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

body {
    font-family: 'Segoe UI', Tahoma, Geneva, Verdana, sans-serif;
    background: linear-gradient(135deg, #667eea 0%, #764ba2 100%);
    min-height: 100vh;
    display: flex;
    align-items: center;
    justify-content: center;
    padding: 20px;
}

.container {
    background: white;
    border-radius: 20px;
    box-shadow: 0 20px 40px rgba(0, 0, 0, 0.1);
    padding: 40px;
    width: 100%;
    max-width: 500px;
    text-align: center;
}

h1 {
    color: #333;
    margin-bottom: 30px;
    font-size: 2.5rem;
    font-weight: 300;
    background: linear-gradient(135deg, #667eea, #764ba2);
    -webkit-background-clip: text;
    -webkit-text-fill-color: transparent;
    background-clip: text;
}

.input-section {
    display: flex;
    gap: 15px;
    margin-bottom: 30px;
    flex-wrap: wrap;
    justify-content: center;
}

#taskInput {
    flex: 1;
    min-width: 250px;
    padding: 15px 20px;
    border: 2px solid #e1e5e9;
    border-radius: 12px;
    font-size: 16px;
    transition: all 0.3s ease;
    outline: none;
    background: #f8f9fa;
}

#taskInput:focus {
    border-color: #667eea;
    background: white;
    box-shadow: 0 0 0 3px rgba(102, 126, 234, 0.1);
    transform: translateY(-2px);
}

#taskInput::placeholder {
    color: #adb5bd;
}

#addButton {
    padding: 15px 25px;
    background: linear-gradient(135deg, #667eea, #764ba2);
    color: white;
    border: none;
    border-radius: 12px;
    font-size: 16px;
    font-weight: 600;
    cursor: pointer;
    transition: all 0.3s ease;
    white-space: nowrap;
    box-shadow: 0 4px 15px rgba(102, 126, 234, 0.3);
}

#addButton:hover {
    transform: translateY(-2px);
    box-shadow: 0 8px 25px rgba(102, 126, 234, 0.4);
}

#addButton:active {
    transform: translateY(0);
}

.task-list {
    list-style: none;
    text-align: left;
}

.task-list li {
    background: #f8f9fa;
    margin-bottom: 12px;
    padding: 15px 20px;
    border-radius: 12px;
    border-left: 4px solid #667eea;
    transition: all 0.3s ease;
    display: flex;
    align-items: center;
    justify-content: space-between;
    box-shadow: 0 2px 8px rgba(0, 0, 0, 0.05);
}

.task-list li:hover {
    background: #e9ecef;
    transform: translateX(5px);
    box-shadow: 0 4px 15px rgba(0, 0, 0, 0.1);
}

.task-list li.completed {
    background: #d4edda;
    border-left-color: #28a745;
    opacity: 0.8;
}

.task-list li.completed span {
    text-decoration: line-through;
    color: #6c757d;
}

.task-actions {
    display: flex;
    gap: 8px;
}

.task-actions button {
    padding: 8px 12px;
    border: none;
    border-radius: 8px;
    cursor: pointer;
    font-size: 14px;
    transition: all 0.2s ease;
}

.complete-btn {
    background: #28a745;
    color: white;
}

.complete-btn:hover {
    background: #218838;
    transform: scale(1.05);
}

.delete-btn {
    background: #dc3545;
    color: white;
}

.delete-btn:hover {
    background: #c82333;
    transform: scale(1.05);
}

@media (max-width: 600px) {
    .container {
        padding: 30px 20px;
        margin: 20px;
    }
    
    h1 {
        font-size: 2rem;
    }
    
    .input-section {
        flex-direction: column;
        align-items: stretch;
    }
    
    #taskInput {
        min-width: auto;
    }
}