:root {
  --blue: #0056B3;
  --dark: #1A2B4A;
  --gray: #8E8E8E;
  --bg: #f4f7fb;
  --white: #fff;
}

* { box-sizing: border-box; margin: 0; padding: 0; }

body {
  font-family: Inter, system-ui, sans-serif;
  background: var(--bg);
  color: var(--dark);
  min-height: 100vh;
}

.login {
  min-height: 100vh;
  display: grid;
  place-items: center;
  padding: 1rem;
}

.login__card {
  background: var(--white);
  padding: 2rem;
  border-radius: 16px;
  box-shadow: 0 8px 30px rgba(26, 43, 74, 0.1);
  width: 100%;
  max-width: 380px;
  text-align: center;
}

.login__card img { margin: 0 auto 1rem; }

.login__card h1 { font-size: 1.25rem; margin-bottom: 0.25rem; }

.login__card p { color: var(--gray); margin-bottom: 1.5rem; font-size: 0.9rem; }

.login__card input {
  width: 100%;
  padding: 0.75rem 1rem;
  border: 1px solid #dde3ea;
  border-radius: 8px;
  margin-bottom: 0.75rem;
  font: inherit;
}

.login__card button, .btn {
  border: none;
  border-radius: 8px;
  padding: 0.75rem 1rem;
  font: inherit;
  font-weight: 600;
  cursor: pointer;
}

.login__card button, .btn--primary {
  background: var(--blue);
  color: var(--white);
}

.panel { min-height: 100vh; display: flex; flex-direction: column; }

.panel__header {
  background: var(--white);
  border-bottom: 1px solid #e8ecf0;
  padding: 1rem 1.25rem;
  display: flex;
  justify-content: space-between;
  align-items: center;
}

.panel__header > div {
  min-width: 0;
  flex: 1;
}

.panel__header span {
  display: block;
  color: var(--gray);
  font-size: 0.85rem;
  overflow: hidden;
  text-overflow: ellipsis;
  white-space: nowrap;
}

.panel__body {
  flex: 1;
  display: grid;
  grid-template-columns: 320px 1fr;
  min-height: 0;
}

.inbox {
  background: var(--white);
  border-right: 1px solid #e8ecf0;
  overflow-y: auto;
}

.inbox__item {
  padding: 1rem;
  border-bottom: 1px solid #f0f3f7;
  cursor: pointer;
}

.inbox__item:hover, .inbox__item--active { background: #f0f6ff; }

.inbox__item strong {
  display: block;
  font-size: 0.9rem;
  margin-bottom: 0.25rem;
  white-space: nowrap;
  overflow: hidden;
  text-overflow: ellipsis;
}

.inbox__item span, .inbox__item small {
  display: block;
  color: var(--gray);
  font-size: 0.8rem;
  white-space: nowrap;
  overflow: hidden;
  text-overflow: ellipsis;
}

.message {
  padding: 1.5rem;
  overflow-y: auto;
}

.message__empty { color: var(--gray); }

.message__header {
  background: var(--white);
  border-radius: 12px;
  padding: 1.25rem;
  margin-bottom: 1rem;
}

.message__body {
  background: var(--white);
  border-radius: 12px;
  padding: 1.25rem;
  white-space: pre-wrap;
  line-height: 1.6;
}

.message__actions { margin-top: 1rem; }

.message__back {
  display: none;
  align-items: center;
  gap: 0.35rem;
  background: none;
  border: none;
  color: var(--blue);
  font: inherit;
  font-weight: 600;
  font-size: 0.9rem;
  padding: 0;
  margin-bottom: 1rem;
  cursor: pointer;
}

dialog {
  border: none;
  border-radius: 16px;
  padding: 1.5rem;
  width: min(520px, 92vw);
  box-shadow: 0 20px 60px rgba(0,0,0,0.2);
}

dialog form { display: flex; flex-direction: column; gap: 0.75rem; }

dialog label { display: flex; flex-direction: column; gap: 0.35rem; font-size: 0.9rem; font-weight: 600; }

dialog input, dialog textarea {
  font: inherit;
  padding: 0.65rem 0.75rem;
  border: 1px solid #dde3ea;
  border-radius: 8px;
  font-weight: 400;
}

.dialog__actions { display: flex; justify-content: flex-end; gap: 0.5rem; margin-top: 0.5rem; }

.error { color: #c0392b; font-size: 0.85rem; }

.inbox__loading { padding: 1rem; color: var(--gray); }

dialog::backdrop {
  background: rgba(26, 43, 74, 0.45);
}

@media (min-width: 1024px) {
  .panel__body {
    grid-template-columns: minmax(280px, 340px) 1fr;
    max-width: 1400px;
    margin: 0 auto;
    width: 100%;
  }

  .message__header,
  .message__body {
    max-width: 72ch;
  }

  .message__empty {
    max-width: 48ch;
    margin: 2rem auto;
    text-align: center;
  }

  dialog {
    width: 560px;
    max-width: 92vw;
  }
}

@media (min-width: 1440px) {
  .panel__body {
    grid-template-columns: 360px 1fr;
  }

  .message {
    padding: 2rem;
  }
}

@media (max-width: 768px) {
  .panel__header {
    flex-wrap: wrap;
    gap: 0.75rem;
    padding: 0.75rem 1rem;
  }

  .panel__header .btn--primary {
    padding: 0.5rem 0.75rem;
    font-size: 0.85rem;
    flex-shrink: 0;
  }

  .panel__body {
    grid-template-columns: 1fr;
  }

  .message {
    display: none;
    padding: 1rem;
  }

  .panel__body--reading .inbox {
    display: none;
  }

  .panel__body--reading .message {
    display: block;
  }

  .message__back {
    display: inline-flex;
    min-height: 44px;
  }

  dialog {
    max-height: 90dvh;
    overflow-y: auto;
  }

  input,
  textarea,
  select {
    font-size: 16px;
  }
}