Upload app.py

app.py

@@ -1,271 +1,235 @@
-# ── Imports ── (ORDER MATTERS: re must come after sympy wildcard)
+# ═══════════════════════════════════════════════════════════════════
+# SAAD AI ACADEMY — BSc Mathematics Solver
+# Engine: Groq (free) + SymPy (verified computation)
+# ═══════════════════════════════════════════════════════════════════
+
+# ── Imports (order matters: stdlib/third-party before sympy, re LAST) ──
 import streamlit as st
-import sympy as sp
 import os
 import requests
+import sympy as sp
 from sympy import (
-    symbols, diff, integrate, limit, solve, simplify, expand, factor,
-    latex, sympify, oo, sin, cos, tan, exp, log, sqrt, pi, E,
-    Matrix, Symbol, Function, dsolve, Eq,
-    series, Sum, Product, Rational, Integer, Float, Abs
+    symbols, diff, integrate, limit, solve,
+    sympify, oo, sin, cos, tan, exp, log, sqrt, pi, E,
+    Matrix, Symbol, Function, dsolve, Eq
 )
 from sympy.parsing.sympy_parser import (
     parse_expr,
     standard_transformations,
     implicit_multiplication_application
 )
-import re  # MUST be last — sympy wildcard would overwrite it otherwise
+import re  # MUST be last — 'from sympy import *' would overwrite re otherwise
 
-# ─── Page Config ───────────────────────────────────────────────────────────────
+# ── Page config ──────────────────────────────────────────────────────
 st.set_page_config(
     page_title="SAAD AI ACADEMY",
     page_icon="📐",
-    layout="wide",
+    layout="centered",
     initial_sidebar_state="expanded"
 )
 
-# ─── CSS Styling ───────────────────────────────────────────────────────────────
+# ── CSS — ChatGPT-style, compact font, clean dark theme ─────────────
 st.markdown("""
 <style>
-@import url('https://fonts.googleapis.com/css2?family=Rajdhani:wght@400;600;700&family=JetBrains+Mono:wght@400;500&family=Nunito:wght@300;400;600&display=swap');
-
-:root {
-    --bg:        #060b14;
-    --surface:   #0d1526;
-    --card:      #111d35;
-    --border:    #1e3058;
-    --accent:    #38bdf8;
-    --accent2:   #818cf8;
-    --gold:      #f59e0b;
-    --green:     #34d399;
-    --text:      #e2e8f0;
-    --muted:     #64748b;
-}
+@import url('https://fonts.googleapis.com/css2?family=Inter:wght@300;400;500;600&family=JetBrains+Mono:wght@400;500&display=swap');
 
+/* ── Base ── */
 html, body, [class*="css"] {
-    background-color: var(--bg);
-    color: var(--text);
-    font-family: 'Nunito', sans-serif;
+    font-family: 'Inter', sans-serif !important;
+    font-size: 14px !important;
+    background-color: #0f0f0f !important;
+    color: #ececec !important;
+}
+.block-container {
+    max-width: 780px !important;
+    padding: 1rem 1.5rem 2rem 1.5rem !important;
 }
-
 #MainMenu, footer, header { visibility: hidden; }
-.block-container { padding: 1.5rem 2rem 2rem 2rem; max-width: 1100px; }
-
-.hero {
-    background: linear-gradient(135deg, #0d1526 0%, #0f1f40 50%, #091428 100%);
-    border: 1px solid var(--border);
-    border-radius: 16px;
-    padding: 2rem 2.5rem;
-    margin-bottom: 1.5rem;
-    position: relative;
-    overflow: hidden;
+
+/* ── Header ── */
+.saad-header {
+    text-align: center;
+    padding: 1.2rem 0 0.5rem 0;
+    margin-bottom: 0.5rem;
 }
-.hero::before {
-    content: "";
-    position: absolute;
-    top: -60px; right: -60px;
-    width: 220px; height: 220px;
-    background: radial-gradient(circle, rgba(56,189,248,0.12) 0%, transparent 70%);
-    border-radius: 50%;
+.saad-header h1 {
+    font-size: 1.5rem !important;
+    font-weight: 600;
+    color: #ffffff;
+    margin: 0;
+    letter-spacing: 0.5px;
 }
-.hero-title {
-    font-family: 'Rajdhani', sans-serif;
-    font-size: 2.4rem;
-    font-weight: 700;
-    background: linear-gradient(90deg, var(--accent), var(--accent2));
-    -webkit-background-clip: text;
-    -webkit-text-fill-color: transparent;
-    margin: 0 0 0.3rem 0;
-    letter-spacing: 2px;
+.saad-header p {
+    font-size: 0.78rem;
+    color: #666;
+    margin: 0.2rem 0 0 0;
 }
-.hero-sub {
-    color: var(--muted);
-    font-size: 0.95rem;
-    letter-spacing: 1px;
-    text-transform: uppercase;
+.badge-row {
+    display: flex;
+    gap: 0.4rem;
+    justify-content: center;
+    flex-wrap: wrap;
+    margin-top: 0.6rem;
 }
-.badge-row { display: flex; gap: 0.5rem; flex-wrap: wrap; margin-top: 1rem; }
 .badge {
-    background: rgba(56,189,248,0.08);
-    border: 1px solid rgba(56,189,248,0.25);
-    color: var(--accent);
-    padding: 3px 10px;
+    background: #1a1a1a;
+    border: 1px solid #2a2a2a;
+    color: #888;
+    padding: 2px 8px;
     border-radius: 20px;
-    font-size: 0.72rem;
+    font-size: 0.68rem;
     font-family: 'JetBrains Mono', monospace;
-    letter-spacing: 0.5px;
 }
 
-.chat-area {
-    background: var(--surface);
-    border: 1px solid var(--border);
-    border-radius: 14px;
-    padding: 1.2rem 1.5rem;
-    min-height: 420px;
-    max-height: 560px;
-    overflow-y: auto;
-    margin-bottom: 1rem;
+/* ── Chat messages — override Streamlit defaults ── */
+[data-testid="stChatMessage"] {
+    background: transparent !important;
+    border: none !important;
+    padding: 0.3rem 0 !important;
+    margin: 0 !important;
+    gap: 0.6rem !important;
 }
 
-.msg-user {
-    display: flex;
-    justify-content: flex-end;
-    margin: 0.8rem 0;
+/* User message */
+[data-testid="stChatMessage"]:has([data-testid="chatAvatarIcon-user"]) {
+    flex-direction: row-reverse !important;
 }
-.msg-user .bubble {
-    background: linear-gradient(135deg, #1e3a5f, #1a2f50);
-    border: 1px solid rgba(56,189,248,0.3);
-    color: var(--text);
-    padding: 0.75rem 1.1rem;
-    border-radius: 14px 4px 14px 14px;
-    max-width: 75%;
-    font-size: 0.92rem;
-    line-height: 1.6;
-}
-.msg-ai {
-    display: flex;
-    justify-content: flex-start;
-    margin: 0.8rem 0;
-    gap: 0.6rem;
-    align-items: flex-start;
-}
-.ai-avatar {
-    width: 34px; height: 34px;
-    background: linear-gradient(135deg, var(--accent), var(--accent2));
-    border-radius: 50%;
-    display: flex; align-items: center; justify-content: center;
-    font-size: 0.9rem;
-    flex-shrink: 0;
-    color: #fff;
+[data-testid="stChatMessage"]:has([data-testid="chatAvatarIcon-user"])
+    [data-testid="stChatMessageContent"] {
+    background: #1e3a5f !important;
+    border: 1px solid #2a4a7f !important;
+    border-radius: 18px 4px 18px 18px !important;
+    padding: 0.6rem 0.9rem !important;
+    max-width: 80% !important;
+    font-size: 0.88rem !important;
+    color: #e2e8f0 !important;
 }
-.msg-ai .bubble {
-    background: var(--card);
-    border: 1px solid var(--border);
-    color: var(--text);
-    padding: 0.85rem 1.2rem;
-    border-radius: 4px 14px 14px 14px;
-    max-width: 82%;
-    font-size: 0.92rem;
-    line-height: 1.7;
+
+/* Assistant message */
+[data-testid="stChatMessage"]:has([data-testid="chatAvatarIcon-assistant"])
+    [data-testid="stChatMessageContent"] {
+    background: #1a1a1a !important;
+    border: 1px solid #2a2a2a !important;
+    border-radius: 4px 18px 18px 18px !important;
+    padding: 0.7rem 1rem !important;
+    font-size: 0.88rem !important;
+    line-height: 1.75 !important;
+    color: #ececec !important;
 }
 
-.stTextInput > div > div > input {
-    background: var(--card) !important;
-    border: 1px solid var(--border) !important;
-    border-radius: 10px !important;
-    color: var(--text) !important;
-    font-family: 'Nunito', sans-serif !important;
-    font-size: 0.95rem !important;
-    padding: 0.75rem 1rem !important;
+/* Math display blocks */
+.katex-display {
+    background: #161616 !important;
+    border-left: 3px solid #3b82f6 !important;
+    border-radius: 0 6px 6px 0 !important;
+    padding: 0.5rem 1rem !important;
+    margin: 0.4rem 0 !important;
+    overflow-x: auto !important;
 }
-.stTextInput > div > div > input:focus {
-    border-color: var(--accent) !important;
-    box-shadow: 0 0 0 2px rgba(56,189,248,0.15) !important;
+.katex { font-size: 1em !important; }
+
+/* Step labels bold + colored */
+[data-testid="stChatMessageContent"] p {
+    margin: 0.2rem 0 !important;
+    font-size: 0.88rem !important;
+    line-height: 1.75 !important;
 }
 
-.stButton > button {
-    background: linear-gradient(135deg, #1e4080, #1a3060) !important;
-    border: 1px solid var(--accent) !important;
-    color: var(--accent) !important;
-    border-radius: 10px !important;
-    font-family: 'Rajdhani', sans-serif !important;
-    font-weight: 600 !important;
-    letter-spacing: 1px !important;
-    padding: 0.5rem 1.5rem !important;
-    transition: all 0.2s !important;
+/* ── Input box ── */
+[data-testid="stChatInput"] {
+    background: #1a1a1a !important;
+    border: 1px solid #2a2a2a !important;
+    border-radius: 12px !important;
 }
-.stButton > button:hover {
-    background: linear-gradient(135deg, #2a50a0, #2040a0) !important;
-    transform: translateY(-1px) !important;
-    box-shadow: 0 4px 15px rgba(56,189,248,0.2) !important;
+[data-testid="stChatInput"] textarea {
+    font-size: 0.88rem !important;
+    color: #ececec !important;
+    background: transparent !important;
 }
 
+/* ── Sidebar ── */
 [data-testid="stSidebar"] {
-    background: var(--surface) !important;
-    border-right: 1px solid var(--border) !important;
+    background: #0a0a0a !important;
+    border-right: 1px solid #1a1a1a !important;
 }
-[data-testid="stSidebar"] .stMarkdown h3 {
-    font-family: 'Rajdhani', sans-serif;
-    color: var(--accent);
-    letter-spacing: 1px;
+[data-testid="stSidebar"] * {
+    font-size: 0.82rem !important;
 }
 
-.topic-pill {
-    background: rgba(129,140,248,0.08);
-    border: 1px solid rgba(129,140,248,0.2);
-    color: var(--accent2);
-    padding: 4px 12px;
-    border-radius: 20px;
-    font-size: 0.78rem;
-    margin: 3px 2px;
-    display: inline-block;
-    font-family: 'JetBrains Mono', monospace;
+/* ── Buttons ── */
+.stButton > button {
+    background: #1a1a1a !important;
+    border: 1px solid #2a2a2a !important;
+    color: #888 !important;
+    border-radius: 8px !important;
+    font-size: 0.78rem !important;
+    padding: 0.3rem 0.8rem !important;
+    width: 100% !important;
+    text-align: left !important;
+    transition: all 0.15s !important;
+}
+.stButton > button:hover {
+    border-color: #3b82f6 !important;
+    color: #ececec !important;
+    background: #161b2e !important;
 }
 
-::-webkit-scrollbar { width: 6px; }
-::-webkit-scrollbar-track { background: var(--surface); }
-::-webkit-scrollbar-thumb { background: var(--border); border-radius: 3px; }
-::-webkit-scrollbar-thumb:hover { background: var(--muted); }
+/* ── Spinner ── */
+.stSpinner > div { border-top-color: #3b82f6 !important; }
 
-.stSelectbox > div > div {
-    background: var(--card) !important;
-    border-color: var(--border) !important;
-    color: var(--text) !important;
-    border-radius: 10px !important;
-}
+/* ── Divider ── */
+hr { border-color: #1a1a1a !important; }
 
-/* ── st.chat_message styling ── */
-[data-testid="stChatMessage"] {
-    background: #111d35 !important;
-    border: 1px solid #1e3058 !important;
-    border-radius: 12px !important;
-    padding: 0.8rem 1rem !important;
-    margin: 0.5rem 0 !important;
-}
-[data-testid="stChatMessageContent"] p {
-    color: #e2e8f0 !important;
-    font-family: 'Nunito', sans-serif !important;
-    font-size: 0.93rem !important;
-    line-height: 1.8 !important;
-}
-/* Make math blocks stand out */
-.katex-display {
-    background: rgba(56,189,248,0.05) !important;
-    border-left: 3px solid #38bdf8 !important;
-    padding: 0.5rem 1rem !important;
-    border-radius: 0 8px 8px 0 !important;
-    margin: 0.5rem 0 !important;
+/* ── Selectbox ── */
+.stSelectbox > div > div {
+    background: #1a1a1a !important;
+    border-color: #2a2a2a !important;
+    color: #ececec !important;
+    border-radius: 8px !important;
+    font-size: 0.82rem !important;
 }
-
 </style>
 """, unsafe_allow_html=True)
 
-# ─── Session State ──────────────────────────────────────────────────────────────
+# ── Session state ────────────────────────────────────────────────────
 if "messages" not in st.session_state:
     st.session_state.messages = []
 if "last_submitted" not in st.session_state:
-    st.session_state.last_submitted = ""  # prevents infinite rerun loop
+    st.session_state.last_submitted = ""
 
-# ─── SymPy Engine ───────────────────────────────────────────────────────────────
+
+# ════════════════════════════════════════════════════════════════════
+# SYMPY ENGINE — exact symbolic computation, no AI needed for this
+# ════════════════════════════════════════════════════════════════════
 def run_sympy(problem: str) -> dict:
     """
-    Safely attempt symbolic computation.
-    Uses sp.* explicitly — no wildcard collisions possible here.
+    Attempt symbolic computation using SymPy.
+    Returns verified result dict. Falls back silently on any error.
+    All sympy calls use sp.* explicitly to avoid wildcard name collisions.
     """
     p = problem.lower().strip()
     x = sp.Symbol('x')
-    default = {"type": "general", "result": None, "latex": ""}
-
-    try:
-        tfms = standard_transformations + (implicit_multiplication_application,)
+    tfms = standard_transformations + (implicit_multiplication_application,)
+
+    # local_dict maps common names to correct sympy objects
+    # Critical: 'e' must map to E (Euler's number), not unknown symbol
+    ld = {
+        "x": x,
+        "e": sp.E, "E": sp.E,
+        "pi": sp.pi, "PI": sp.pi,
+        "sin": sp.sin, "cos": sp.cos, "tan": sp.tan,
+        "exp": sp.exp, "log": sp.log, "ln": sp.log,
+        "sqrt": sp.sqrt, "inf": sp.oo, "oo": sp.oo
+    }
 
-        def clean(s):
-            """Normalise expression string for sympy parsing."""
-            s = re.sub(r"\s+", "", s)
-            s = re.sub(r"\^", "**", s)
-            return s
+    def clean(s):
+        """Normalize expression: strip spaces, convert ^ to **"""
+        s = re.sub(r"\s+", "", s)
+        s = re.sub(r"\^", "**", s)
+        return s
 
-        # ── Derivative ──
+    try:
+        # ── Derivative ──────────────────────────────────────────────
         if any(k in p for k in ["derivative", "differentiate", "d/dx", "diff"]):
             raw = p
             for kw in ["derivative of", "differentiate", "diff of", "d/dx of", "d/dx"]:
@@ -273,11 +237,11 @@ def run_sympy(problem: str) -> dict:
                     raw = p.split(kw, 1)[-1].strip()
                     break
             raw = re.sub(r"\s*(dx|with\s*respect\s*to\s*x).*$", "", raw).strip()
-            expr = parse_expr(clean(raw), transformations=tfms, local_dict={"x": x, "e": sp.E, "E": sp.E, "pi": sp.pi, "ln": sp.log, "inf": sp.oo})
+            expr = parse_expr(clean(raw), transformations=tfms, local_dict=ld)
             result = sp.diff(expr, x)
             return {"type": "Derivative", "result": str(result), "latex": sp.latex(result)}
 
-        # ── Integral ──
+        # ── Integral ────────────────────────────────────────────────
         elif any(k in p for k in ["integral", "integrate", "antiderivative"]):
             raw = p
             for kw in ["integral of", "integrate", "antiderivative of"]:
@@ -285,253 +249,278 @@ def run_sympy(problem: str) -> dict:
                     raw = p.split(kw, 1)[-1].strip()
                     break
             raw = re.sub(r"\s*dx.*$", "", raw).strip()
-            expr = parse_expr(clean(raw), transformations=tfms, local_dict={"x": x, "e": sp.E, "E": sp.E, "pi": sp.pi, "ln": sp.log, "inf": sp.oo})
+            expr = parse_expr(clean(raw), transformations=tfms, local_dict=ld)
             result = sp.integrate(expr, x)
             return {"type": "Integral", "result": str(result), "latex": sp.latex(result)}
 
-        # ── Limit ──
+        # ── Limit ───────────────────────────────────────────────────
         elif "limit" in p:
             match = re.search(
-                r"limit\s+of\s+([\w\s\(\)\+\-\*/\^\.\,]+?)\s+as\s+x\s*(?:->|→|approaches)\s*([\w\.\+\-]+)",
+                r"limit\s+of\s+([\w\s\(\)\+\-\*/\^\.\,]+?)"
+                r"\s+as\s+x\s*(?:->|→|approaches)\s*([\w\.\+\-]+)",
                 p
             )
             if match:
                 raw_expr = clean(match.group(1))
-                point_str = match.group(2).strip()
-                point = sp.oo if point_str in ("inf", "infinity", "oo") else sp.sympify(point_str)
-                expr = parse_expr(raw_expr, transformations=tfms, local_dict={"x": x, "e": sp.E, "E": sp.E, "pi": sp.pi, "ln": sp.log, "inf": sp.oo})
+                pt = match.group(2).strip()
+                point = sp.oo if pt in ("inf", "infinity", "oo") else sp.sympify(pt)
+                expr = parse_expr(raw_expr, transformations=tfms, local_dict=ld)
                 result = sp.limit(expr, x, point)
                 return {"type": "Limit", "result": str(result), "latex": sp.latex(result)}
 
-        # ── Solve equation ──
+        # ── Solve equation ──────────────────────────────────────────
         elif any(k in p for k in ["solve", "roots", "find x"]):
-            raw = re.sub(r"(solve|find x|roots of|roots|the equation)", "", p).strip().strip(": ")
+            raw = re.sub(r"(solve|find x|roots of|roots|the equation)", "", p)
+            raw = raw.strip().strip(":").strip()
             if "=" in raw:
                 lhs_s, rhs_s = raw.split("=", 1)
-                lhs_e = parse_expr(clean(lhs_s), transformations=tfms, local_dict={"x": x, "e": sp.E, "E": sp.E, "pi": sp.pi, "ln": sp.log, "inf": sp.oo})
-                rhs_e = parse_expr(clean(rhs_s), transformations=tfms, local_dict={"x": x, "e": sp.E, "E": sp.E, "pi": sp.pi, "ln": sp.log, "inf": sp.oo})
+                lhs_e = parse_expr(clean(lhs_s), transformations=tfms, local_dict=ld)
+                rhs_e = parse_expr(clean(rhs_s), transformations=tfms, local_dict=ld)
                 expr = lhs_e - rhs_e
             else:
-                expr = parse_expr(clean(raw), transformations=tfms, local_dict={"x": x, "e": sp.E, "E": sp.E, "pi": sp.pi, "ln": sp.log, "inf": sp.oo})
+                expr = parse_expr(clean(raw), transformations=tfms, local_dict=ld)
+            # Guard: only solve if x is actually in the expression
             if x in expr.free_symbols:
                 sol = sp.solve(expr, x)
                 sol_latex = ", ".join([sp.latex(s) for s in sol])
-                return {"type": "Equation", "result": str(sol), "latex": f"x \\in \\{{{sol_latex}\\}}"}
-
-        # ── Matrix / eigenvalues — delegate to Claude ──
-        elif any(k in p for k in ["matrix", "determinant", "eigenvalue", "eigenvector", "det("]):
+                return {
+                    "type": "Equation",
+                    "result": str(sol),
+                    "latex": r"x \in \{" + sol_latex + r"\}"
+                }
+
+        # ── Matrix / Eigenvalues — too varied, delegate to AI ───────
+        elif any(k in p for k in ["matrix", "determinant", "eigenvalue",
+                                   "eigenvector", "det("]):
             return {"type": "Matrix", "result": "matrix_detected", "latex": ""}
 
-        # ── Modular arithmetic — delegate to Claude ──
+        # ── Modular arithmetic — delegate to AI ─────────────────────
         elif "mod" in p or "congruence" in p:
             return {"type": "NumberTheory", "result": "mod_detected", "latex": ""}
 
     except Exception:
-        pass  # fall back gracefully; Claude handles it without sympy hint
+        pass  # Silently fall back — AI handles it without sympy hint
 
-    return default
+    return {"type": "general", "result": None, "latex": ""}
 
 
-# ─── Groq API (100% free, fast, reliable) ───────────────────────────────────────
-def ask_claude(problem: str, sympy_info: dict, history: list) -> str:
-    import requests
-
+# ════════════════════════════════════════════════════════════════════
+# GROQ API — free, fast, Llama 3.3 70B
+# ════════════════════════════════════════════════════════════════════
+def ask_ai(problem: str, sympy_info: dict, history: list) -> str:
     api_key = os.environ.get("GROQ_API_KEY", "")
     if not api_key:
         return (
             "⚠️ **GROQ_API_KEY not set.**\n\n"
-            "1. Go to https://console.groq.com\n"
-            "2. Sign up free → API Keys → Create API Key\n"
-            "3. HF Space → Settings → Secrets → add GROQ_API_KEY"
+            "**Steps to fix:**\n"
+            "1. Go to https://console.groq.com → sign up free\n"
+            "2. API Keys → Create API Key → copy it\n"
+            "3. HF Space → Settings → Secrets → add `GROQ_API_KEY`"
         )
 
+    # Build sympy context if we have a verified result
     sympy_context = ""
     if (sympy_info.get("result")
             and sympy_info["result"] not in (None, "matrix_detected", "mod_detected")):
         sympy_context = (
-            f"SYMPY VERIFIED RESULT (your final answer MUST match this):\n"
-            f"- Operation: {sympy_info.get('type', 'N/A')}\n"
-            f"- Result: {sympy_info.get('result', 'N/A')}\n"
-            f"- LaTeX: {sympy_info.get('latex', 'N/A')}\n"
+            "\n\nSYMPY VERIFIED RESULT — your final answer MUST match this exactly:\n"
+            f"  Operation : {sympy_info.get('type', '')}\n"
+            f"  Result    : {sympy_info.get('result', '')}\n"
+            f"  LaTeX     : {sympy_info.get('latex', '')}\n"
         )
 
     system_prompt = (
-        "You are SAAD AI, an elite BSc Mathematics tutor. "
-        "Solve every problem with perfect step-by-step working. "
-        "Label every step: Step 1:, Step 2:, etc. "
-        "Use $...$ for inline math and $$...$$ for display equations. "
-        "State the method or theorem used at the start. "
-        "Show ALL intermediate algebra, never skip steps. "
-        "End every solution with: **Final Answer:** $$...$$ "
-        "NEVER make arithmetic errors. "
+        "You are SAAD AI, a precise BSc Mathematics tutor.\n\n"
+        "STRICT FORMATTING RULES — follow every rule exactly:\n"
+        "1. Start with the method name: e.g. **Method: Integration by Parts**\n"
+        "2. Label steps: **Step 1:**, **Step 2:**, etc.\n"
+        "3. ALL math must be in LaTeX — NEVER write math in plain text.\n"
+        "   - Inline math: $expression$\n"
+        "   - Display math (new line, centered): $$expression$$\n"
+        "4. NEVER write the same expression twice (once in LaTeX, once plain).\n"
+        "   BAD: 'x = 2x = 2'   GOOD: '$x = 2$'\n"
+        "5. Use emojis to mark sections:\n"
+        "   🔍 for identifying/given info\n"
+        "   🧮 for computation steps\n"
+        "   ✅ for the final answer\n"
+        "6. End EVERY solution with:\n"
+        "   ✅ **Final Answer:** $$your_answer$$\n"
+        "7. NEVER make arithmetic errors.\n"
+        "8. Keep explanations concise — one sentence per step.\n\n"
         "Topics: Calculus, Linear Algebra, Number Theory, ODEs, "
         "Numerical Methods, Differential Geometry, Hydro Mechanics, "
-        "Theory of Numbers, Real Analysis II, General Math.\n\n"
+        "Theory of Numbers, Real Analysis II, General Math."
         + sympy_context
     )
 
+    # Build messages — last 6 exchanges for context
     messages = [{"role": "system", "content": system_prompt}]
-    for msg in history[-8:]:
+    for msg in history[-12:]:
         messages.append({"role": msg["role"], "content": msg["content"]})
     messages.append({"role": "user", "content": problem})
 
-    headers = {
-        "Authorization": f"Bearer {api_key}",
-        "Content-Type": "application/json"
-    }
-    payload = {
-        "model": "llama-3.3-70b-versatile",
-        "messages": messages,
-        "max_tokens": 2048,
-        "temperature": 0.2
-    }
-
     try:
         resp = requests.post(
             "https://api.groq.com/openai/v1/chat/completions",
-            headers=headers,
-            json=payload,
+            headers={
+                "Authorization": f"Bearer {api_key}",
+                "Content-Type": "application/json"
+            },
+            json={
+                "model": "llama-3.3-70b-versatile",
+                "messages": messages,
+                "max_tokens": 2048,
+                "temperature": 0.15,      # low = precise, no hallucinations
+                "top_p": 0.9
+            },
             timeout=60
         )
         resp.raise_for_status()
         return resp.json()["choices"][0]["message"]["content"]
+
     except requests.exceptions.Timeout:
-        return "⏳ Request timed out. Please try again."
+        return "⏳ Request timed out. Please click **SOLVE** again."
+    except requests.exceptions.HTTPError as e:
+        code = e.response.status_code if e.response else "?"
+        if code == 429:
+            return "⏳ Rate limit hit. Please wait 10 seconds and try again."
+        if code == 401:
+            return "⚠️ Invalid GROQ_API_KEY. Please check your key in HF Secrets."
+        return f"⚠️ HTTP Error {code}: {str(e)}"
     except Exception as e:
-        return f"⚠️ Error: {str(e)}"
+        return f"⚠️ Unexpected error: {str(e)}"
 
 
-# ─── Sidebar ────────────────────────────────────────────────────────────────────
+# ════════════════════════════════════════════════════════════════════
+# SIDEBAR
+# ════════════════════════════════════════════════════════════════════
 with st.sidebar:
-    st.markdown("### 📚 SAAD AI ACADEMY")
-    st.markdown("---")
+    st.markdown("### 📐 SAAD AI ACADEMY")
+    st.caption("BSc Mathematics Engine")
+    st.divider()
 
-    st.markdown("**🎯 Topics Covered**")
+    st.markdown("**🎯 Topics**")
     topics = [
-        "Calculus", "Linear Algebra", "Number Theory",
-        "Differential Equations", "Numerical Methods",
-        "Differential Geometry", "Hydro Mechanics",
-        "Theory of Numbers", "Real Analysis II", "General Math"
+        "📈 Calculus", "🔢 Linear Algebra", "🔁 Number Theory",
+        "📉 Differential Equations", "🧮 Numerical Methods",
+        "📐 Differential Geometry", "🌊 Hydro Mechanics",
+        "🔍 Theory of Numbers", "📊 Real Analysis II", "➕ General Math"
     ]
-    pills_html = "".join([f'<span class="topic-pill">{t}</span>' for t in topics])
-    st.markdown(pills_html, unsafe_allow_html=True)
+    for t in topics:
+        st.caption(t)
 
-    st.markdown("---")
-    st.markdown("**⚡ Quick Examples**")
+    st.divider()
+    st.markdown("**⚡ Example Problems**")
 
     examples = {
-        "-- Choose --": "",
-        "🔢 Derivative": "Find the derivative of x^3 + 5x^2 - 3x + 7",
+        "-- Select --": "",
+        "📈 Derivative": "Find the derivative of x^3 + 5x^2 - 3x + 7",
         "∫ Integral": "Integrate sin(x) * e^x dx",
-        "📊 Eigenvalue": "Find eigenvalues of matrix [[3,1],[1,3]]",
-        "🔁 Congruence": "Solve 14x ≡ 30 (mod 44)",
-        "🌊 ODE": "Solve dy/dx + 2y = e^x",
         "📐 Limit": "Find limit of sin(x)/x as x -> 0",
-        "🔍 Series": "Test convergence of sum 1/n^2 from n=1 to infinity",
-        "📏 Newton-Raphson": "Apply Newton-Raphson to find root of x^3 - 2x - 5 = 0",
+        "🔢 Eigenvalues": "Find eigenvalues of matrix [[4,1],[2,3]]",
+        "🔁 Congruence": "Solve 14x ≡ 30 (mod 44) using Euclidean algorithm",
+        "📉 ODE": "Solve dy/dx + 2y = e^(-x) with y(0) = 1",
+        "🧮 Newton-Raphson": "Apply Newton-Raphson to x^3 - 2x - 5 = 0, x0=2, 3 iterations",
+        "📊 Series": "Test convergence of sum 1/n^2 from n=1 to infinity",
+        "🌊 Bernoulli": "Explain Bernoulli equation in fluid mechanics with example",
+        "🔍 Fermat": "State and prove Fermat's Little Theorem with example",
     }
 
-    selected_example = st.selectbox(
-        "Load an example:",
+    selected = st.selectbox(
+        "Load example:",
         list(examples.keys()),
-        key="example_select"
+        key="example_select",
+        label_visibility="collapsed"
     )
 
-    st.markdown("---")
+    st.divider()
     st.markdown("**🔧 Engine**")
-    st.markdown("""
-    <div style="font-size:0.8rem; color:#64748b; line-height:1.8;">
-    🤖 <b style="color:#38bdf8">Claude AI</b> — reasoning & steps<br>
-    🧮 <b style="color:#34d399">SymPy</b> — verified computation<br>
-    ✅ Zero arithmetic errors
-    </div>
-    """, unsafe_allow_html=True)
+    st.caption("🤖 Groq Llama 3.3 70B — reasoning")
+    st.caption("🧮 SymPy — verified computation")
+    st.caption("✅ Zero arithmetic errors")
 
-    st.markdown("---")
-    if st.button("🗑️ Clear Chat"):
+    st.divider()
+    if st.button("🗑️ Clear Chat", use_container_width=True):
         st.session_state.messages = []
         st.session_state.last_submitted = ""
         st.rerun()
 
 
-# ─── Hero Banner ────────────────────────────────────────────────────────────────
+# ════════════════════════════════════════════════════════════════════
+# MAIN AREA
+# ════════════════════════════════════════════════════════════════════
+
+# Header
 st.markdown("""
-<div class="hero">
-    <div class="hero-title">📐 SAAD AI ACADEMY</div>
-    <div class="hero-sub">BSc Mathematics — Computational Engine</div>
+<div class="saad-header">
+    <h1>📐 SAAD AI ACADEMY</h1>
+    <p>BSc Mathematics — Step-by-Step Solver</p>
     <div class="badge-row">
-        <span class="badge">Claude AI</span>
+        <span class="badge">Groq Free</span>
         <span class="badge">SymPy Verified</span>
         <span class="badge">Step-by-Step</span>
-        <span class="badge">Zero Errors</span>
-        <span class="badge">LaTeX Output</span>
+        <span class="badge">LaTeX Rendered</span>
     </div>
 </div>
 """, unsafe_allow_html=True)
 
-
-# ─── Chat Display (uses st.chat_message for proper LaTeX rendering) ─────────────
+# Welcome message if no chat
 if not st.session_state.messages:
     st.markdown("""
-    <div style="display:flex;flex-direction:column;align-items:center;justify-content:center;
-                height:260px;text-align:center;
-                background:#0d1526;border:1px solid #1e3058;border-radius:14px;
-                margin-bottom:1rem;">
-        <div style="font-size:3rem;margin-bottom:0.8rem;">📐</div>
-        <div style="font-family:'Rajdhani',sans-serif;font-size:1.2rem;
-                    color:#475569;letter-spacing:1px;">
-            Ask any BSc Mathematics problem
-        </div>
-        <div style="font-size:0.82rem;color:#334155;margin-top:0.5rem;">
+    <div style="text-align:center; padding:2rem 1rem; color:#444;">
+        <div style="font-size:2.5rem; margin-bottom:0.5rem;">🧮</div>
+        <div style="font-size:0.9rem; color:#555;">
+            Ask any BSc Mathematics problem below<br>
+            <span style="font-size:0.78rem; color:#333;">
             Calculus · Linear Algebra · Number Theory · ODEs · Real Analysis · and more
+            </span>
         </div>
     </div>
     """, unsafe_allow_html=True)
-else:
-    for msg in st.session_state.messages:
-        if msg["role"] == "user":
-            with st.chat_message("user", avatar="🧑‍🎓"):
-                st.markdown(msg["content"])
-        else:
-            with st.chat_message("assistant", avatar="📐"):
-                st.markdown(msg["content"])
-
-# ─── Input Row ──────────────────────────────────────────────────────────────────
-col1, col2 = st.columns([5, 1])
-
-with col1:
-    prefill = examples.get(selected_example, "") if selected_example != "-- Choose --" else ""
-    user_input = st.text_input(
-        label="problem_input",
-        value=prefill,
-        placeholder="Type a BSc math problem... e.g. 'Solve d²y/dx² + 4y = cos(2x)'",
-        label_visibility="collapsed",
-        key="user_input_field"
-    )
 
-with col2:
-    send_btn = st.button("SOLVE →", use_container_width=True)
+# Render chat history
+for msg in st.session_state.messages:
+    avatar = "🧑‍🎓" if msg["role"] == "user" else "📐"
+    with st.chat_message(msg["role"], avatar=avatar):
+        st.markdown(msg["content"])
+
+# ════════════════════════════════════════════════════════════════════
+# INPUT — use st.chat_input (cleaner than text_input + button)
+# ════════════════════════════════════════════════════════════════════
+
+# Pre-fill from example selector
+prefill = examples.get(selected, "") if selected != "-- Select --" else ""
 
+# st.chat_input is the clean ChatGPT-style input bar
+user_input = st.chat_input(
+    placeholder="Type a BSc math problem... e.g. 'Solve d²y/dx² + 4y = cos(2x)'",
+)
 
-# ─── Process Input ───────────────────────────────────────────────────────────────
-# Only fires when SOLVE is clicked, input is non-empty, AND it's a new problem
-# This prevents the infinite rerun loop caused by value="" pre-fill on every cycle
-problem = user_input.strip() if user_input else ""
+# Also allow clicking an example to submit it directly
+if prefill and prefill != st.session_state.last_submitted:
+    problem = prefill
+elif user_input and user_input.strip():
+    problem = user_input.strip()
+else:
+    problem = ""
 
-if send_btn and problem and problem != st.session_state.last_submitted:
+# ════════════════════════════════════════════════════════════════════
+# PROCESS — only when there's a new problem
+# ════════════════════════════════════════════════════════════════════
+if problem and problem != st.session_state.last_submitted:
     st.session_state.last_submitted = problem
 
-    with st.spinner("🧮 Running SymPy verification + Claude reasoning..."):
-        sympy_result = run_sympy(problem)
-        try:
-            answer = ask_claude(problem, sympy_result, st.session_state.messages)
-        except Exception as e:
-            answer = (
-                f"⚠️ **API Error:** {str(e)}\n\n"
-                "Please ensure **ANTHROPIC_API_KEY** is added in your Hugging Face Space → "
-                "Settings → Variables and Secrets."
-            )
+    # Show user message immediately
+    with st.chat_message("user", avatar="🧑‍🎓"):
+        st.markdown(problem)
+
+    # Show AI response
+    with st.chat_message("assistant", avatar="📐"):
+        with st.spinner("🧮 Computing..."):
+            sympy_result = run_sympy(problem)
+            answer = ask_ai(problem, sympy_result, st.session_state.messages)
+        st.markdown(answer)
 
+    # Save to history
     st.session_state.messages.append({"role": "user", "content": problem})
     st.session_state.messages.append({"role": "assistant", "content": answer})
-    st.rerun()