family: 'Segoe UI', Tahoma, Geneva, Verdana, sans-serif;
    transition: all 0.3s ease;
}

body.light-mode {
    background: linear-gradient(145deg, #4facfe, #00f2fe);
    color: #333;
}

body.dark-mode {
    background: linear-gradient(145deg, #0f2027, #203a43, #2c5364);
    color: #fff;
}

.center-container {
    display: flex;
    justify-content: center;
    align-items: center;
    min-height: 100vh;
    padding: 20px;
}

.todo-container {
    background: #00c6ff;
    padding: 40px 30px;
    border-radius: 20px;
    width: 100%;
    max-width: 380px;
    box-shadow: 0 20px 60px rgba(0,0,0,0.3);
    animation: fadeIn 0.8s ease;
}

body.dark-mode .todo-container {
    background: #1e1e2d;
    box-shadow: 0 20px 60px rgba(0,0,0,0.5);
}

h1 {
    text-align: center;
    margin-bottom: 25px;
    color: inherit;
    font-size: 22px;
}

.mode-toggle {
    text-align: center;
    margin-bottom: 20px;
}

.mode-toggle button {
    padding: 8px 15px;
    border: none;
    border-radius: 15px;
    cursor: pointer;
    background: rgba(255,255,255,0.9);
    color: #333;
    font-weight: bold;
    margin: 0 5px;
    box-shadow: 0 4px 10px rgba(0,0,0,0.2);
    transition: all 0.3s ease;
}

.mode-toggle button:hover {
    background: #fff;
    color: #0066ff;
    transform: scale(1.1);
    box-shadow: 0 8px 20px rgba(0,0,0,0.3);
}

.input-group {
    display: flex;
    gap: 10px;
    margin-bottom: 25px;
}

#inp {
    flex: 1;
    padding: 12px 15px;
    border-radius: 15px;
    border: none;
    background: rgba(255,255,255,0.9);
    font-size: 15px;
    color: #333;
    box-shadow: inset 0 2px 5px rgba(0,0,0,0.1);
    outline: none;
}

body.dark-mode #inp {
    background: #2c2c3a;
    color: #fff;
}

.input-group button {
    padding: 12px 20px;
    border-radius: 15px;
    border: none;
    background: #0066ff;
    color: #fff;
    font-weight: bold;
    cursor: pointer;
    box-shadow: 0 6px 15px rgba(0,0,0,0.3);
    transition: all 0.3s ease;
}

.input-group button:hover {
    background: #3399ff;
    transform: scale(1.05);
}

ul {
    list-style: none;
    padding: 0;
    margin: 0;
}

li {
    display: flex;
    align-items: center;
    justify-content: space-between;
    background: rgba(255,255,255,0.9);
    padding: 12px 15px;
    border-radius: 15px;
    margin-bottom: 12px;
    font-size: 16px;
    color: #333;
    transform: translateY(50px);
    opacity: 0;
    animation: slideUp 0.5s forwards;
    box-shadow: 0 4px 12px rgba(0,0,0,0.15);
}

body.dark-mode li {
    background: #2c2c3a;
    color: #fff;
    box-shadow: 0 4px 12px rgba(0,0,0,0.3);
}

li.completed span {
    text-decoration: line-through;
    color: #999;
}

li span {
    flex: 1;
    cursor: pointer;
}

li button {
    padding: 6px 10px;
    border: none;
    border-radius: 8px;
    font-size: 12px;
    cursor: pointer;
    transition: 0.3s ease;
}

.editBtn {
    background: #f1c40f;
    color: #333;
    margin-right: 5px;
}

.editBtn:hover {
    background: #f7dc6f;
}

.dltBtn {
    background: #e63946;
    color: #fff;
}

.dltBtn:hover {
    background: #ff5c5c;
}

@keyframes slideUp {
    to {
        transform: translateY(0);
        opacity: 1;
    }
}

@keyframes fadeIn {
    from {
        opacity: 0;
        transform: translateY(-10px);
    }
    to {
        opacity: 1;
        transform: translateY(0);
    }
}

@media (max-width: 450px) {
    .todo-container {
        padding: 30px 20px;
    }
    #inp, .input-group button {
        font-size: 14px;
        padding: 10px;
    }
    li {
        font-size: 14px;
        padding: 10px;
    }
}