:root {
  --indigo: #5e5ce6; --blue: #0a84ff; --navy: #10243b; --ink: #1c2b3a; --muted: #64748b; --line: #e3e8ef; --bg: #f5f7fa; --panel: #fff; --tint: #eef0fd;
  --ok: #0f9d6e; --err: #c0392b; --warn: #b7791f; --radius: 10px; --side: 250px; --list: 380px;
}
[data-theme=dark] { --navy: #e6edf7; --ink: #dbe3ee; --muted: #8b9bb0; --line: #263447; --bg: #0f1722; --panel: #16202e; --tint: #1f2a45; }
* { box-sizing: border-box; }
html, body { height: 100%; margin: 0; }
body { font: 14px/1.5 -apple-system, BlinkMacSystemFont, 'Segoe UI', Roboto, Arial, sans-serif; color: var(--ink); background: var(--bg); }
a { color: var(--indigo); }
button, input, select, textarea { font: inherit; color: inherit; }
.boot { padding: 60px; text-align: center; color: var(--muted); }
.hidden { display: none !important; }

/* layout */
.shell { display: grid; grid-template-columns: var(--side) var(--list) 1fr; height: 100vh; height: 100dvh; }
.shell.single { grid-template-columns: var(--side) 1fr; }
.side { background: var(--panel); border-right: 1px solid var(--line); display: flex; flex-direction: column; overflow: auto; }
.side .brand { display: flex; align-items: center; gap: 10px; padding: 16px 16px 10px; font-weight: 800; font-size: 18px; color: var(--navy); }
.side .brand .mark { width: 28px; height: 28px; border-radius: 8px; background: linear-gradient(135deg, var(--indigo), var(--blue)); }
.side .compose { margin: 6px 14px 12px; }
.nav-item { display: flex; align-items: center; gap: 10px; padding: 7px 16px; cursor: pointer; border-radius: 0; color: var(--ink); text-decoration: none; }
.nav-item:hover { background: var(--tint); }
.nav-item.active { background: var(--tint); color: var(--indigo); font-weight: 700; }
.nav-item .badge { margin-left: auto; font-size: 11px; font-weight: 700; background: var(--indigo); color: #fff; border-radius: 999px; padding: 1px 7px; }
.nav-item .badge.err { background: var(--err); }
.nav-group { padding: 10px 16px 4px; font-size: 11px; text-transform: uppercase; letter-spacing: 1px; color: var(--muted); font-weight: 700; display: flex; justify-content: space-between; align-items: center; }
.nav-group button { border: 0; background: none; color: var(--muted); cursor: pointer; padding: 0 2px; }
.dot { width: 9px; height: 9px; border-radius: 50%; display: inline-block; flex: none; }
.side .foot { margin-top: auto; padding: 12px 16px; border-top: 1px solid var(--line); font-size: 12px; color: var(--muted); display: flex; justify-content: space-between; align-items: center; }

/* buttons & inputs */
.btn { display: inline-flex; align-items: center; gap: 6px; padding: 8px 14px; border-radius: 8px; border: 1px solid transparent; background: var(--indigo); color: #fff; font-weight: 700; cursor: pointer; font-size: 13px; }
.btn:hover { filter: brightness(.95); }
.btn.ghost { background: var(--panel); color: var(--navy); border-color: var(--line); }
.btn.ghost:hover { border-color: var(--indigo); color: var(--indigo); }
.btn.sm { padding: 5px 10px; font-size: 12px; }
.btn.danger { background: var(--err); }
.btn:disabled { opacity: .5; cursor: default; }
.icon-btn { border: 1px solid var(--line); background: var(--panel); border-radius: 8px; width: 32px; height: 32px; cursor: pointer; display: inline-grid; place-items: center; color: var(--ink); }
.icon-btn:hover { border-color: var(--indigo); color: var(--indigo); }
.icon-btn.active { background: var(--tint); color: var(--indigo); border-color: var(--indigo); }
.field { margin-bottom: 12px; }
.field label { display: block; font-size: 12px; font-weight: 700; color: var(--navy); margin-bottom: 4px; }
.field input[type=text], .field input[type=email], .field input[type=password], .field input[type=url], .field input[type=number], .field input[type=time], .field select, .field textarea {
  width: 100%; padding: 8px 10px; border: 1px solid var(--line); border-radius: 8px; background: var(--panel); font-size: 14px; }
.field textarea { min-height: 90px; resize: vertical; }
.field input:focus, .field select:focus, .field textarea:focus { outline: none; border-color: var(--indigo); box-shadow: 0 0 0 3px var(--tint); }
.row { display: grid; grid-template-columns: 1fr 1fr; gap: 10px; }
.row3 { display: grid; grid-template-columns: 2fr 1fr 1fr; gap: 10px; }
.help { font-size: 12px; color: var(--muted); }
.msg-ok { color: var(--ok); font-size: 13px; } .msg-err { color: var(--err); font-size: 13px; }

/* list */
.list { background: var(--panel); border-right: 1px solid var(--line); display: flex; flex-direction: column; min-width: 0; }
.list-head { padding: 10px 12px; border-bottom: 1px solid var(--line); display: flex; gap: 8px; align-items: center; }
.list-head input { flex: 1; padding: 7px 10px; border: 1px solid var(--line); border-radius: 8px; background: var(--bg); }
.list-body { overflow: auto; flex: 1; }
.item { padding: 10px 12px; border-bottom: 1px solid var(--line); cursor: pointer; display: grid; grid-template-columns: 10px 1fr auto; gap: 8px; align-items: start; }
.item:hover { background: var(--tint); }
.item.active { background: var(--tint); box-shadow: inset 3px 0 0 var(--indigo); }
.item .who { font-weight: 700; color: var(--navy); white-space: nowrap; overflow: hidden; text-overflow: ellipsis; }
.item.unread .who::before { content: ''; display: inline-block; width: 7px; height: 7px; border-radius: 50%; background: var(--blue); margin-right: 6px; vertical-align: middle; }
.item .subj { white-space: nowrap; overflow: hidden; text-overflow: ellipsis; }
.item.unread .subj { font-weight: 600; }
.item .snip { color: var(--muted); font-size: 12px; white-space: nowrap; overflow: hidden; text-overflow: ellipsis; }
.item .when { font-size: 11px; color: var(--muted); white-space: nowrap; }
.item .flags { font-size: 11px; color: var(--warn); }
.item .cnt { font-size: 11px; color: var(--muted); border: 1px solid var(--line); border-radius: 6px; padding: 0 5px; }
.compact .item { padding: 6px 12px; } .compact .item .snip { display: none; }
.empty { padding: 40px 20px; text-align: center; color: var(--muted); }

/* reader */
.reader { display: flex; flex-direction: column; min-width: 0; overflow: auto; }
.reader-head { padding: 14px 20px; border-bottom: 1px solid var(--line); background: var(--panel); position: sticky; top: 0; z-index: 2; display: flex; justify-content: space-between; gap: 12px; align-items: flex-start; }
.reader-head h2 { margin: 0; font-size: 18px; color: var(--navy); }
.tools { display: flex; gap: 6px; flex-wrap: wrap; }
.mailmsg { margin: 14px 20px; background: var(--panel); border: 1px solid var(--line); border-radius: var(--radius); }
.mailmsg .mhead { padding: 12px 16px; border-bottom: 1px solid var(--line); display: flex; justify-content: space-between; gap: 10px; cursor: pointer; }
.mailmsg .mhead b { color: var(--navy); }
.mailmsg .mhead .meta { font-size: 12px; color: var(--muted); }
.mailmsg .mbody { padding: 16px; overflow-x: auto; }
.mailmsg .mbody.plain { white-space: pre-wrap; font-family: inherit; }
.mailmsg.collapsed .mbody { display: none; }
.imgbar { background: var(--tint); padding: 6px 12px; font-size: 12px; display: flex; justify-content: space-between; align-items: center; }
.atts { padding: 8px 16px 12px; display: flex; gap: 8px; flex-wrap: wrap; }
.att { border: 1px solid var(--line); border-radius: 8px; padding: 6px 10px; font-size: 12px; text-decoration: none; color: var(--ink); }
.aibox { margin: 0 20px 14px; background: var(--tint); border-radius: var(--radius); padding: 12px 16px; white-space: pre-wrap; font-size: 13px; }

/* compose */
.overlay { position: fixed; inset: 0; background: rgba(16, 36, 59, .35); z-index: 20; display: grid; place-items: end center; }
.compose { width: min(760px, 100%); max-height: 92vh; background: var(--panel); border-radius: 14px 14px 0 0; box-shadow: 0 -10px 40px rgba(0,0,0,.2); display: flex; flex-direction: column; }
.compose .chead { padding: 12px 16px; border-bottom: 1px solid var(--line); display: flex; justify-content: space-between; align-items: center; font-weight: 700; color: var(--navy); }
.compose .cbody { padding: 12px 16px; overflow: auto; }
.compose .cline { display: flex; gap: 8px; align-items: center; border-bottom: 1px solid var(--line); padding: 6px 0; }
.compose .cline label { width: 60px; font-size: 12px; color: var(--muted); }
.compose .cline input, .compose .cline select { flex: 1; border: 0; background: none; padding: 4px 0; }
.compose .cline input:focus { outline: none; }
.compose textarea { width: 100%; min-height: 220px; border: 0; padding: 12px 0; resize: vertical; background: none; }
.compose textarea:focus { outline: none; }
.compose .cfoot { padding: 10px 16px; border-top: 1px solid var(--line); display: flex; gap: 8px; align-items: center; flex-wrap: wrap; }
.fnprev { border-top: 1px dashed var(--line); padding-top: 10px; margin-top: 6px; font-size: 12px; color: var(--muted); }

/* settings */
.settings { padding: 24px 28px; max-width: 900px; overflow: auto; }
.settings h1 { font-size: 24px; color: var(--navy); margin: 0 0 4px; }
.tabs { display: flex; gap: 6px; margin: 16px 0 20px; flex-wrap: wrap; }
.tab { padding: 7px 14px; border-radius: 999px; border: 1px solid var(--line); background: var(--panel); cursor: pointer; font-weight: 600; }
.tab.active { background: var(--navy); color: #fff; border-color: var(--navy); }
.card { background: var(--panel); border: 1px solid var(--line); border-radius: var(--radius); padding: 18px; margin-bottom: 14px; }
.card h3 { margin: 0 0 8px; color: var(--navy); font-size: 16px; }
.acct-row { display: flex; align-items: center; gap: 12px; padding: 10px 0; border-bottom: 1px solid var(--line); }
.acct-row:last-child { border-bottom: 0; }
.acct-row .grow { flex: 1; min-width: 0; }
.acct-row .sub { font-size: 12px; color: var(--muted); }
.swatches { display: flex; gap: 6px; flex-wrap: wrap; }
.swatch { width: 22px; height: 22px; border-radius: 50%; cursor: pointer; border: 2px solid #fff; box-shadow: 0 0 0 1px var(--line); }
.swatch.active { box-shadow: 0 0 0 2px var(--indigo); }
.toggle { display: flex; align-items: center; gap: 10px; padding: 8px 0; }
.toggle input { width: 18px; height: 18px; }
.preset-grid { display: grid; grid-template-columns: repeat(auto-fill, minmax(180px, 1fr)); gap: 8px; margin-bottom: 12px; }
.preset { border: 1px solid var(--line); border-radius: 10px; padding: 10px 12px; cursor: pointer; background: var(--panel); text-align: left; }
.preset.active { border-color: var(--indigo); box-shadow: 0 0 0 3px var(--tint); }
.preset b { display: block; color: var(--navy); }
.preset span { font-size: 12px; color: var(--muted); }

/* auth */
.auth { min-height: 100vh; display: grid; place-items: center; padding: 20px; }
.auth .card { width: min(420px, 100%); padding: 28px; }
.auth h1 { margin: 0 0 4px; color: var(--navy); font-size: 26px; }

/* toast */
.toast { position: fixed; left: 50%; bottom: 24px; transform: translateX(-50%); background: var(--navy); color: #fff; padding: 10px 16px; border-radius: 10px; font-weight: 600; z-index: 50; box-shadow: 0 10px 30px rgba(0,0,0,.25); }
[data-theme=dark] .toast { background: #fff; color: #10243b; }

.mobile-bar { display: none; gap: 8px; align-items: center; padding: 8px 12px; border-bottom: 1px solid var(--line); background: var(--panel); }
@media (max-width: 980px) {
  .shell { grid-template-columns: 1fr; }
  .side { position: fixed; inset: 0 auto 0 0; width: 260px; z-index: 15; transform: translateX(-100%); transition: .2s; }
  .side.open { transform: none; box-shadow: 0 0 40px rgba(0,0,0,.3); }
  .list, .reader, .settings { display: none; }
  .shell[data-pane=list] .list, .shell[data-pane=reader] .reader, .shell[data-pane=settings] .settings { display: flex; }
  .shell[data-pane=settings] .settings { display: block; }
  .list { border-right: 0; }
  .mobile-bar { display: flex; }
}