body {
  background: #0b1014;
  color: #fff;
  font-family: 'Roboto', 'Helvetica Neue', Helvetica, Arial, sans-serif; /* ฟอนต์ WhatsApp */
  margin: 0;
  padding: 0;
  display: flex;
  flex-direction: column;
  min-height: 100vh;
}

header {
  background: #161f27;
  padding: 15px;
  text-align: center;
}

nav {
  margin-top: 10px;
  display: flex;
  flex-wrap: wrap;
  justify-content: center;
  gap: 10px;
}

button {
  background: #5cbd6c; /* สีเขียว WhatsApp */
  border: none;
  padding: 8px 14px;
  border-radius: 6px;
  color: white;
  cursor: pointer;
  font-family: inherit; /* ป้องกันปุ่มใช้ฟอนต์อื่น */
}
button:hover {
  background: #25b359;
}

main {
  flex: 1;
  padding: 20px;
  display: flex;
  justify-content: center;
}

#upload-section {
  max-width: 1200px;
  width: 100%;
}

/* ✅ ทำให้กราฟเป็น 16:9 เสมอ */
#graph-container {
  position: relative;
  width: 100%;
  padding-top: 56.25%; /* 16:9 = 9/16 = 0.5625 */
  background: #202020;
  border-radius: 10px;
  margin-top: 15px;
}

#graph {
  position: absolute;
  top: 0;
  left: 0;
  width: 100%;
  height: 100%;
}

.controls, .bookmark {
  margin: 10px 0;
  display: flex;
  gap: 10px;
  flex-wrap: wrap;
}

.status {
  font-size: 18px;
  margin-top: 10px;
}

footer {
  background: #1f1f1f;
  text-align: center;
  padding: 15px;
}

/* ✅ Media Query สำหรับมือถือ */
@media (max-width: 768px) {
  nav {
    flex-direction: column;
    align-items: center;
  }

  button {
    width: 100%;
    max-width: 300px;
    font-size: 16px;
  }

  .controls, .bookmark {
    flex-direction: column;
    align-items: flex-start;
  }

  .status {
    font-size: 16px;
  }
}