app2.py

import streamlit as st 

# Inspect the header element, go to the "Computed" tab in styles, and find its height.
HEADER_HEIGHT = "60px"  # EXAMPLE: Adjust this (e.g., "56px", "4rem")
HEADER_SELECTOR = 'header[data-testid="stHeader"]'

# ---- SELECTOR FOR THE MAIN CONTENT AREA THAT NEEDS PADDING ----
# Target the first direct div child of the stAppViewContainer which often holds the main scrollable content 
MAIN_CONTENT_SELECTOR = 'section[data-testid="stMain"]'
#MAIN_CONTENT_SELECTOR = 'section[data-testid="stMain"] > div:nth-child(1)'
#MAIN_CONTENT_SELECTOR = 'section[data-testid="stMainBlockContainer"]'
#MAIN_CONTENT_SELECTOR = 'section[data-testid="stAppViewContainer"]'
#MAIN_CONTENT_SELECTOR = 'section[data-testid="stAppViewContainer"] > div:nth-child(1)'
# Alternative if the above doesn't work or if your content is further nested:
#MAIN_CONTENT_SELECTOR = 'section[data-testid="stAppViewContainer"] .main-content-wrapper-class'
# Or, very commonly, Streamlit wraps main content in a div with class "block-container":
#MAIN_CONTENT_SELECTOR = 'section[data-testid="stAppViewContainer"] .block-container'
#MAIN_CONTENT_SELECTOR = '.main .block-container' # A more general selector for block-container

custom_css = f"""
<style>
    /* Making the Streamlit header sticky */
    {HEADER_SELECTOR} {{
        position: -webkit-sticky !important; /* For Safari */
        position: sticky !important;
        top: 0 !important;
        z-index: 9999 !important; /* Very high z-index */
        background-color: #90EE90 !important; /* Or your app's header background color */
        /* Add a subtle shadow to make it feel more distinct when content scrolls under */
        /* box-shadow: 0 2px 4px -1px rgba(0,0,0,0.1); */
        /*.reportview-container .main .block-container{{ */
        /*    padding-top: 0rem; */
        /* }} */
    }}

    /* Adding padding to the main content area to prevent overlap with the sticky header */
    {MAIN_CONTENT_SELECTOR} {{
        padding-top: 10px !important; /* {HEADER_HEIGHT} !important; */
        /* background-color: yellow !important; */
        /* border-style: solid !important; */
        /* border-color: red !important; */
    }}

    /* Optional: If your app is set to wide mode and the header isn't spanning full width */
    /* This might be needed if the sticky positioning affects its width calculation. */
    /*
    #{HEADER_SELECTOR} {{
    #    width: 100% !important;
    #}}
    #*/
</style>
"""

# Inject CSS as early as possible in your app
st.markdown(custom_css, unsafe_allow_html=True)

# --- PAGE SETUP ---
type_text_page = st.Page(
    page="pages/type_text.py",
    title="DEMO (work in progress)",
    icon=":material/keyboard:",
    default=True,)


# --- Your Streamlit App ---
#st.logo(image="images/menu_book_60dp_75FBFD.png")
st.title("Map descriptions to SBS codes with Sentence Transformer + Reasoning")
st.subheader("Select specific Chapter for quicker results")
st.logo(image="images/menu_book_60dp_75FBFD.png")
st.sidebar.header("SBS V2.0 mapper")
st.sidebar.write("(work in progress)")
st.sidebar.text("Demo by JA-RAD")



# --- NAVIGATION SETUP ---
pg = st.navigation(pages=[type_text_page]) # WITHOUT SECTIONS
##pg = st.navigation({"Chapter_Index": [start_page], "Demo": [type_text_page, upload_file_page], "About": [about_page]}) # WITH SECTIONS
pg.run()