Double-yellow line can be crossed to turn, but not to pass/overtake; used only in the middle of a road between lanes of oncoming traffic.
Dashed-yellow line can be crossed to turn and pass/overtake.
One solid yellow + dashed yellow indicates passing on the dashed side.
Lanes separated by white travel in the same direction.
On a road with a median / neutral ground (empty space between opposing traffic lanes), the inner stripe will be solid yellow, the outer stripe will be solid white.
What line is in the middle of a normal bidirectional road with one lane in each direction outside of built-up areas? The ones found between small towns or villages
Yellow stripes, typically with sections of double-solid, half-solid-half-dashed, or dashed, as conditions allow for passing (although some remain double-yellow for their entirety). Also, in nearly all cases, a single solid white stripe will be on the outside edge (whether there is a shoulder / breakdown lane or no)
Yellow always indicates oncoming traffic (if there is a painted median in the middle, it will always be yellow; if there is a painted median between lanes going in the same direction, it will be white) and white always indicates traffic going in the same direction.