:root {
  color-scheme: light;
  --bg: #eef2f7;
  --surface: #ffffff;
  --surface-alt: #f7f9fc;
  --surface-strong: #e8eef8;
  --border: #d7e0eb;
  --border-strong: #bfd0e4;
  --text: #18283c;
  --muted: #637389;
  --accent: #2c6bed;
  --accent-strong: #1f54be;
  --accent-soft: #e6efff;
  --danger-bg: #fff3f2;
  --danger-border: #efc4c0;
  --danger-text: #9a3228;
  --shadow: 0 18px 36px rgba(20, 35, 58, 0.08);
}

* {
  box-sizing: border-box;
}

html {
  background: var(--bg);
}

body {
  margin: 0;
  font-family: Inter, "Segoe UI", sans-serif;
  color: var(--text);
  background:
    radial-gradient(circle at top left, rgba(44, 107, 237, 0.08), transparent 26%),
    linear-gradient(180deg, #f5f8fc 0%, var(--bg) 28%, #edf2f8 100%);
}

a {
  color: var(--accent);
  text-decoration: none;
}

a:hover {
  text-decoration: underline;
}

button,
input,
select {
  font: inherit;
}

button,
input,
select {
  min-height: 44px;
}

button {
  border: 1px solid transparent;
  border-radius: 8px;
  background: var(--accent);
  color: #fff;
  padding: 0.75rem 1rem;
  cursor: pointer;
  font-weight: 600;
}

button:hover {
  background: var(--accent-strong);
}

button:disabled {
  cursor: not-allowed;
  opacity: 0.55;
}

input,
select {
  width: 100%;
  border-radius: 8px;
  border: 1px solid var(--border);
  background: #fff;
  color: var(--text);
  padding: 0.7rem 0.85rem;
}

input:focus,
select:focus,
button:focus-visible,
.mail-row:focus-visible,
.thread-toggle:focus-visible,
.body-toggle-btn:focus-visible,
.split-resizer:focus-visible {
  outline: 2px solid var(--accent);
  outline-offset: 2px;
}

label {
  display: grid;
  gap: 0.45rem;
}

label span,
.section-kicker,
.panel-stat,
.muted,
.mail-preview,
.mail-time,
.overview-list dt,
.reader-meta dt,
.small-note,
.thread-time,
.thread-subject,
.panel-help {
  color: var(--muted);
}

.app-shell {
  max-width: 1520px;
  margin: 0 auto;
  padding: 1.5rem;
  display: grid;
  gap: 1.25rem;
}

.app-topbar,
.action-strip,
.overview-panel,
.list-panel,
.reader-card,
.shortcut-dialog {
  background: rgba(255, 255, 255, 0.92);
  border: 1px solid var(--border);
  border-radius: 8px;
  box-shadow: var(--shadow);
}

.app-topbar {
  padding: 1.5rem;
  display: flex;
  justify-content: space-between;
  align-items: flex-start;
  gap: 1.25rem;
}

.app-topbar h1 {
  margin: 0.2rem 0 0.5rem;
  font-size: 2rem;
  line-height: 1.1;
}

.topbar-copy {
  margin: 0;
  max-width: 58ch;
}

.section-kicker {
  margin: 0;
  font-size: 0.78rem;
  text-transform: uppercase;
  letter-spacing: 0.04em;
  font-weight: 700;
}

.topbar-badges {
  display: flex;
  flex-wrap: wrap;
  justify-content: flex-end;
  gap: 0.6rem;
}

.badge-pill,
.panel-stat {
  display: inline-flex;
  align-items: center;
  justify-content: center;
  min-height: 32px;
  padding: 0 0.75rem;
  border-radius: 999px;
  border: 1px solid var(--border-strong);
  background: var(--surface-alt);
  font-size: 0.88rem;
  white-space: nowrap;
}

.alert-banner {
  padding: 0.9rem 1rem;
  border-radius: 8px;
  border: 1px solid var(--danger-border);
  background: var(--danger-bg);
  color: var(--danger-text);
}

.action-strip {
  padding: 1rem;
  display: grid;
  grid-template-columns: minmax(0, 1.45fr) minmax(300px, 0.9fr) minmax(320px, 1fr);
  gap: 1rem;
  align-items: stretch;
}

.address-panel,
.quick-form {
  display: grid;
  gap: 0.85rem;
  align-content: start;
}

.address-heading,
.panel-head,
.section-head,
.mail-copy-top,
.shortcut-dialog-head {
  display: flex;
  align-items: center;
  justify-content: space-between;
  gap: 0.75rem;
}

.address-actions,
.list-toolbar-actions {
  display: flex;
  gap: 0.6rem;
}

.ghost-button,
.body-toggle-btn {
  background: #fff;
  color: var(--text);
  border: 1px solid var(--border);
}

.ghost-button:hover,
.body-toggle-btn:hover {
  background: var(--surface-alt);
}

.ghost-button-small {
  min-width: 44px;
  min-height: 40px;
  padding: 0.55rem 0.8rem;
}

.address-box {
  min-height: 64px;
  padding: 0.95rem 1rem;
  border-radius: 8px;
  border: 1px solid var(--border-strong);
  background: linear-gradient(180deg, #fdfefe, var(--surface-alt));
  font-family: ui-monospace, SFMono-Regular, Consolas, monospace;
  font-size: 1rem;
  display: flex;
  align-items: center;
  word-break: break-all;
}

.address-box-empty {
  color: var(--muted);
}

.field-group {
  display: grid;
  gap: 0.8rem;
}

.compact-group {
  grid-template-columns: minmax(0, 1fr) 140px;
}

.workspace-grid {
  display: grid;
  grid-template-columns: 280px minmax(0, 1fr);
  gap: 1rem;
  align-items: start;
}

.split-workspace {
  --split-left: 420px;
  display: grid;
  grid-template-columns: minmax(320px, var(--split-left)) 12px minmax(0, 1fr);
  gap: 0;
  align-items: start;
}

.mail-column,
.reader-column {
  min-width: 0;
}

.split-resizer {
  min-height: calc(100vh - 280px);
  display: flex;
  align-items: center;
  justify-content: center;
  cursor: col-resize;
  user-select: none;
  touch-action: none;
}

.split-resizer::before {
  content: '';
  width: 4px;
  height: 72px;
  border-radius: 999px;
  background: linear-gradient(180deg, #bfd0e4, #8ea9cc);
  box-shadow: 0 0 0 3px rgba(255, 255, 255, 0.75);
}

.split-workspace-resizing,
.split-workspace-resizing * {
  cursor: col-resize;
  user-select: none;
}

.overview-panel,
.list-panel,
.reader-card,
.shortcut-dialog {
  padding: 1rem;
}

.overview-panel,
.list-panel,
.reader-card {
  min-height: calc(100vh - 280px);
}

.overview-panel,
.list-panel,
.reader-card,
.mail-list,
.reader-section,
.reader-head-copy,
.body-panels,
.shortcut-list {
  display: grid;
  gap: 0.95rem;
}

.overview-list,
.reader-meta,
.shortcut-list {
  margin: 0;
  display: grid;
  gap: 0.9rem;
}

.overview-list div,
.reader-meta div,
.shortcut-list div {
  display: grid;
  gap: 0.24rem;
}

.overview-list dt,
.overview-list dd,
.reader-meta dt,
.reader-meta dd,
.shortcut-list dt,
.shortcut-list dd {
  margin: 0;
}

.toggle-row {
  display: inline-flex;
  align-items: center;
  gap: 0.55rem;
}

.toggle-row input {
  width: 18px;
  min-height: 18px;
  margin: 0;
}

.interval-select {
  max-width: 110px;
}

.small-note,
.panel-help {
  margin: 0;
  line-height: 1.5;
}

.panel-head-split {
  align-items: start;
}

.list-toolbar {
  display: flex;
  align-items: end;
  gap: 0.8rem;
}

.search-field {
  flex: 1;
}

.mail-list {
  align-content: start;
}

.filter-empty {
  min-height: 180px;
}

.thread-group {
  display: grid;
  gap: 0.7rem;
  padding: 0.85rem;
  border: 1px solid var(--border);
  border-radius: 8px;
  background: linear-gradient(180deg, #fbfdff, #f7fafe);
  transition: border-color 160ms ease, background 160ms ease, box-shadow 160ms ease;
}

.thread-group-selected {
  border-color: #a5bfe8;
  background: linear-gradient(180deg, #fbfdff, #f1f6ff);
  box-shadow: inset 3px 0 0 rgba(44, 107, 237, 0.75);
}

.thread-head,
.thread-meta,
.thread-head-copy {
  display: flex;
  align-items: center;
  justify-content: space-between;
  gap: 0.75rem;
}

.thread-head-copy {
  min-width: 0;
}

.thread-toggle {
  flex: 1;
  min-width: 0;
  min-height: 0;
  display: grid;
  grid-template-columns: 18px minmax(0, 1fr);
  gap: 0.8rem;
  align-items: start;
  padding: 0;
  border: 0;
  border-radius: 0;
  background: transparent;
  color: inherit;
  text-align: left;
}

.thread-toggle:hover {
  background: transparent;
}

.thread-toggle-icon {
  width: 18px;
  min-height: 18px;
  position: relative;
  margin-top: 0.15rem;
}

.thread-toggle-icon::before {
  content: '';
  position: absolute;
  top: 5px;
  left: 4px;
  width: 8px;
  height: 8px;
  border-right: 2px solid #7590b5;
  border-bottom: 2px solid #7590b5;
  transform: rotate(45deg);
  transform-origin: center;
  transition: transform 160ms ease, top 160ms ease;
}

.thread-group-collapsed .thread-toggle-icon::before {
  top: 3px;
  transform: rotate(-45deg);
}

.thread-title-row,
.thread-preview-row {
  min-width: 0;
  display: flex;
  align-items: center;
  gap: 0.6rem;
}

.thread-sender,
.thread-subject,
.thread-preview {
  min-width: 0;
  overflow: hidden;
  text-overflow: ellipsis;
  white-space: nowrap;
}

.thread-sender {
  font-size: 0.95rem;
}

.thread-subject {
  font-size: 0.88rem;
}

.thread-preview {
  font-size: 0.88rem;
  color: var(--muted);
}

.thread-count {
  display: inline-flex;
  align-items: center;
  min-height: 24px;
  padding: 0 0.5rem;
  border-radius: 999px;
  border: 1px solid var(--border);
  background: #fff;
  font-size: 0.78rem;
  color: var(--muted);
  white-space: nowrap;
}

.thread-chip {
  display: inline-flex;
  align-items: center;
  min-height: 24px;
  padding: 0 0.5rem;
  border-radius: 999px;
  background: var(--accent-soft);
  border: 1px solid #bfd2fb;
  color: var(--accent-strong);
  font-size: 0.76rem;
  font-weight: 700;
  white-space: nowrap;
}

.thread-items {
  display: grid;
  gap: 0.55rem;
}

.thread-group-collapsed .thread-items {
  display: none;
}

.mail-row {
  display: grid;
  grid-template-columns: 10px 44px minmax(0, 1fr);
  gap: 0.85rem;
  align-items: start;
  padding: 0.9rem;
  border-radius: 8px;
  border: 1px solid var(--border);
  background: #fff;
  color: inherit;
  position: relative;
  transition: border-color 160ms ease, background 160ms ease, box-shadow 160ms ease, transform 160ms ease;
}

.mail-row:hover,
.mail-row-active {
  background: var(--surface-alt);
  border-color: var(--border-strong);
  text-decoration: none;
}

.mail-row:hover {
  transform: translateY(-1px);
  box-shadow: 0 10px 20px rgba(21, 41, 71, 0.07);
}

.mail-row-active {
  background: linear-gradient(180deg, #f8fbff, #eef5ff);
  border-color: #95b6ef;
  box-shadow: inset 3px 0 0 var(--accent), 0 12px 24px rgba(39, 89, 174, 0.1);
}

.mail-row-cursor {
  border-color: #91afe0;
  box-shadow: 0 0 0 2px rgba(44, 107, 237, 0.14);
}

.mail-row-filtered-out {
  display: none;
}

.mail-state {
  width: 10px;
  min-height: 44px;
  display: flex;
  align-items: center;
  justify-content: center;
}

.mail-state::before {
  content: '';
  width: 0.7rem;
  height: 0.7rem;
  border-radius: 999px;
  background: transparent;
  border: 1px solid transparent;
}

.mail-row-unread .mail-state::before {
  background: var(--accent);
  border-color: rgba(44, 107, 237, 0.18);
  box-shadow: 0 0 0 5px rgba(44, 107, 237, 0.12);
}

.mail-row-unread .mail-from,
.mail-row-unread .mail-subject {
  font-weight: 700;
}

.mail-avatar {
  width: 44px;
  height: 44px;
  border-radius: 50%;
  background: var(--accent-soft);
  color: var(--accent-strong);
  font-weight: 700;
  display: inline-flex;
  align-items: center;
  justify-content: center;
}

.mail-copy {
  min-width: 0;
  display: grid;
  gap: 0.32rem;
}

.mail-copy-top,
.mail-title-row {
  min-width: 0;
}

.mail-title-row {
  display: flex;
  align-items: center;
  gap: 0.55rem;
}

.mail-from,
.mail-subject {
  display: block;
  min-width: 0;
  overflow: hidden;
  text-overflow: ellipsis;
  white-space: nowrap;
}

.mail-subject {
  font-weight: 600;
}

.mail-badge {
  display: inline-flex;
  align-items: center;
  min-height: 24px;
  padding: 0 0.5rem;
  border-radius: 999px;
  background: var(--accent-soft);
  color: var(--accent-strong);
  font-size: 0.76rem;
  font-weight: 700;
  white-space: nowrap;
}

.mail-preview {
  font-size: 0.92rem;
  line-height: 1.45;
}

.reader-head {
  display: flex;
  justify-content: space-between;
  gap: 1rem;
  align-items: start;
}

.reader-head h2,
.panel-head h2,
.section-head h3,
.shortcut-dialog h2 {
  margin: 0;
}

kbd {
  font: inherit;
  font-size: 0.8rem;
  font-weight: 700;
  padding: 0.08rem 0.42rem;
  border-radius: 6px;
  border: 1px solid var(--border);
  background: #fff;
  color: var(--text);
}

.reader-chip-row {
  display: flex;
  flex-wrap: wrap;
  gap: 0.55rem;
}

.reader-chip {
  display: inline-flex;
  align-items: center;
  min-height: 30px;
  padding: 0 0.7rem;
  border-radius: 999px;
  background: var(--surface-alt);
  border: 1px solid var(--border);
  color: var(--muted);
  font-size: 0.84rem;
  white-space: nowrap;
}

.reader-time {
  font-size: 0.92rem;
  color: var(--muted);
  white-space: nowrap;
}

.reader-meta {
  grid-template-columns: repeat(2, minmax(0, 1fr));
  padding: 1rem;
  border-radius: 8px;
  background: var(--surface-alt);
  border: 1px solid var(--border);
}

.reader-section {
  padding-top: 0.2rem;
}

.attachment-list {
  list-style: none;
  margin: 0;
  padding: 0;
  display: grid;
  gap: 0.6rem;
}

.attachment-row {
  display: grid;
  grid-template-columns: 56px minmax(0, 1fr) auto;
  align-items: center;
  gap: 1rem;
  padding: 0.75rem 0.9rem;
  border: 1px solid var(--border);
  border-radius: 8px;
  background: #fff;
}

.attachment-kind {
  width: 56px;
  min-width: 56px;
  min-height: 44px;
  border-radius: 8px;
  display: inline-flex;
  align-items: center;
  justify-content: center;
  background: var(--accent-soft);
  color: var(--accent-strong);
  font-size: 0.78rem;
  font-weight: 700;
  text-transform: uppercase;
}

.attachment-copy {
  min-width: 0;
  display: grid;
  gap: 0.18rem;
}

.attachment-copy strong,
.attachment-copy span {
  min-width: 0;
  overflow: hidden;
  text-overflow: ellipsis;
  white-space: nowrap;
}

.attachment-copy span {
  color: var(--muted);
  font-size: 0.88rem;
}

.attachment-download {
  display: inline-flex;
  align-items: center;
  justify-content: center;
  min-height: 40px;
  padding: 0 0.85rem;
  border-radius: 8px;
  border: 1px solid var(--border);
  background: var(--surface-alt);
  color: var(--text);
  font-weight: 600;
  white-space: nowrap;
}

.attachment-download:hover {
  text-decoration: none;
  background: var(--accent-soft);
  border-color: #a9c2f4;
}

.body-toggle {
  display: inline-flex;
  gap: 0.5rem;
}

.body-toggle-btn {
  min-width: 82px;
}

.body-toggle-active {
  background: var(--accent-soft);
  color: var(--accent-strong);
  border-color: #a9c2f4;
}

.body-panel {
  display: none;
  border: 1px solid var(--border);
  border-radius: 8px;
  background: #fff;
  padding: 1rem;
  overflow: auto;
}

.body-panel-active {
  display: block;
}

.body-plain {
  margin: 0;
  white-space: pre-wrap;
  font-family: ui-monospace, SFMono-Regular, Consolas, monospace;
  line-height: 1.5;
}

.empty-state {
  min-height: 220px;
  padding: 1.2rem;
  border: 1px dashed var(--border-strong);
  border-radius: 8px;
  background: linear-gradient(180deg, rgba(247, 250, 254, 0.9), rgba(238, 243, 250, 0.95));
  display: grid;
  place-items: center;
  align-content: center;
  text-align: center;
  gap: 0.35rem;
}

.list-empty {
  min-height: 320px;
}

.reader-empty {
  min-height: calc(100vh - 280px);
}

.shortcut-overlay {
  position: fixed;
  inset: 0;
  padding: 1rem;
  background: rgba(24, 40, 60, 0.45);
  display: grid;
  place-items: center;
  z-index: 40;
}

.shortcut-dialog {
  width: min(100%, 560px);
}

.shortcut-list {
  grid-template-columns: 1fr 1fr;
}

.shortcut-list div {
  padding: 0.8rem;
  border: 1px solid var(--border);
  border-radius: 8px;
  background: #fff;
}

.shortcut-list dt {
  display: flex;
  flex-wrap: wrap;
  gap: 0.35rem;
}

.shortcut-list dd {
  color: var(--muted);
  line-height: 1.45;
}

code {
  font: inherit;
  font-family: ui-monospace, SFMono-Regular, Consolas, monospace;
  font-size: 0.9em;
  padding: 0.08rem 0.36rem;
  border-radius: 6px;
  background: rgba(44, 107, 237, 0.08);
  color: var(--accent-strong);
}

@media (max-width: 1240px) {
  .action-strip,
  .workspace-grid {
    grid-template-columns: 1fr;
  }

  .split-workspace {
    grid-template-columns: 1fr;
    gap: 1rem;
  }

  .split-resizer {
    display: none;
  }

  .overview-panel,
  .list-panel,
  .reader-card,
  .reader-empty,
  .split-resizer {
    min-height: auto;
  }
}

@media (max-width: 820px) {
  .app-shell {
    padding: 0.75rem;
    gap: 0.85rem;
  }

  .app-topbar,
  .action-strip,
  .overview-panel,
  .list-panel,
  .reader-card,
  .shortcut-dialog {
    padding: 0.85rem;
  }

  .app-topbar,
  .address-heading,
  .panel-head,
  .section-head,
  .mail-copy-top,
  .reader-head,
  .reader-meta,
  .compact-group,
  .thread-head,
  .thread-head-copy,
  .thread-meta,
  .list-toolbar,
  .shortcut-list {
    display: grid;
    grid-template-columns: 1fr;
  }

  .action-strip {
    position: sticky;
    top: 0;
    z-index: 10;
    background: rgba(255, 255, 255, 0.98);
    backdrop-filter: blur(10px);
  }

  .address-actions,
  .list-toolbar-actions,
  .quick-form button,
  .ghost-button,
  .body-toggle-btn,
  .attachment-download {
    width: 100%;
  }

  .topbar-badges,
  .address-actions,
  .body-toggle,
  .reader-chip-row,
  .list-toolbar-actions {
    justify-content: flex-start;
    flex-wrap: wrap;
  }

  .overview-list {
    grid-template-columns: 1fr 1fr;
    gap: 0.75rem;
  }

  .overview-list div,
  .reader-meta div,
  .shortcut-list div {
    padding: 0.75rem;
    border: 1px solid var(--border);
    border-radius: 8px;
    background: #fff;
  }

  .attachment-row {
    grid-template-columns: 1fr;
    justify-content: start;
  }

  .mail-row {
    grid-template-columns: 10px 40px minmax(0, 1fr);
    gap: 0.7rem;
    padding: 0.8rem;
  }

  .mail-preview {
    display: -webkit-box;
    -webkit-line-clamp: 2;
    -webkit-box-orient: vertical;
    overflow: hidden;
  }

  .mail-time,
  .thread-time {
    font-size: 0.82rem;
  }

  .thread-head {
    gap: 0.65rem;
  }

  .thread-toggle {
    grid-template-columns: 16px minmax(0, 1fr);
    gap: 0.65rem;
  }

  .thread-title-row,
  .thread-preview-row {
    display: grid;
    gap: 0.28rem;
  }

  .thread-preview {
    white-space: normal;
    display: -webkit-box;
    -webkit-line-clamp: 2;
    -webkit-box-orient: vertical;
  }

  .reader-time {
    white-space: normal;
  }
}

@media (max-width: 560px) {
  .app-topbar h1 {
    font-size: 1.65rem;
  }

  .topbar-copy {
    font-size: 0.95rem;
  }

  .action-strip {
    margin: 0 -0.1rem;
  }

  .overview-list,
  .shortcut-list {
    grid-template-columns: 1fr;
  }

  .address-box {
    min-height: 56px;
    font-size: 0.92rem;
    padding: 0.8rem;
  }

  .mail-title-row,
  .thread-head-copy {
    display: grid;
    gap: 0.35rem;
  }

  .mail-badge,
  .thread-count,
  .thread-chip {
    width: fit-content;
  }

  .thread-meta {
    gap: 0.45rem;
  }

  .body-toggle {
    display: grid;
    grid-template-columns: 1fr 1fr;
  }

  .reader-chip {
    min-height: 28px;
    font-size: 0.8rem;
  }
}