:root {
    --primary: #4f46e5;
    --primary-dark: #4338ca;
    --success: #22c55e;
    --success-dark: #16a34a;
    --danger: #ef4444;
    --danger-dark: #dc2626;
    --dark: #111827;
    --gray: #e5e7eb;
    --light-gray: #f9fafb;
    --white: #ffffff;
    --bg-body: linear-gradient(135deg, #4f46e5, #9333ea);
    --bg-container: var(--white);
    --text-color: var(--dark);
}
* {
    margin: 0;
    padding: 0;
    box-sizing: border-box;
    font-family: Arial, sans-serif;
}
body {
    background: var(--bg-body);
    color: var(--text-color);
    display: flex;
    justify-content: center;
    align-items: flex-start;
    padding: 50px 15px;
    min-height: 100vh;
    transition: all 0.3s ease;
}
.container {
    width: 90%;
    max-width: 600px;
    background: var(--bg-container);
    padding: 25px;
    border-radius: 15px;
    box-shadow: 0 20px 40px rgba(0, 0, 0, 0.1);
    transition: background 0.3s ease, color 0.3s ease;
}
h1 {
    text-align: center;
    margin-bottom: 20px;
    color: var(--text-color);
}
.input-section {
    display: flex;
    gap: 10px;
    margin-bottom: 15px;
}
input {
    flex: 1;
    padding: 10px;
    font-size: 16px;
    border: 2px solid var(--gray);
    border-radius: 6px;
    transition: 0.3s ease, border-color 0.3s ease, background 0.3s ease, color 0.3s ease;
    background: var(--bg-container);
    color: var(--text-color);
}
input:focus {
    outline: none;
    border-color: var(--primary);
}
.btn {
    border: none;
    padding: 8px 12px;
    border-radius: 6px;
    cursor: pointer;
    color: white;
    font-weight: 500;
    transition: 0.3s ease;
}
.btn:hover {
    transform: translateY(-2px);
}
.btn-primary {
    background: var(--primary);
}
.btn-primary:hover {
    background: var(--primary-dark);
}
.btn-success {
    background: var(--success);
}
.btn-success:hover {
    background: var(--success-dark);
}
.btn-danger {
    background: var(--danger);
}
.btn-danger:hover {
    background: var(--danger-dark);
}
.btn-dark {
    background: var(--dark);
}
.info {
    display: flex;
    justify-content: space-between;
    align-items: center;
    margin-bottom: 15px;
}
ul {
    list-style: none;
}
li {
    background: var(--light-gray);
    padding: 12px;
    margin-bottom: 10px;
    border-radius: 8px;
    display: flex;
    justify-content: space-between;
    align-items: center;
    transition: all 0.3s ease;
}
li.completed span {
    text-decoration: line-through;
    opacity: 0.6;
}
li div {
    display: flex;
    gap: 5px;
}
@keyframes fadeIn {
    from {
        opacity: 0;
        transform: translateY(-20px);
    }
    to {
        opacity: 1;
        transform: translateY(0);
    }
}
@keyframes slideIn {
    from {
        opacity: 0;
        transform: translateX(-20px);
    }
    to {
        opacity: 1;
        transform: translateX(0);
    }
}
@media (max-width: 768px) {
    .container {
        width: 100%;
        padding: 20px;
    }
    .input-section {
        flex-direction: column;
    }
    .input-section .btn {
        width: 100%;
    }
    .info {
        flex-direction: column;
        gap: 10px;
        align-items: center;
    }
    li {
        flex-direction: column;
        align-items: center;
        gap: 15px;
    }
    li div {
        width: 100%;
        justify-content: space-between;
    }
    li div .btn {
        width: 48%;
    }
}