@import url('https://fonts.googleapis.com/css2?family=Inter:wght@400;500;600;700&display=swap');

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

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

.container {
    background: rgba(255, 255, 255, 0.95);
    backdrop-filter: blur(10px);
    border-radius: 24px;
    padding: 40px;
    width: 100%;
    max-width: 600px;
    box-shadow: 0 20px 60px rgba(0, 0, 0, 0.3);
}

header h1 {
    color: #2d3748;
    font-size: 2.5rem;
    font-weight: 700;
    margin-bottom: 30px;
    text-align: center;
    background: linear-gradient(135deg, #667eea 0%, #764ba2 100%);
    -webkit-background-clip: text;
    -webkit-text-fill-color: transparent;
    background-clip: text;
}

.add-todo {
    display: flex;
    gap: 12px;
    margin-bottom: 24px;
}

#todoInput {
    flex: 1;
    padding: 16px 20px;
    border: 2px solid #e2e8f0;
    border-radius: 12px;
    font-size: 16px;
    font-family: inherit;
    transition: all 0.3s ease;
    background: white;
}

#todoInput:focus {
    outline: none;
    border-color: #667eea;
    box-shadow: 0 0 0 3px rgba(102, 126, 234, 0.1);
}

#addBtn {
    padding: 16px 32px;
    background: linear-gradient(135deg, #667eea 0%, #764ba2 100%);
    color: white;
    border: none;
    border-radius: 12px;
    font-size: 16px;
    font-weight: 600;
    cursor: pointer;
    transition: all 0.3s ease;
    box-shadow: 0 4px 15px rgba(102, 126, 234, 0.4);
}

#addBtn:hover {
    transform: translateY(-2px);
    box-shadow: 0 6px 20px rgba(102, 126, 234, 0.6);
}

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

.stats {
    display: flex;
    justify-content: space-between;
    padding: 16px 20px;
    background: linear-gradient(135deg, #f7fafc 0%, #edf2f7 100%);
    border-radius: 12px;
    margin-bottom: 20px;
    font-size: 14px;
    font-weight: 600;
    color: #4a5568;
}

.todo-list {
    list-style: none;
    max-height: 400px;
    overflow-y: auto;
}

.todo-list::-webkit-scrollbar {
    width: 8px;
}

.todo-list::-webkit-scrollbar-track {
    background: #f1f1f1;
    border-radius: 10px;
}

.todo-list::-webkit-scrollbar-thumb {
    background: #667eea;
    border-radius: 10px;
}

.todo-item {
    display: flex;
    align-items: center;
    gap: 12px;
    padding: 16px 20px;
    background: white;
    border: 2px solid #e2e8f0;
    border-radius: 12px;
    margin-bottom: 12px;
    transition: all 0.3s ease;
    animation: slideIn 0.3s ease;
}

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

.todo-item:hover {
    border-color: #667eea;
    box-shadow: 0 4px 12px rgba(102, 126, 234, 0.15);
}

.todo-item.completed {
    opacity: 0.6;
    background: #f7fafc;
}

.todo-item input[type="checkbox"] {
    width: 24px;
    height: 24px;
    cursor: pointer;
    accent-color: #667eea;
}

.todo-text {
    flex: 1;
    font-size: 16px;
    color: #2d3748;
    transition: all 0.3s ease;
}

.todo-item.completed .todo-text {
    text-decoration: line-through;
    color: #a0aec0;
}

.delete-btn {
    padding: 8px 16px;
    background: linear-gradient(135deg, #fc8181 0%, #f56565 100%);
    color: white;
    border: none;
    border-radius: 8px;
    font-size: 14px;
    font-weight: 600;
    cursor: pointer;
    transition: all 0.3s ease;
    opacity: 0;
}

.todo-item:hover .delete-btn {
    opacity: 1;
}

.delete-btn:hover {
    transform: scale(1.05);
    box-shadow: 0 4px 12px rgba(245, 101, 101, 0.4);
}

.empty-state {
    text-align: center;
    padding: 60px 20px;
    color: #a0aec0;
    font-size: 18px;
}

.empty-state::before {
    content: "✨";
    display: block;
    font-size: 48px;
    margin-bottom: 16px;
}

@media (max-width: 640px) {
    .container {
        padding: 24px;
    }
    
    header h1 {
        font-size: 2rem;
    }
    
    .add-todo {
        flex-direction: column;
    }
    
    #addBtn {
        width: 100%;
    }
}