* {
    box-sizing: border-box;
}
body {
    margin: 0;
    display: flex;
    align-items: center;
    justify-content: center;
    min-height: 100vh;
    background: linear-gradient(180deg, #4f7cc8 0%, #2a4f8f 60%, #1e355f 100%);
    padding: 20px;
    font-family: 'Segoe UI', Tahoma, Geneva, Verdana, sans-serif;
}
.container {
    width: 100%;
    max-width: 500px;
}
.todo-app {
    background: #ffffff;
    padding: 20px;
    border-radius: 18px;
    box-shadow: 0 25px 50px rgba(0, 0, 0, 0.25);
}
.todo-app h1 {
    color: #2c3e50;
    text-align: center;
    margin-bottom: 20px;
    font-size: 28px;
    font-weight: 600;
}
.input-field {
    display: flex;
    gap: 10px;
    margin-bottom: 20px;
}
.input-field input {
    flex: 1;
    padding: 15px;
    background: #f4f7fc;
    border: none;
    border-radius: 14px;
    font-size: 16px;
    color: #2c3e50;
    outline: none;
    transition: all 0.3s ease;
}
.input-field input:focus {
    background: #eef2f7;
    box-shadow: 0 0 0 3px rgba(79, 124, 200, 0.2);
}
.input-field button {
    padding: 15px 25px;
    background: linear-gradient(180deg, #3b82f6, #2563eb);
    border: none;
    border-radius: 14px;
    color: #ffffff;
    font-size: 18px;
    font-weight: 500;
    cursor: pointer;
    transition: transform 0.05s ease, box-shadow 0.05s ease;
}
.input-field button:active {
    transform: scale(0.97);
    box-shadow: inset 0 3px 6px rgba(0, 0, 0, 0.15);
}
.todo-container {
    max-height: 400px;
    overflow-y: auto;
}
.task-list {
    list-style: none;
}
.task-list li {
    background: #eef2f7;
    padding: 15px 20px;
    margin-bottom: 10px;
    border-radius: 14px;
    display: flex;
    align-items: center;
    justify-content: space-between;
    transition: all 0.05s ease;
    animation: slideIn 0.3s ease;
    color: #2c3e50;
    font-weight: 500;
}
@keyframes slideIn {
    from {
        opacity: 0;
        transform: translateX(-20px);
    }
    to {
        opacity: 1;
        transform: translateX(0);
    }
}
.task-list li:active {
    transform: scale(0.98);
}
.task-list li.completed {
    opacity: 0.6;
    text-decoration: line-through;
    color: #6c757d;
}
.task-list li span {
    flex: 1;
    cursor: pointer;
    word-break: break-word;
}
.task-list li .actions {
    display: flex;
    gap: 10px;
}
.task-list li button {
    background: #f4f7fc;
    border: none;
    cursor: pointer;
    font-size: 16px;
    padding: 8px 12px;
    border-radius: 10px;
    transition: transform 0.05s ease, box-shadow 0.05s ease;
    font-weight: 500;
}
.task-list li button:active {
    transform: scale(0.95);
    box-shadow: inset 0 2px 4px rgba(0, 0, 0, 0.1);
}
.task-list li .complete-btn {
    color: #059669;
    background: #d1fae5;
}
.task-list li .delete-btn {
    color: #dc2626;
    background: #fee2e2;
}
.todo-container::-webkit-scrollbar {
    width: 8px;
}
.todo-container::-webkit-scrollbar-track {
    background: #f4f7fc;
    border-radius: 10px;
}
.todo-container::-webkit-scrollbar-thumb {
    background: #3b82f6;
    border-radius: 10px;
}
.todo-container::-webkit-scrollbar-thumb:hover {
    background: #2563eb;
}
.task-list:empty::before {
    content: "No tasks yet. Add one above!";
    display: block;
    text-align: center;
    color: #6c757d;
    padding: 40px 20px;
    font-style: italic;
}
@media (max-width: 600px) {
    .todo-app {
        padding: 30px 20px;
    }
    
    .input-field input {
        padding: 12px 15px;
        font-size: 14px;
    }
    
    .input-field button {
        padding: 12px 20px;
    }
}