:root {
  color: #1f2630;
  background: #f4f6f7;
  font-family: Arial, sans-serif;
}

* { box-sizing: border-box; }

body { margin: 0; }

button, input { font: inherit; }

button {
  border: 0;
  border-radius: 6px;
  background: #0b6e69;
  color: #fff;
  cursor: pointer;
  font-weight: 700;
  padding: 10px 15px;
}

button:disabled { cursor: wait; opacity: 0.55; }

.layout { max-width: 960px; margin: 0 auto; padding: 24px; }

.topbar {
  align-items: center;
  display: flex;
  justify-content: space-between;
  margin-bottom: 42px;
}

.brand { color: #0b6e69; font-size: 23px; font-weight: 800; text-decoration: none; }

.topbar span, .eyebrow, .sender, .empty-state, #message-count { color: #68727f; }

.workspace { background: #fff; border: 1px solid #dfe5e8; padding: 28px; }

.inbox-header, .actions, .messages-header { align-items: center; display: flex; gap: 16px; justify-content: space-between; }

.eyebrow { margin: 0 0 8px; }

h1, h2, h3 { margin: 0; }

h1 { font-size: 27px; word-break: break-word; }

.actions { align-items: end; border-block: 1px solid #e4e9eb; flex-wrap: wrap; margin: 28px 0; padding: 22px 0; }

label { display: grid; font-size: 14px; font-weight: 700; gap: 7px; }

input { border: 1px solid #bdc8cc; border-radius: 5px; min-width: 220px; padding: 10px; }

.messages-header { margin-bottom: 16px; }

.message-list { display: grid; gap: 10px; }

.message { border: 1px solid #e0e6e8; padding: 18px; }

.message h3 { font-size: 17px; }

.message p { margin: 9px 0 0; }

.sender { direction: ltr; text-align: right; }

.empty-state { border: 1px dashed #c8d1d5; margin: 0; padding: 24px; text-align: center; }

@media (max-width: 620px) {
  .layout { padding: 15px; }
  .topbar, .inbox-header, .actions { align-items: stretch; flex-direction: column; }
  .workspace { padding: 20px; }
  input { min-width: 0; width: 100%; }
}