Panel corner borders?

[mmprod]

I'm wondering how I can get these corner borders like below....

I'm trying css - no luck so far. Other ideas?

[ustk]

@mmprod here's an example

HiseSnippet 971.3ocsV0saaaCElxIZnVaEXEnO.B8J4k.G6X6FWjUrz33rZr5Tg4rtMLLDPSQYQDJROJpj4Uj2ud6dS1av1gRVVxotcCFq9Bac9+iGdNex9JIgljHUHKmKWLmhr9B6IKD5nAQXl.M5Lj0CruZ3X+K+YzoKliSRnAHKqc9ViUq56hx97WeyoXNVPnkpPn2HYD5qXwLcoV+S9NFmeNNfdIKth2cOYDQJFH4xT.I6X2BMGStFOidA13VMazKwIQHquxtCM3v98w851oCo+y5SNhf6SIsmdTqCwgAc5SClFzsWWLx5yFFvzR0DMVSSPV6dpLXwjH4sh7B7FVBaJmZDZil.UNW84Rdf4HZzhFDw3A9EsnDDjE+xF1N4MrGaOlEvVourw8kYFbKinZCzp15vam0fW6pvqUE3sAHYUAR6lCoGYOgnXy0kVL34ysGIzTUHFtmpBkbeQ09yZ1CjfGBcyX70zyUfvpH7dZqV66Be03XGG3tJQ6dCV45iETda2m6VD4LpdfLdtT.BdOI27SLw3j+byDp1G5P5uWlpYBpWXpfnYRg2rFNu0o9rlgvDxK3bu7ogjlXgl8aozaiXZJjn5N0KpUhoVFmV46TNL1XbJPgucfTInpDOP9tLD33vDbnltE0zcM2LkmKIXtqLLDxMbpZ253BcbpXlNxnq2Jc5HF4ZAzgA0sZ1KCbgRkqG64sN1k80cgu1auFN0gLCmLS0dk4Lmm+8KpydKSdghxeWUfFG6dvAtQRE6O9Xo59+VI02KU2PUZHSYISIMCgdiw5nl9iN3v8c+Ev6Dyc4OxBzQdML5JT8RJaVj1n6WMc56btaU6TJtPpouVj2Kctyw89lBC2nMyMpRx4T0FMaHKTer.8DowSop8gYRdJckivBw5aY1e3srpj.j7ArJNJEiDL8qmSEeHpAzxoR3oeXzYXM1rZtTG32bneyLPv5L5M.wX9hZc6ynIWqkyy7c4ZCPcoyr9vh0XylChEX3hy2hP+dI2I6jEUEt0biAmTq2AhQY2UERn2mo.3njAobrdchKC89RCPedM1BCifHgoWTk9++M1r+qP7Q19LMIZyXr1FvHba7o.iKeGvCsGFFRI5R.tq84+zmFBeTNy4LXcUwf4.6KRim.reDJTcALcXlyspYlHykaYjMcfITQPlveCeVZrsQ1Zow1EFQwXhRdEIe6x7VlGjoAvjH6Mx0sGajcaix13p1migW5cEgrdpdu.ObaCry1FX2sMvdaafOcaC7nsMv9+6AZ9OIuHUKiyWaPnw9CynqrrFJvvDX1zJ5evP1XWB

[mmprod]

@mmprod This is awesome - much appreciated!