:root {
  --phan-bg: #0b1220;
  --phan-bg-2: #111827;
  --phan-panel: #ffffff;
  --phan-panel-soft: #f8fafc;
  --phan-border: #e2e8f0;
  --phan-text: #111827;
  --phan-text-muted: #64748b;
  --phan-accent: #1e3a8a;
  --phan-accent-2: #2563eb;
  --phan-accent-3: #6d28d9;
  --phan-success: #16a34a;
  --phan-danger: #dc2626;
  --phan-warning: #f59e0b;
  --phan-radius: 12px;
  --phan-radius-sm: 8px;
  --phan-shadow: 0 6px 24px rgba(15, 23, 42, 0.08);
  --phan-gradient: linear-gradient(135deg, #0b1220 0%, #1e3a8a 55%, #2563eb 100%);
  --phan-gradient-accent: linear-gradient(135deg, #2563eb 0%, #6d28d9 100%);
}

* { box-sizing: border-box; }
html, body { margin: 0; padding: 0; height: 100%; font-family: -apple-system, BlinkMacSystemFont, 'Segoe UI', Arial, sans-serif; color: var(--phan-text); background: #eef1f6; }
body { overflow: hidden; }
a { color: var(--phan-accent-2); }
button { cursor: pointer; font-family: inherit; }
.hidden { display: none !important; }

/* LOGIN */
.login-screen {
  position: fixed; inset: 0;
  background: var(--phan-gradient);
  display: flex; align-items: center; justify-content: center;
  padding: 20px;
}
.login-card {
  width: 100%; max-width: 420px;
  background: #fff; border-radius: 16px;
  padding: 36px 32px; box-shadow: 0 20px 60px rgba(0,0,0,0.25);
}
.login-logo { text-align: center; margin-bottom: 24px; }
.logo-box {
  width: 58px; height: 58px;
  margin: 0 auto 12px;
  border-radius: 14px;
  background: var(--phan-gradient-accent);
  color: #fff;
  display: flex; align-items: center; justify-content: center;
  font-size: 24px;
  box-shadow: 0 6px 18px rgba(37, 99, 235, 0.4);
}
.logo-box.sm { width: 36px; height: 36px; font-size: 16px; border-radius: 10px; box-shadow: none; }
.login-logo h1 { margin: 6px 0 4px; font-size: 24px; font-weight: 700; letter-spacing: -0.3px; color: var(--phan-text); }
.login-logo h1 span { color: var(--phan-accent-2); }
.login-logo p { margin: 0; color: var(--phan-text-muted); font-size: 14px; }
.login-form label { display: block; font-size: 13px; color: var(--phan-text-muted); margin-bottom: 14px; font-weight: 500; }
.login-form input {
  display: block; width: 100%;
  margin-top: 6px; padding: 12px 14px;
  border: 1px solid var(--phan-border); border-radius: var(--phan-radius-sm);
  font-size: 15px; color: var(--phan-text);
  background: var(--phan-panel-soft);
  transition: border-color .15s, box-shadow .15s;
}
.login-form input:focus { outline: none; border-color: var(--phan-accent-2); box-shadow: 0 0 0 3px rgba(37,99,235,0.15); background: #fff; }
.login-form button {
  width: 100%; margin-top: 8px; padding: 13px;
  background: var(--phan-gradient-accent); color: #fff;
  border: 0; border-radius: var(--phan-radius-sm);
  font-size: 15px; font-weight: 600; letter-spacing: 0.2px;
  transition: transform .12s, box-shadow .12s;
  position: relative;
}
.login-form button:hover { transform: translateY(-1px); box-shadow: 0 8px 20px rgba(37,99,235,0.35); }
.login-form button:active { transform: translateY(0); }
.login-form button .btn-spinner { display: none; }
.login-form button.loading .btn-label { visibility: hidden; }
.login-form button.loading .btn-spinner { display: inline; position: absolute; left: 50%; top: 50%; transform: translate(-50%,-50%); }
.login-error {
  margin-top: 14px; padding: 10px 12px;
  background: #fef2f2; color: #991b1b;
  border: 1px solid #fecaca; border-radius: var(--phan-radius-sm);
  font-size: 13.5px;
}
.login-footer { margin-top: 20px; text-align: center; font-size: 12px; color: var(--phan-text-muted); }
.login-footer i { color: var(--phan-success); }

/* APP */
.app { display: flex; flex-direction: column; height: 100vh; }
.topbar {
  display: flex; align-items: center;
  padding: 12px 20px;
  background: var(--phan-gradient);
  color: #fff; gap: 20px;
  box-shadow: 0 2px 12px rgba(0,0,0,0.1);
  z-index: 10;
}
.topbar-left { display: flex; align-items: center; gap: 12px; }
.topbar-title { font-size: 17px; font-weight: 700; letter-spacing: -0.2px; }
.topbar-title span { color: #93c5fd; }
.topbar-search { flex: 1; max-width: 520px; position: relative; }
.topbar-search i { position: absolute; left: 14px; top: 50%; transform: translateY(-50%); color: rgba(255,255,255,0.6); }
.topbar-search input {
  width: 100%; padding: 10px 14px 10px 38px;
  background: rgba(255,255,255,0.1);
  border: 1px solid rgba(255,255,255,0.15); border-radius: 8px;
  color: #fff; font-size: 14px;
}
.topbar-search input::placeholder { color: rgba(255,255,255,0.6); }
.topbar-search input:focus { outline: none; background: rgba(255,255,255,0.18); border-color: rgba(255,255,255,0.3); }
.topbar-right { display: flex; align-items: center; gap: 10px; }
.user-email { font-size: 13px; opacity: 0.85; }
.icon-btn {
  background: rgba(255,255,255,0.08);
  border: 1px solid rgba(255,255,255,0.1); color: #fff;
  width: 36px; height: 36px; border-radius: 8px;
  display: flex; align-items: center; justify-content: center;
  font-size: 14px; transition: background .12s;
}
.icon-btn:hover { background: rgba(255,255,255,0.18); }

.layout {
  flex: 1; display: grid;
  grid-template-columns: 240px 360px 1fr;
  min-height: 0;
}
.sidebar {
  background: #fff; border-right: 1px solid var(--phan-border);
  padding: 16px 12px; display: flex; flex-direction: column;
  min-height: 0;
}
.compose-btn {
  margin-bottom: 16px; padding: 11px 14px;
  background: var(--phan-gradient-accent); color: #fff;
  border: 0; border-radius: 10px;
  font-size: 14px; font-weight: 600;
  display: flex; align-items: center; justify-content: center; gap: 8px;
  box-shadow: 0 4px 12px rgba(37,99,235,0.3);
  transition: transform .12s, box-shadow .12s;
}
.compose-btn:hover { transform: translateY(-1px); box-shadow: 0 8px 18px rgba(37,99,235,0.4); }
.folder-list { flex: 1; overflow-y: auto; }
.folder-loading { padding: 12px; color: var(--phan-text-muted); font-size: 13px; text-align: center; }
.folder-item {
  display: flex; align-items: center; gap: 10px;
  padding: 9px 12px; border-radius: 8px;
  font-size: 14px; color: var(--phan-text);
  cursor: pointer; user-select: none;
  margin-bottom: 2px;
  transition: background .12s;
}
.folder-item i { color: var(--phan-text-muted); width: 16px; text-align: center; }
.folder-item:hover { background: var(--phan-panel-soft); }
.folder-item.active { background: #eef2ff; color: var(--phan-accent); font-weight: 600; }
.folder-item.active i { color: var(--phan-accent); }
.folder-item .folder-badge {
  margin-left: auto; background: var(--phan-accent-2); color: #fff;
  font-size: 11px; font-weight: 700;
  padding: 1px 7px; border-radius: 10px;
}
.sidebar-footer {
  margin-top: 12px; padding-top: 12px;
  border-top: 1px solid var(--phan-border);
  font-size: 11.5px; color: var(--phan-text-muted);
  line-height: 1.8;
}
.sidebar-footer i { color: var(--phan-success); margin-right: 4px; }

.messages-pane {
  display: flex; flex-direction: column;
  background: #fff; border-right: 1px solid var(--phan-border);
  min-height: 0;
}
.messages-header {
  padding: 16px 20px; border-bottom: 1px solid var(--phan-border);
  display: flex; align-items: center; justify-content: space-between;
  font-size: 17px; font-weight: 700; letter-spacing: -0.2px;
}
.folder-count { font-size: 12px; font-weight: 500; color: var(--phan-text-muted); }
.messages-list { flex: 1; overflow-y: auto; }
.empty-state { padding: 40px 20px; text-align: center; color: var(--phan-text-muted); font-size: 13.5px; }
.message-item {
  padding: 12px 18px; border-bottom: 1px solid #f1f5f9;
  cursor: pointer; transition: background .1s;
  display: flex; flex-direction: column; gap: 3px;
}
.message-item:hover { background: var(--phan-panel-soft); }
.message-item.active { background: #eef2ff; border-left: 3px solid var(--phan-accent-2); padding-left: 15px; }
.message-item.unread { background: #fff; }
.message-item.unread .msg-from,
.message-item.unread .msg-subject { font-weight: 700; color: var(--phan-text); }
.message-item .msg-row { display: flex; align-items: baseline; justify-content: space-between; gap: 8px; }
.msg-from { font-size: 14px; color: var(--phan-text); font-weight: 500; overflow: hidden; text-overflow: ellipsis; white-space: nowrap; }
.msg-date { font-size: 11.5px; color: var(--phan-text-muted); flex-shrink: 0; }
.msg-subject { font-size: 13.5px; color: var(--phan-text); overflow: hidden; text-overflow: ellipsis; white-space: nowrap; }
.msg-preview { font-size: 12.5px; color: var(--phan-text-muted); overflow: hidden; text-overflow: ellipsis; white-space: nowrap; }
.msg-unread-dot {
  width: 8px; height: 8px; border-radius: 50%;
  background: var(--phan-accent-2);
  display: inline-block; margin-right: 8px; flex-shrink: 0;
}

.reader-pane { background: #fff; min-height: 0; overflow-y: auto; display: flex; flex-direction: column; }
.reader-empty {
  flex: 1; display: flex; flex-direction: column; align-items: center; justify-content: center;
  color: var(--phan-text-muted); gap: 14px;
}
.reader-empty i { font-size: 48px; opacity: 0.4; }
.reader-content { padding: 24px 28px; }
.reader-subject { font-size: 22px; font-weight: 700; letter-spacing: -0.3px; margin-bottom: 16px; color: var(--phan-text); }
.reader-meta {
  display: flex; flex-direction: column; gap: 4px;
  padding: 14px 16px; background: var(--phan-panel-soft);
  border-radius: 10px; font-size: 13.5px;
  margin-bottom: 20px;
}
.reader-meta .meta-row { display: flex; gap: 8px; }
.reader-meta .meta-label { font-weight: 600; color: var(--phan-text-muted); min-width: 58px; }
.reader-meta .meta-value { color: var(--phan-text); }
.reader-actions {
  display: flex; gap: 8px; margin-bottom: 20px;
  padding-bottom: 16px; border-bottom: 1px solid var(--phan-border);
}
.reader-actions button {
  padding: 8px 14px; border: 1px solid var(--phan-border);
  background: #fff; border-radius: 8px;
  font-size: 13px; font-weight: 500;
  display: flex; align-items: center; gap: 6px;
  color: var(--phan-text); transition: background .12s, border-color .12s;
}
.reader-actions button:hover { background: var(--phan-panel-soft); border-color: #cbd5e1; }
.reader-actions button.danger { color: var(--phan-danger); }
.reader-actions button.danger:hover { background: #fef2f2; border-color: #fecaca; }
.reader-body { font-size: 14.5px; line-height: 1.65; color: var(--phan-text); word-break: break-word; }
.reader-body img { max-width: 100%; height: auto; }
.reader-attachments { margin-top: 20px; padding-top: 16px; border-top: 1px solid var(--phan-border); }
.reader-attachments h4 { margin: 0 0 10px; font-size: 13px; color: var(--phan-text-muted); font-weight: 600; text-transform: uppercase; letter-spacing: 1px; }
.attachment-item {
  display: inline-flex; align-items: center; gap: 8px;
  padding: 8px 12px; margin: 0 6px 6px 0;
  background: var(--phan-panel-soft); border: 1px solid var(--phan-border); border-radius: 8px;
  font-size: 13px; color: var(--phan-text); text-decoration: none;
  transition: background .12s;
}
.attachment-item:hover { background: #eef2ff; border-color: var(--phan-accent-2); }
.attachment-item i { color: var(--phan-accent-2); }

/* COMPOSE MODAL */
.compose-modal { position: fixed; inset: 0; background: rgba(15,23,42,0.5); display: flex; align-items: center; justify-content: center; padding: 20px; z-index: 100; }
.compose-card { width: 100%; max-width: 720px; max-height: 90vh; background: #fff; border-radius: 14px; display: flex; flex-direction: column; box-shadow: 0 20px 60px rgba(0,0,0,0.3); overflow: hidden; }
.compose-header { padding: 16px 22px; background: var(--phan-gradient); color: #fff; display: flex; align-items: center; justify-content: space-between; font-size: 15px; font-weight: 600; }
.compose-header .icon-btn { background: rgba(255,255,255,0.15); }
.compose-body { padding: 20px 22px; overflow-y: auto; flex: 1; }
.compose-body label { display: block; font-size: 12px; color: var(--phan-text-muted); margin-bottom: 12px; font-weight: 500; text-transform: uppercase; letter-spacing: 1px; }
.compose-body input, .compose-body textarea {
  display: block; width: 100%; margin-top: 5px;
  padding: 10px 12px; border: 1px solid var(--phan-border); border-radius: 8px;
  font-size: 14px; font-family: inherit; color: var(--phan-text);
}
.compose-body input:focus, .compose-body textarea:focus { outline: none; border-color: var(--phan-accent-2); box-shadow: 0 0 0 3px rgba(37,99,235,0.12); }
.compose-body textarea { resize: vertical; min-height: 220px; line-height: 1.55; }
.compose-footer { padding: 14px 22px; border-top: 1px solid var(--phan-border); background: var(--phan-panel-soft); display: flex; align-items: center; justify-content: space-between; gap: 12px; }
.compose-status { font-size: 13px; color: var(--phan-text-muted); }
.compose-status.success { color: var(--phan-success); }
.compose-status.error { color: var(--phan-danger); }
.compose-actions { display: flex; gap: 8px; }
.btn-primary { padding: 10px 18px; background: var(--phan-gradient-accent); color: #fff; border: 0; border-radius: 8px; font-size: 14px; font-weight: 600; display: flex; align-items: center; gap: 6px; }
.btn-primary:hover { box-shadow: 0 4px 14px rgba(37,99,235,0.35); }
.btn-primary:disabled { opacity: 0.5; cursor: not-allowed; }
.btn-secondary { padding: 10px 18px; background: #fff; color: var(--phan-text); border: 1px solid var(--phan-border); border-radius: 8px; font-size: 14px; font-weight: 500; }
.btn-secondary:hover { background: var(--phan-panel-soft); }

/* TOAST */
.toast {
  position: fixed; bottom: 24px; right: 24px;
  padding: 12px 18px; background: var(--phan-text);
  color: #fff; border-radius: 10px;
  font-size: 13.5px; box-shadow: 0 8px 24px rgba(0,0,0,0.25);
  z-index: 200;
  max-width: 340px;
}
.toast.success { background: var(--phan-success); }
.toast.error { background: var(--phan-danger); }

/* RESPONSIVE */
@media (max-width: 1100px) {
  .layout { grid-template-columns: 220px 320px 1fr; }
}
@media (max-width: 900px) {
  .layout { grid-template-columns: 1fr; }
  .sidebar, .messages-pane { display: none; }
  .app.mobile-folders .sidebar { display: flex; }
  .app.mobile-folders .messages-pane, .app.mobile-folders .reader-pane { display: none; }
  .app.mobile-list .messages-pane { display: flex; }
  .app.mobile-list .reader-pane, .app.mobile-list .sidebar { display: none; }
  .topbar-search { display: none; }
}