Update .intro-header background color
Update .intro-header background color

Changed the position of .intro-header {background-color: #808080;} after the {background: no-repeat center center;}, so that intro header background color will appear if the header-img not loaded.
physics-society/physics-society.github.io,physics-society/physics-society.github.io,allenshi820/allenshi820.github.io,physics-society/physics-society.github.io,shobhitpuri/shobhitpuri.github.io,seriouspentest/seriouspentest.github.io,ZASMan/zasman.github.io,seriouspentest/seriouspentest.github.io,allenshi820/allenshi820.github.io,physics-society/physics-society.github.io,shaohua0720/shaohua0720.github.io,ZASMan/zasman.github.io,shobhitpuri/shobhitpuri.github.io,ZASMan/zasman.github.io,shaohua0720/shaohua0720.github.io,seriouspentest/seriouspentest.github.io,shobhitpuri/shobhitpuri.github.io,shaohua0720/shaohua0720.github.io,allenshi820/allenshi820.github.io