diff --git a/main.tex b/main.tex
index e90cdd1..80f036b 100644
--- a/main.tex
+++ b/main.tex
@@ -1,9 +1,9 @@
 \documentclass[a4paper,twocolumn]{article}
 
+\usepackage{booktabs}
 \usepackage{baskervald}
 \usepackage{courierten}
 \usepackage{cuted}
-\usepackage[margin=2cm]{geometry}
 \usepackage{helvet}
 \usepackage{mathtools}
 \usepackage{sectsty}
@@ -27,96 +27,125 @@
 
 \section{Instructions}
 
-\begin{tabularx}{\colwidth}{|>{\ttfamily}l|>{$}X<{$}|}
-  \hline
-  add \ S,D & D \leftarrow S + D \\ \hline
-  sub \ S,D & D \leftarrow D - S \\ \hline
-  neg \ D & D \leftarrow -D \\ \hline
-  inc \ D & D \leftarrow D + 1 \\ \hline
-  dec \ D & D \leftarrow D - 1 \\ \hline
-  imul S,D & D \leftarrow S \times D \\ \hline
-  idiv S & \mathtt{rax} \leftarrow \lfloor\mathtt{rdx}:\mathtt{rax} \div S\rfloor \\
-  & \mathtt{rdx} \leftarrow (\mathtt{rdx}:\mathtt{rax})\mod{S} \\ \hline
-  \hline
-  and S,D & D \leftarrow S \mathbin{\&} D \\ \hline
-  or \ S,D & D \leftarrow S \mathbin{|} D \\ \hline
-  xor S,D & D \leftarrow S \wedge D \\ \hline 
-  not D & D \leftarrow \mathord{\sim} D \\ \hline
-  sal n,D & D \leftarrow D \ll n \\ \hline
-  shr n,D & D \leftarrow D \gg n \hspace{1em} \textrm{(logical)} \\ \hline
-  sar n,D & D \leftarrow D \gg n \hspace{1em} \textrm{(arithmetic)} \\ \hline
-  \hline
-  lea S,D & D \leftarrow \mathrm{addressof}(S) \\ \hline
-  mov S,D & D \leftarrow S \\ \hline
-  \hline
-  cmp \ A,B & B - A \hspace{1em} \textrm{(setting cond. flags)} \\ \hline
-  test A,B & A \mathbin{\&} B \hspace{1em} \textrm{(setting cond. flags)} \\ \hline
-  \hline
-  jmp l & \textrm{jump unconditionally} \\ \hline
-  je \ l & \textrm{jump if equal} \\ \hline
-  jne l & \textrm{jump if not equal} \\ \hline
-  js \ l & \textrm{jump if negative} \\ \hline
-  jns l & \textrm{jump if non-negative} \\ \hline
-  jg \ l & \textrm{jump if greater} \\ \hline
-  jge l & \textrm{jump if greater or equal} \\ \hline
-  jl \ l & \textrm{jump if lesser} \\ \hline
-  jle l & \textrm{jump if lesser or equal} \\ \hline
-  ja \ l & \textrm{jump if above} \\ \hline
-  jae l & \textrm{jump if above or equal} \\ \hline
-  jb \ l & \textrm{jump if below} \\ \hline
-  jbe l & \textrm{jump if below or equal} \\ \hline
-  \hline
-  push S & \mathtt{rsp} \leftarrow \mathtt{rsp} - \mathrm{sizeof}(S) \\
-  & \mathrm{at}(\mathtt{rsp}) \leftarrow S \\ \hline
-  pop \ D & D \leftarrow \mathrm{at}(\mathtt{rsp}) \\
-  & \mathtt{rsp} \leftarrow \mathtt{rsp} + \mathrm{sizeof}(S) \\ \hline
-  callq l & \textrm{push instruction pointer then jump} \\ \hline
-  retq & \textrm{pop to instruction pointer} \\ \hline
+\noindent\begin{tabularx}{\colwidth}{>{\ttfamily}l>{\ttfamily}l>{$}X<{$}}
+  \toprule
+  \multicolumn{3}{>{\sffamily\bfseries}c}{Arithmetic \& Logic} \\
+  \midrule
+  add & S,D & D \leftarrow S + D \\
+  sub & S,D & D \leftarrow D - S \\
+  neg & D & D \leftarrow -D \\
+  inc & D & D \leftarrow D + 1 \\
+  dec & D & D \leftarrow D - 1 \\
+  imul & S,D & D \leftarrow S \times D \\
+  idiv & S & \mathtt{rax} \leftarrow \lfloor\mathtt{rdx}:\mathtt{rax} \div S\rfloor \\
+  & & \mathtt{rdx} \leftarrow (\mathtt{rdx}:\mathtt{rax})\mod{S} \\
+  and & S,D & D \leftarrow S \mathbin{\&} D \\
+  or & S,D & D \leftarrow S \mathbin{|} D \\
+  xor & S,D & D \leftarrow S \wedge D \\
+  not & D & D \leftarrow \mathord{\sim} D \\
+  sal & n,D & D \leftarrow D \ll n \\
+  shr & n,D & D \leftarrow D \gg n \hspace{1em} \textrm{(logical)} \\
+  sar & n,D & D \leftarrow D \gg n \hspace{1em} \textrm{(arithmetic)} \\
+  \midrule
+  \multicolumn{3}{>{\sffamily\bfseries}c}{Data transfer} \\
+  \midrule
+  lea & S,D & D \leftarrow \mathrm{addressof}(S) \\
+  mov & S,D & D \leftarrow S \\
+  \midrule
+  \multicolumn{3}{>{\sffamily\bfseries}c}{Conditionals \& Branches} \\
+  \midrule
+  cmp & A,B & B - A \hspace{1em} \textrm{(setting cond. flags)} \\
+  test & A,B & A \mathbin{\&} B \hspace{1em} \textrm{(setting cond. flags)} \\
+  jmp & l & \textrm{jump to \texttt{l} unconditionally} \\
+  je & l & \textrm{jump to \texttt{l} if equal} \\
+  jne & l & \textrm{jump to \texttt{l} if not equal} \\
+  js & l & \textrm{jump to \texttt{l} if negative} \\
+  jns & l & \textrm{jump to \texttt{l} if non-negative} \\
+  jg & l & \textrm{jump to \texttt{l} if greater} \\
+  jge & l & \textrm{jump to \texttt{l} if greater or equal} \\
+  jl & l & \textrm{jump to \texttt{l} if lesser} \\
+  jle & l & \textrm{jump to \texttt{l} if lesser or equal} \\
+  ja & l & \textrm{jump to \texttt{l} if above} \\
+  jae & l & \textrm{jump to \texttt{l} if above or equal} \\
+  jb & l & \textrm{jump to \texttt{l} if below} \\
+  jbe & l & \textrm{jump to \texttt{l} if below or equal} \\
+  \midrule
+  \multicolumn{3}{>{\sffamily\bfseries}c}{Stack operations} \\
+  \midrule
+  push & S & \mathtt{rsp} \leftarrow \mathtt{rsp} - \mathrm{sizeof}(S) \\
+  & & \mathrm{at}(\mathtt{rsp}) \leftarrow S \\
+  pop & D & D \leftarrow \mathrm{at}(\mathtt{rsp}) \\
+  & & \mathtt{rsp} \leftarrow \mathtt{rsp} + \mathrm{sizeof}(S) \\
+  callq & l & \textrm{push \texttt{rip} then jump to \texttt{l}} \\
+  retq & & \textrm{pop to \texttt{rip}} \\
+  \bottomrule
 \end{tabularx}
 
-\vspace{0.5em}
-
-\noindent\begin{tabularx}{\colwidth}{|c|l|c|c|X|}
-  \multicolumn{2}{c}{\textbf{Suffixes}} & \multicolumn{1}{c}{} & \multicolumn{2}{c}{\textbf{Condition flags}} \\ \cline{1-2} \cline{4-5}
-  b & 8 bits & & ZF & Zero \\ \cline{1-2} \cline{4-5}
-  w & 16 bits & & SF & Sign (set on negative) \\ \cline{1-2} \cline{4-5}
-  l & 32 bits & & CF & Carry (unsigned overflow) \\ \cline{1-2} \cline{4-5}
-  q & 64 bits & & OF & Overflow  (signed overflow) \\ \cline{1-2} \cline{4-5}
+\noindent\begin{tabularx}{\colwidth}{lX}
+  \toprule
+  \multicolumn{2}{>{\sffamily\bfseries}c}{Addressing Modes} \\
+  \midrule
+  Immediate & \texttt{\$C} \\
+  Register & \texttt{\%R} \\
+  Memory & \texttt{[C\textsubscript{d}](\%R\textsubscript{b}[,\%R\textsubscript{i}[,C\textsubscript{s}])} \\
+  \bottomrule
 \end{tabularx}
 
-\section{Addressing Modes}
+\[\textrm{Memory Address} = C_d + R_b + C_sR_i\]
 
-\begin{tabularx}{\colwidth}{|l|X|}
-  \hline
-  Immediate & \texttt{\$C} \\ \hline
-  Register & \texttt{\%R} \\ \hline
-  Memory & \texttt{[C\textsubscript{d}](\%R\textsubscript{b}[,\%R\textsubscript{i}[,C\textsubscript{s}])} \\ \hline
-\end{tabularx}
-
-\vspace{0.5em}
-
-\[\mathrm{address} = C_d + R_b + C_sR_i\]
+\noindent\begin{center}
+  \begin{tabular}{cl}
+    \toprule
+    \multicolumn{2}{>{\sffamily\bfseries}c}{Suffixes} \\
+    \midrule
+    b & 8 bits \\
+    w & 16 bits \\
+    l & 32 bits \\
+    q & 64 bits \\
+    \bottomrule
+  \end{tabular}
+  \hspace{1em}
+  \begin{tabular}{cl}
+    \toprule
+    \multicolumn{2}{>{\sffamily\bfseries}c}{Condition Flags} \\
+    \midrule
+    ZF & Zero \\
+    SF & Sign (set on negative) \\ 
+    CF & Carry \\
+    OF & Overflow \\
+    \bottomrule
+  \end{tabular}
+\end{center}
 
 \section{Registers}
 
-\begin{tabularx}{\colwidth}{|>{\ttfamily}l|>{\ttfamily}l|>{\ttfamily}l|>{\ttfamily}l|X|}
-  \hline
-  rax & eax & ax & al & accumulator \\ \hline
-  rbx & ebx & bx & bl & data pointer \\ \hline
-  rcx & ecx & cx & cl & counter \\ \hline
-  rdx & edx & dx & dl & I/O pointer \\ \hline
-  rsi & esi & si & sil & source pointer \\ \hline
-  rdi & edi & di & dil & destination pointer \\ \hline
-  rsp & esp & sp & spl & stack pointer \\ \hline
-  rbp & ebp & bp & bpl & base pointer \\ \hline
-  r8 & r8d & r8w & r8b & general purpose \\ \hline
-  r9 & r9d & r9w & r9b & general purpose \\ \hline
-  r10 & r10d & r10w & r10b & general purpose \\ \hline
-  r11 & r11d & r11w & r11b & general purpose \\ \hline
-  r12 & r12d & r12w & r12b & general purpose \\ \hline
-  r13 & r13d & r13w & r13b & general purpose \\ \hline
-  r14 & r14d & r14w & r14b & general purpose \\ \hline
-  r15 & r15d & r15w & r15b & general purpose \\ \hline
+\begin{tabularx}{\colwidth}{>{\ttfamily}c>{\ttfamily}c>{\ttfamily}c>{\ttfamily}cX}
+  \toprule
+  \multicolumn{5}{>{\sffamily\bfseries}c}{Standard} \\
+  \midrule
+  rax & eax & ax & al & Accumulator \\
+  rbx & ebx & bx & bl & DS data pointer \\
+  rcx & ecx & cx & cl & Counter \\
+  rdx & edx & dx & dl & I/O pointer \\
+  rsi & esi & si & sil & Source pointer \\
+  rdi & edi & di & dil & Dest. pointer \\
+  \midrule
+  \multicolumn{5}{>{\sffamily\bfseries}c}{Stack} \\
+  \midrule
+  rsp & esp & sp & spl & Stack pointer \\
+  rbp & ebp & bp & bpl & Base pointer \\
+  \midrule
+  \multicolumn{5}{>{\sffamily\bfseries}c}{64-bit Mode Only} \\
+  \midrule
+  r8 & r8d & r8w & r8b & No special use \\
+  r9 & r9d & r9w & r9b & \\
+  r10 & r10d & r10w & r10b & \\
+  r11 & r11d & r11w & r11b & \\
+  r12 & r12d & r12w & r12b & \\
+  r13 & r13d & r13w & r13b & \\
+  r14 & r14d & r14w & r14b & \\
+  r15 & r15d & r15w & r15b & \\
+  \bottomrule
 \end{tabularx}
 
 \end{document}