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

body {
    font-family: -apple-system, BlinkMacSystemFont, 'Segoe UI', Roboto, Oxygen, Ubuntu, Cantarell, sans-serif;
    background: linear-gradient(135deg, #3A0CA3 0%, #7209B7 50%, #4361EE 100%);
    min-height: 100vh;
    display: flex;
    justify-content: center;
    align-items: center;
    padding: 20px;
}

.container {
    background: white;
    border-radius: 20px;
    box-shadow: 0 20px 60px rgba(0, 0, 0, 0.3);
    width: 100%;
    max-width: 600px;
    padding: 40px;
    animation: slideUp 0.5s ease-out;
}

@media (max-width: 600px) {
    .container {
        padding: 20px;
        border-radius: 15px;
        margin: 10px;
    }
    
    h1 {
        font-size: 2rem;
    }
    
    .input-section {
        flex-direction: column;
    }
    
    .add-btn {
        width: 100%;
        margin-top: 10px;
    }
}

@keyframes slideUp {
    from {
        opacity: 0;
        transform: translateY(30px);
    }
    to {
        opacity: 1;
        transform: translateY(0);
    }
}

header {
    text-align: center;
    margin-bottom: 30px;
}

h1 {
    color: #333;
    font-size: 2.5rem;
    margin-bottom: 8px;
    font-weight: 700;
}

.subtitle {
    color: #666;
    font-size: 0.95rem;
}

.input-section {
    display: flex;
    gap: 10px;
    margin-bottom: 20px;
}

#todoInput {
    flex: 1;
    padding: 15px 20px;
    border: 2px solid #e0e0e0;
    border-radius: 12px;
    font-size: 1rem;
    transition: all 0.3s ease;
    outline: none;
}

#todoInput:focus {
    border-color: #4361EE;
    box-shadow: 0 0 0 3px rgba(67, 97, 238, 0.1);
}

.add-btn {
    padding: 15px 30px;
    background: linear-gradient(135deg, #7209B7 0%, #4361EE 100%);
    color: white;
    border: none;
    border-radius: 12px;
    font-size: 1rem;
    font-weight: 600;
    cursor: pointer;
    transition: all 0.3s ease;
    white-space: nowrap;
}

.add-btn:hover {
    transform: translateY(-2px);
    box-shadow: 0 5px 15px rgba(114, 9, 183, 0.4);
}

.add-btn:active {
    transform: translateY(0);
}

.stats {
    text-align: center;
    color: #666;
    font-size: 0.9rem;
    margin-bottom: 20px;
    padding: 10px;
    background: #f8f9fa;
    border-radius: 10px;
}

.separator {
    margin: 0 10px;
    color: #ccc;
}

.todo-list {
    list-style: none;
    margin-bottom: 20px;
}

.todo-item {
    background: #f8f9fa;
    padding: 15px 20px;
    margin-bottom: 10px;
    border-radius: 12px;
    display: flex;
    align-items: center;
    gap: 15px;
    animation: slideIn 0.3s ease-out;
    transition: all 0.3s ease;
}

@keyframes slideIn {
    from {
        opacity: 0;
        transform: translateX(-20px);
    }
    to {
        opacity: 1;
        transform: translateX(0);
    }
}

.todo-item:hover {
    background: rgba(76, 201, 240, 0.1);
    transform: translateX(5px);
}

.todo-item.completed {
    opacity: 0.6;
}

.todo-item.completed .todo-text {
    text-decoration: line-through;
    color: #999;
}

.checkbox {
    width: 24px;
    height: 24px;
    cursor: pointer;
    accent-color: #4CC9F0;
}

.todo-text {
    flex: 1;
    font-size: 1rem;
    color: #333;
    word-break: break-word;
}

.delete-btn {
    background: #F72585;
    color: white;
    border: none;
    border-radius: 8px;
    padding: 8px 15px;
    cursor: pointer;
    font-size: 0.9rem;
    transition: all 0.3s ease;
    opacity: 0.9;
}

.delete-btn:hover {
    opacity: 1;
    transform: scale(1.05);
}

.empty-state {
    text-align: center;
    padding: 40px 20px;
    color: #999;
    display: none;
}

.empty-state.show {
    display: block;
}

.todo-list:not(:empty) + .empty-state {
    display: none;
}