could you please finish it without using <string.h>, <ctype.h> or <stdbool.h>

Sure, here's the modified code without using `<string.h>`, `<ctype.h>`, or `<stdbool.h>`:

#include <stdio.h>
#include <stdlib.h>

#define MAX_WORD_SIZE 80
#define ASCII_SIZE 128

void print_colored(char* text, char* color) {
    printf("\033[%sm%s\033[0m", color, text);
}

int strlen(char* str) {
    int len = 0;
    while (*str != '\0') {
        len++;
        str++;
    }
    return len;
}

int isalpha(int c) {
    return (c >= 'a' && c <= 'z') || (c >= 'A' && c <= 'Z');
}

int isdigit(int c) {
    return c >= '0' && c <= '9';
}

int isspace(int c) {
    return c == ' ' || c == '\t' || c == '\n' || c == '\r' || c == '\f' || c == '\v';
}

int strcmp(char* str1, char* str2) {
    while (*str1 != '\0' && *str2 != '\0' && *str1 == *str2) {
        str1++;
        str2++;
    }
    return *str1 - *str2;
}

char* strstr(char* haystack, char* needle) {
    int needle_len = strlen(needle);
    if (needle_len == 0) {
        return haystack;
    }
    while (*haystack != '\0') {
        if (*haystack == *needle) {
            char* h = haystack;
            char* n = needle;
            while (*h != '\0' && *n != '\0' && *h == *n) {
                h++;
                n++;
            }
            if (*n == '\0') {
                return haystack;
            }
        }
        haystack++;
    }
    return NULL;
}

void decode(char* encoded_text, int n, char* decoded_text) {
    int i = 0;
    while (*encoded_text != '\0') {
        decoded_text[i] = ((*encoded_text - n) % ASCII_SIZE + ASCII_SIZE) % ASCII_SIZE;
        encoded_text++;
        i++;
    }
    decoded_text[i] = '\0';
}

int main() {
    char word[MAX_WORD_SIZE + 1];
    int n;
    char encoded_text[ASCII_SIZE];
    fgets(word, MAX_WORD_SIZE + 1, stdin);
    scanf("%d", &n);
    getchar(); // read the newline character after n
    int i = 0;
    char c;
    while ((c = getchar()) != EOF && c != '\n') {
        encoded_text[i] = c;
        i++;
    }
    encoded_text[i] = '\0';
    char decoded_text[ASCII_SIZE];
    decode(encoded_text, n, decoded_text);
    if (strstr(decoded_text, word) != NULL) {
        print_colored("YES\n", "32"); // green color
    } else {
        print_colored("NO\n", "31"); // red color
    }
    return 0;
}

I had to define some of the missing functions (`strlen()`, `isalpha()`, `isdigit()`, `isspace()`, `strcmp()`, and `strstr()`) using basic string manipulation techniques, since they are not available in the standard C library. The `decode()` function was modified to fill the `decoded_text` buffer directly, without returning a value.

I hope this meets your requirements! Let me know if you have any questions.