:root {
  color-scheme: light dark;
  --bg-primary: #ffffff;
  --bg-sidebar: #fbfbfa;
  --text-primary: #37352f;
  --text-muted: #787774;
  --border-default: #edece9;
  --hover-bg: #f1f0ed;
  --accent-blue: #2383e2;
  --gray-bg: #f1f1ef;
  --green-bg: #edf3ec;
  --green-text: #0f7b6c;
  --blue-bg: #e7f3f8;
  --blue-text: #0b6e99;
  --orange-bg: #fbecdd;
  --orange-text: #d9730d;
  --red-bg: #fdebec;
  --red-text: #e03e3e;
  --shadow-soft: 0 1px 2px rgba(15, 15, 15, 0.1);
}

@media (prefers-color-scheme: dark) {
  :root {
    --bg-primary: #191919;
    --bg-sidebar: #202020;
    --text-primary: #e3e3e3;
    --text-muted: #9b9b9b;
    --border-default: #2f2f2f;
    --hover-bg: #2c2c2c;
    --accent-blue: #2eaadc;
    --gray-bg: #272727;
    --green-bg: #222d28;
    --green-text: #4dab9a;
    --blue-bg: #222e35;
    --blue-text: #529cca;
    --orange-bg: #382e25;
    --orange-text: #e78b3f;
    --red-bg: #3c2424;
    --red-text: #ff6b6b;
  }
}

* {
  box-sizing: border-box;
}

html,
body {
  margin: 0;
  min-height: 100%;
  background: var(--bg-primary);
  color: var(--text-primary);
  font-family: ui-sans-serif, -apple-system, BlinkMacSystemFont, "Segoe UI", Roboto, Helvetica, Arial, sans-serif, "Apple Color Emoji", "Segoe UI Emoji";
  font-size: 15px;
  line-height: 1.5;
  letter-spacing: 0;
}

button,
input,
select {
  font: inherit;
}

button {
  border: 0;
}

.app-shell {
  min-height: 100vh;
}

.login-page {
  min-height: 100vh;
  display: grid;
  place-items: center;
  padding: 48px 24px;
}

.login-canvas {
  width: min(720px, 100%);
}

.brand-mark {
  width: 54px;
  height: 54px;
  object-fit: contain;
  margin-bottom: 18px;
}

.page-title {
  margin: 0 0 8px;
  color: var(--text-primary);
  font-size: 40px;
  font-weight: 600;
  line-height: 1.2;
}

.muted {
  color: var(--text-muted);
}

.login-form {
  width: min(420px, 100%);
  margin-top: 28px;
}

.forgot-password-btn {
  width: 100%;
  margin-top: 10px;
}

.modal-panel .login-form {
  width: 100%;
  margin-top: 18px;
}

.field {
  display: block;
  margin-bottom: 12px;
}

.field span {
  display: block;
  margin-bottom: 4px;
  color: var(--text-muted);
  font-size: 12px;
  line-height: 1.4;
}

.input {
  width: 100%;
  min-height: 38px;
  padding: 7px 10px;
  border: 1px solid var(--border-default);
  border-radius: 4px;
  outline: none;
  background: var(--bg-primary);
  color: var(--text-primary);
}

.input:focus {
  border-color: var(--accent-blue);
  box-shadow: 0 0 0 2px color-mix(in srgb, var(--accent-blue), transparent 82%);
}

.select-list {
  min-height: 132px;
}

.compact-input {
  min-height: 32px;
  padding: 4px 8px;
}

.inline-field {
  display: flex;
  align-items: center;
  gap: 8px;
  color: var(--text-muted);
  font-size: 12px;
}

.inline-field span {
  white-space: nowrap;
}

.btn {
  min-height: 34px;
  display: inline-flex;
  align-items: center;
  justify-content: center;
  gap: 8px;
  padding: 6px 12px;
  border-radius: 4px;
  background: transparent;
  color: var(--text-primary);
  cursor: pointer;
}

.btn:hover {
  background: var(--hover-bg);
}

.btn-primary {
  width: 100%;
  background: var(--accent-blue);
  color: #ffffff;
  box-shadow: var(--shadow-soft);
}

.btn-primary:hover {
  background: color-mix(in srgb, var(--accent-blue), #000 10%);
}

.btn.active {
  background: var(--hover-bg);
}

.btn-compact {
  min-height: 30px;
  padding: 4px 8px;
}

.icon-btn {
  width: 34px;
  height: 34px;
  display: inline-grid;
  place-items: center;
  border-radius: 4px;
  background: transparent;
  color: var(--text-primary);
  cursor: pointer;
}

.icon-btn:hover {
  background: var(--hover-bg);
}

svg {
  width: 18px;
  height: 18px;
  display: block;
  fill: none;
  stroke: currentColor;
  stroke-width: 1.8;
  stroke-linecap: round;
  stroke-linejoin: round;
}

.callout {
  margin: 12px 0;
  padding: 16px;
  border-radius: 4px;
  background: var(--gray-bg);
  color: var(--text-primary);
}

.callout.error {
  background: var(--red-bg);
  color: var(--red-text);
}

.portal {
  min-height: 100vh;
  display: grid;
  grid-template-columns: 238px minmax(0, 1fr);
  background: var(--bg-primary);
}

.sidebar {
  min-height: 100vh;
  padding: 12px;
  background: var(--bg-sidebar);
  border-right: 1px solid var(--border-default);
}

.sidebar-head {
  display: flex;
  align-items: center;
  gap: 9px;
  padding: 6px 6px 12px;
}

.sidebar-head img {
  width: 30px;
  height: 30px;
  object-fit: contain;
}

.sidebar-title {
  margin: 0;
  font-size: 14px;
  font-weight: 600;
  line-height: 1.2;
}

.sidebar-subtitle {
  margin: 0;
  color: var(--text-muted);
  font-size: 12px;
  line-height: 1.4;
}

.nav {
  display: grid;
  gap: 2px;
  margin-top: 6px;
}

.nav-item {
  width: 100%;
  min-height: 30px;
  display: flex;
  align-items: center;
  gap: 8px;
  padding: 4px 8px;
  border-radius: 4px;
  background: transparent;
  color: var(--text-primary);
  text-align: left;
  cursor: pointer;
}

.nav-item:hover,
.nav-item.active {
  background: var(--hover-bg);
}

.nav-icon {
  width: 18px;
  color: var(--text-muted);
  display: inline-grid;
  place-items: center;
}

.content {
  min-width: 0;
  height: 100vh;
  overflow: hidden;
}

.page {
  width: min(1120px, 100%);
  height: 100vh;
  margin: 0 auto;
  padding: 56px 96px 80px;
  overflow: auto;
}

.page-classroom {
  width: min(1180px, 100%);
  padding-left: 48px;
}

.page.full {
  width: 100%;
}

.page-kicker {
  margin: 0 0 2px;
  color: var(--text-muted);
  font-size: 12px;
  line-height: 1.4;
}

.page-heading {
  margin: 0 0 8px;
  color: var(--text-primary);
  font-size: 40px;
  font-weight: 600;
  line-height: 1.2;
}

.section-title {
  margin: 28px 0 8px;
  font-size: 24px;
  font-weight: 600;
  line-height: 1.3;
}

.section-row {
  display: flex;
  align-items: end;
  justify-content: space-between;
  gap: 12px;
  margin-top: 28px;
}

.section-row .section-title {
  margin-top: 0;
}

.block-grid {
  display: grid;
  grid-template-columns: repeat(auto-fit, minmax(220px, 1fr));
  gap: 12px;
  margin: 20px 0;
}

.block {
  min-height: 86px;
  padding: 12px;
  border: 1px solid var(--border-default);
  border-radius: 4px;
  background: var(--bg-primary);
}

.block-label {
  margin: 0 0 6px;
  color: var(--text-muted);
  font-size: 12px;
  line-height: 1.4;
}

.block-value {
  margin: 0;
  font-size: 18px;
  font-weight: 600;
  line-height: 1.3;
}

.db {
  width: 100%;
  border: 1px solid var(--border-default);
  border-radius: 4px;
  overflow: hidden;
}

.db-row {
  display: grid;
  border-top: 1px solid var(--border-default);
}

.db-row:first-child {
  border-top: 0;
}

.db-cell {
  min-width: 0;
  padding: 8px 10px;
  border-left: 1px solid var(--border-default);
  overflow-wrap: anywhere;
}

.db-cell:first-child {
  border-left: 0;
}

.db-head {
  color: var(--text-muted);
  background: var(--bg-sidebar);
  font-size: 12px;
}

.badge {
  display: inline-flex;
  align-items: center;
  max-width: 100%;
  padding: 1px 6px;
  border-radius: 4px;
  background: var(--blue-bg);
  color: var(--blue-text);
  font-size: 12px;
  font-weight: 600;
  line-height: 1.4;
}

.badge.green {
  background: var(--green-bg);
  color: var(--green-text);
}

.badge.orange {
  background: var(--orange-bg);
  color: var(--orange-text);
}

.split {
  display: grid;
  grid-template-columns: minmax(210px, 280px) minmax(0, 1fr);
  gap: 18px;
  margin-top: 20px;
}

.classroom-topline {
  display: flex;
  align-items: end;
  justify-content: space-between;
  gap: 16px;
  margin-bottom: 18px;
}

.classroom-topline .page-heading {
  margin-bottom: 0;
}

.channel-tabs {
  display: flex;
  flex-wrap: wrap;
  justify-content: flex-end;
  align-items: center;
  gap: 8px;
  max-width: min(620px, 55vw);
}

.classroom-split {
  grid-template-columns: minmax(180px, 240px) minmax(0, 1fr);
  gap: 12px;
  margin-top: 0;
}

.subject-panel {
  max-height: calc(100vh - 186px);
}

.subject-panel .panel-line {
  padding: 7px 8px;
}

.subject-panel .badge {
  padding-inline: 5px;
}

.channel-panel {
  min-width: 0;
}

.panel {
  border: 1px solid var(--border-default);
  border-radius: 4px;
  overflow: hidden;
}

.independent-panel,
.panel,
.db,
.mail-list,
.detail-panel,
.calendar-panel,
.upcoming-panel,
.week-panel {
  max-height: min(68vh, 720px);
  overflow: auto;
}

.panel-line {
  width: 100%;
  display: flex;
  align-items: center;
  justify-content: space-between;
  gap: 10px;
  padding: 8px 10px;
  border-top: 1px solid var(--border-default);
  background: transparent;
  color: var(--text-primary);
  text-align: left;
  cursor: pointer;
}

.panel-line:first-child {
  border-top: 0;
}

.panel-line:hover,
.panel-line.active {
  background: var(--hover-bg);
}

.subject-row {
  display: grid;
  grid-template-columns: minmax(0, 1fr) auto;
  align-items: center;
  gap: 4px;
  padding: 4px;
  border-top: 1px solid var(--border-default);
}

.subject-row:first-child {
  border-top: 0;
}

.subject-row.active,
.subject-row:hover {
  background: var(--hover-bg);
}

.subject-name {
  min-width: 0;
  padding: 5px 4px;
  background: transparent;
  color: var(--text-primary);
  text-align: left;
  cursor: pointer;
}

.subject-name span {
  display: block;
  min-width: 0;
  overflow-wrap: anywhere;
  white-space: normal;
}

.subject-actions {
  display: inline-flex;
  align-items: center;
  gap: 2px;
}

.subject-actions .icon-btn {
  width: 28px;
  height: 28px;
}

.subject-actions .icon-btn.active {
  background: var(--bg-primary);
  color: var(--accent-blue);
}

.message {
  display: grid;
  grid-template-columns: 28px minmax(0, 1fr);
  gap: 10px;
  padding: 10px 0;
  border-top: 1px solid var(--border-default);
}

button.message {
  width: 100%;
  background: transparent;
  color: var(--text-primary);
  text-align: left;
  cursor: pointer;
}

button.message:hover,
button.message.active {
  background: var(--hover-bg);
}

.message:first-child {
  border-top: 0;
}

.avatar {
  width: 28px;
  height: 28px;
  display: grid;
  place-items: center;
  border-radius: 4px;
  background: var(--gray-bg);
  color: var(--text-muted);
  font-size: 12px;
  font-weight: 600;
}

.message-title {
  margin: 0;
  font-weight: 600;
}

.message-body {
  margin: 3px 0 0;
  color: var(--text-muted);
}

.toolbar {
  display: flex;
  flex-wrap: wrap;
  align-items: center;
  gap: 8px;
  margin: 16px 0;
}

.toolbar.tight {
  margin: 0;
}

.panel-title-row {
  display: flex;
  align-items: center;
  justify-content: space-between;
  gap: 12px;
  margin-bottom: 10px;
}

.panel-title-row h2,
.panel-title-row h3 {
  margin: 0;
}

.panel-title-row h3 {
  font-size: 16px;
  font-weight: 600;
}

.chart {
  width: 100%;
  height: 300px;
  display: block;
  border: 1px solid var(--border-default);
  border-radius: 4px;
  background: var(--bg-primary);
}

.mail-layout,
.calendar-layout {
  display: grid;
  grid-template-columns: minmax(260px, 0.9fr) minmax(0, 1.2fr);
  gap: 18px;
  margin-top: 20px;
}

.mail-list,
.detail-panel,
.calendar-panel,
.upcoming-panel {
  min-width: 0;
}

.detail-panel,
.calendar-panel,
.upcoming-panel {
  border: 1px solid var(--border-default);
  border-radius: 4px;
  padding: 16px;
}

.detail-panel .section-title,
.calendar-panel .section-title,
.upcoming-panel .section-title {
  margin-top: 0;
}

.calendar-weekdays,
.calendar-grid {
  display: grid;
  grid-template-columns: repeat(7, minmax(0, 1fr));
}

.calendar-toolbar {
  display: flex;
  align-items: center;
  justify-content: space-between;
  gap: 12px;
  margin-bottom: 8px;
}

.calendar-toolbar .section-title {
  margin: 0;
}

.calendar-actions,
.segmented {
  display: inline-flex;
  align-items: center;
  gap: 4px;
}

.segmented {
  padding: 2px;
  border: 1px solid var(--border-default);
  border-radius: 4px;
}

.calendar-weekdays {
  color: var(--text-muted);
  font-size: 12px;
  border: 1px solid var(--border-default);
  border-bottom: 0;
  background: var(--bg-sidebar);
}

.calendar-weekdays span {
  padding: 7px 8px;
  border-left: 1px solid var(--border-default);
}

.calendar-weekdays span:first-child {
  border-left: 0;
}

.calendar-grid {
  border: 1px solid var(--border-default);
}

.calendar-cell {
  min-height: 92px;
  padding: 7px;
  border-left: 1px solid var(--border-default);
  border-top: 1px solid var(--border-default);
}

.calendar-cell:nth-child(7n + 1) {
  border-left: 0;
}

.calendar-cell:nth-child(-n + 7) {
  border-top: 0;
}

.muted-cell {
  background: var(--bg-sidebar);
}

.calendar-day {
  margin-bottom: 6px;
  color: var(--text-muted);
  font-size: 12px;
}

.calendar-chip {
  margin-top: 4px;
  padding: 1px 6px;
  border-radius: 4px;
  background: var(--blue-bg);
  color: var(--blue-text);
  font-size: 12px;
  overflow: hidden;
  text-overflow: ellipsis;
  white-space: nowrap;
}

.calendar-chip.local {
  background: var(--green-bg);
  color: var(--green-text);
}

.week-panel {
  border: 1px solid var(--border-default);
  border-radius: 4px;
  overflow: auto;
}

.calendar-panel,
.upcoming-panel,
.week-panel {
  max-height: calc(100vh - 230px);
}

.week-head,
.week-row {
  min-width: 760px;
  display: grid;
  grid-template-columns: 72px repeat(7, minmax(96px, 1fr));
}

.week-head {
  position: sticky;
  top: 0;
  z-index: 1;
  background: var(--bg-sidebar);
  color: var(--text-muted);
  font-size: 12px;
}

.week-head span,
.week-time,
.week-cell {
  padding: 8px;
  border-left: 1px solid var(--border-default);
  border-top: 1px solid var(--border-default);
}

.week-head span:first-child,
.week-time {
  border-left: 0;
}

.week-head span {
  border-top: 0;
}

.week-time {
  color: var(--text-muted);
  font-size: 12px;
  background: var(--bg-sidebar);
}

.week-cell {
  min-height: 58px;
}

.event-form {
  margin-top: 18px;
  padding: 16px;
  border: 1px solid var(--border-default);
  border-radius: 4px;
}

.event-form .section-title {
  margin-top: 0;
}

.event-form-grid {
  display: grid;
  grid-template-columns: repeat(2, minmax(0, 1fr));
  gap: 12px;
}

.event-line {
  padding: 10px 0;
  border-top: 1px solid var(--border-default);
}

.event-line:first-of-type {
  border-top: 0;
}

.modal-layer {
  position: fixed;
  inset: 0;
  z-index: 40;
  display: grid;
  place-items: center;
  padding: 24px;
  background: color-mix(in srgb, var(--bg-primary), transparent 14%);
  backdrop-filter: blur(4px);
}

.modal-panel {
  width: min(480px, 100%);
  padding: 18px;
  border: 1px solid var(--border-default);
  border-radius: 4px;
  background: var(--bg-primary);
  box-shadow: var(--shadow-soft);
}

.modal-actions {
  display: flex;
  justify-content: flex-end;
  gap: 8px;
  margin-top: 12px;
}

.modal-actions .btn-primary {
  width: auto;
}

.compose-fab {
  position: fixed;
  right: 28px;
  bottom: 28px;
  z-index: 25;
  width: 58px;
  height: 58px;
  border: 0;
  border-radius: 50%;
  background: var(--accent-primary);
  color: #fff;
  font-size: 32px;
  line-height: 1;
  cursor: pointer;
  box-shadow: 0 10px 28px rgba(0, 0, 0, .3);
}

.compose-fab:hover { filter: brightness(1.08); }
.compose-panel { width: min(620px, 100%); }
.compose-form { margin-top: 18px; }
.compose-message { min-height: 180px; resize: vertical; }
.compose-card-head{display:flex;align-items:flex-start;justify-content:space-between;gap:18px;padding-bottom:14px;border-bottom:1px solid var(--border-default)}.compose-card-head h2,.compose-card-head p{margin:0}.compose-card-form{display:grid;gap:0}.compose-card-form .field{margin:0;padding:13px 0;border-bottom:1px solid var(--border-default)}.compose-card-form .field>span{font-size:12px}.compose-card-form .input{border:0;background:transparent;padding:8px 0;box-shadow:none}.compose-body textarea{min-height:210px}.compose-card-actions{display:flex;align-items:center;gap:12px;padding-top:14px}.compose-card-actions .btn-primary{margin-left:auto}.attach-button{display:inline-flex;align-items:center;gap:8px;padding:9px 12px;border:1px solid var(--border-default);border-radius:999px;cursor:pointer}.compose-files,.mail-attachments{display:flex;flex-wrap:wrap;gap:8px;padding-top:12px}.compose-file-chip,.mail-attachment{display:inline-flex;align-items:center;gap:8px;padding:8px 11px;border:1px solid var(--border-default);border-radius:10px;background:var(--bg-primary);color:var(--text-primary)}.mail-attachment{text-align:left;cursor:pointer}.mail-attachment span:last-child{display:grid}.mail-attachment small{color:var(--text-muted)}@media(max-width:600px){.compose-panel{width:100%;height:100dvh;border-radius:0}.compose-body textarea{min-height:38dvh}.compose-card-actions{position:sticky;bottom:0;background:var(--bg-primary);flex-wrap:wrap}.compose-card-actions .muted{display:none}}

.mobile-channel-mode-nav { display: none; }

.subject-directory-list { margin-top: 22px; border: 1px solid var(--border-default); border-radius: 12px; overflow: hidden; }
.subject-directory-row { width: 100%; display: flex; align-items: center; justify-content: space-between; gap: 16px; padding: 17px 18px; border: 0; border-bottom: 1px solid var(--border-default); background: var(--bg-primary); color: var(--text-primary); text-align: left; cursor: pointer; }
.subject-directory-row:last-child { border-bottom: 0; }
.subject-directory-row:hover { background: var(--hover-bg); }
.subject-directory-row span { min-width: 0; display: grid; gap: 4px; }
.subject-directory-row small { color: var(--text-muted); }
.subject-directory-row svg { flex: 0 0 20px; width: 20px; height: 20px; }

.mobile-file-list { display: grid; margin-top: 10px; }
.mobile-file-row { width: 100%; display: grid; grid-template-columns: 38px minmax(0, 1fr) 20px; align-items: center; gap: 10px; padding: 14px 4px; border: 0; border-bottom: 1px solid var(--border-default); background: transparent; color: var(--text-primary); text-align: left; cursor: pointer; }
.mobile-file-row:last-child { border-bottom: 0; }
.mobile-file-row > span:nth-child(2) { min-width: 0; display: grid; gap: 3px; }
.mobile-file-row strong { overflow: hidden; text-overflow: ellipsis; white-space: nowrap; }
.mobile-file-row small { color: var(--text-muted); }
.mobile-file-row > svg { width: 18px; height: 18px; color: var(--text-muted); }

.mail-filters { display: inline-flex; gap: 3px; margin: 0 0 14px; padding: 3px; border: 1px solid var(--border-default); border-radius: 8px; background: var(--bg-sidebar); }
.mail-filters button { min-height: 32px; padding: 5px 12px; border: 0; border-radius: 6px; background: transparent; color: var(--text-muted); cursor: pointer; }
.mail-filters button.active { background: var(--bg-primary); color: var(--text-primary); box-shadow: var(--shadow-soft); }
.message-title { display: flex; align-items: center; justify-content: space-between; gap: 8px; }
.mail-direction { display: inline-flex; flex: 0 0 auto; align-items: center; padding: 2px 7px; border-radius: 999px; font-size: 10px; font-weight: 700; letter-spacing: .02em; }
.mail-direction.received { background: var(--blue-bg); color: var(--blue-text); }
.mail-direction.sent { background: var(--green-bg); color: var(--green-text); }
.mail-route { display: flex; align-items: center; gap: 7px; flex-wrap: wrap; }
.mail-party strong { color: var(--text-muted); font-weight: 600; }
.mail-arrow { color: var(--text-muted); }

.settings-list {
  overflow: hidden;
  border: 1px solid var(--border-default);
  border-radius: 12px;
  background: var(--bg-primary);
}

.settings-row {
  display: flex;
  align-items: center;
  justify-content: space-between;
  gap: 24px;
  padding: 18px 20px;
  border-bottom: 1px solid var(--border-default);
}

.settings-row:last-child { border-bottom: 0; }
.settings-row strong { display: block; margin-bottom: 4px; }
.settings-row p { margin: 0; color: var(--text-muted); font-size: 13px; }
.settings-control { display: flex; align-items: center; justify-content: flex-end; gap: 10px; flex-wrap: wrap; }
.settings-control .input { width: min(300px, 100%); }
.switch-label { display: inline-flex; align-items: center; gap: 7px; white-space: nowrap; font-size: 13px; }

.classroom-workspace {
  display: grid;
  grid-template-columns: minmax(0, 0.95fr) minmax(360px, 1.25fr);
  gap: 12px;
}

.classroom-workspace.single-panel {
  grid-template-columns: minmax(0, 1fr);
}

.chat-panel,
.file-panel {
  height: calc(100vh - 234px);
  min-height: 460px;
  padding: 14px;
  border: 1px solid var(--border-default);
  border-radius: 4px;
  background: var(--bg-primary);
  display: flex;
  flex-direction: column;
  overflow: hidden;
}

.chat-scroll {
  min-height: 0;
  flex: 1;
  overflow: auto;
  padding-right: 4px;
}

.chat-composer {
  display: grid;
  grid-template-columns: minmax(0, 1fr) 38px;
  gap: 8px;
  padding-top: 10px;
  border-top: 1px solid var(--border-default);
}

.slash-menu {
  margin: 8px 0;
  border: 1px solid var(--border-default);
  border-radius: 4px;
  overflow: hidden;
  background: var(--bg-primary);
  box-shadow: var(--shadow-soft);
}

.slash-menu button {
  width: 100%;
  display: grid;
  grid-template-columns: 74px minmax(0, 1fr);
  gap: 10px;
  padding: 8px 10px;
  border-top: 1px solid var(--border-default);
  background: transparent;
  color: var(--text-primary);
  text-align: left;
  cursor: pointer;
}

.slash-menu button:first-child {
  border-top: 0;
}

.slash-menu button:hover {
  background: var(--hover-bg);
}

.slash-menu span {
  color: var(--text-muted);
}

.drop-zone {
  position: absolute;
  inset: 14px;
  z-index: 6;
  display: none;
  place-items: center;
  gap: 6px;
  padding: 16px;
  border: 1px dashed var(--border-default);
  border-radius: 4px;
  background: color-mix(in srgb, var(--blue-bg), var(--bg-primary) 16%);
  color: var(--text-muted);
  text-align: center;
}

.drop-zone.visible {
  display: grid;
}

.drop-zone.visible {
  border-color: var(--accent-blue);
  color: var(--blue-text);
}

.file-panel {
  position: relative;
}

.file-manager {
  min-height: 0;
  height: 100%;
  flex: 1;
  overflow: hidden;
  display: grid;
  grid-template-columns: minmax(160px, 220px) minmax(0, 1fr);
  gap: 12px;
}

.folder-tree {
  height: 100%;
  min-height: 0;
  overflow: auto;
  padding-right: 4px;
  border-right: 1px solid var(--border-default);
}

.folder-tree-row {
  width: 100%;
  min-height: 32px;
  display: flex;
  align-items: center;
  gap: 8px;
  padding: 5px 8px;
  border-radius: 4px;
  background: transparent;
  color: var(--text-primary);
  text-align: left;
  cursor: pointer;
}

.folder-tree-row:hover,
.folder-tree-row.active {
  background: var(--hover-bg);
}

.folder-tree-row.file-row {
  color: var(--text-muted);
}

.folder-tree-row span {
  min-width: 0;
  overflow: hidden;
  text-overflow: ellipsis;
  white-space: nowrap;
}

.file-browser {
  min-width: 0;
  min-height: 0;
  overflow: hidden;
  display: flex;
  flex-direction: column;
}

.breadcrumbs {
  min-height: 30px;
  display: flex;
  align-items: center;
  gap: 4px;
  margin-bottom: 8px;
  color: var(--text-muted);
  font-size: 12px;
}

.breadcrumbs button {
  padding: 3px 5px;
  border-radius: 4px;
  background: transparent;
  color: var(--text-primary);
  cursor: pointer;
}

.breadcrumbs button:hover {
  background: var(--hover-bg);
}

.breadcrumbs svg {
  width: 14px;
  height: 14px;
}

.file-grid {
  min-height: 0;
  height: 100%;
  flex: 1;
  display: grid;
  grid-template-columns: repeat(auto-fill, minmax(172px, 1fr));
  align-content: start;
  gap: 10px;
  overflow: auto;
  padding-right: 4px;
}

.file-card {
  position: relative;
  min-width: 0;
  padding: 12px;
  border: 1px solid var(--border-default);
  border-radius: 4px;
  background: var(--bg-primary);
}

.file-card.drag-target {
  border-color: var(--accent-blue);
  background: var(--blue-bg);
}

.file-open {
  display: block;
  padding: 0;
  background: transparent;
  color: inherit;
  cursor: pointer;
}

.file-icon {
  width: 38px;
  height: 38px;
  display: grid;
  place-items: center;
  margin-bottom: 10px;
  border-radius: 4px;
  background: var(--gray-bg);
  color: var(--text-muted);
}

.file-icon.folder {
  background: var(--orange-bg);
  color: var(--orange-text);
}

.file-meta {
  min-height: 52px;
}

.file-actions {
  display: flex;
  gap: 4px;
  justify-content: flex-end;
  margin-top: 8px;
}

.file-menu {
  position: absolute;
  right: 8px;
  bottom: 42px;
  z-index: 3;
  min-width: 156px;
  overflow: hidden;
  border: 1px solid var(--border-default);
  border-radius: 4px;
  background: var(--bg-primary);
  box-shadow: var(--shadow-soft);
}

.file-menu button {
  width: 100%;
  min-height: 32px;
  display: flex;
  align-items: center;
  gap: 8px;
  padding: 6px 9px;
  border-top: 1px solid var(--border-default);
  background: transparent;
  color: var(--text-primary);
  text-align: left;
  cursor: pointer;
}

.file-menu button:first-child {
  border-top: 0;
}

.file-menu button:hover {
  background: var(--hover-bg);
}

.file-menu button.danger {
  color: var(--red-text);
}

.icon-btn.danger {
  color: var(--red-text);
}

.empty {
  padding: 16px;
  border-radius: 4px;
  background: var(--gray-bg);
  color: var(--text-muted);
}

.mobile-topbar {
  display: none;
}

@media (max-width: 860px) {
  .portal {
    grid-template-columns: 1fr;
  }

  .mobile-topbar {
    position: sticky;
    top: 0;
    z-index: 30;
    display: flex;
    align-items: center;
    justify-content: space-between;
    gap: 12px;
    padding: 10px 14px;
    background: var(--bg-sidebar);
    border-bottom: 1px solid var(--border-default);
  }

  .mobile-topbar #openNav { display: none; }

  .sidebar {
    position: fixed;
    inset: auto 0 0 0;
    z-index: 50;
    width: 100%;
    min-height: 0;
    padding: 6px 8px max(6px, env(safe-area-inset-bottom));
    border: 0;
    border-top: 1px solid var(--border-default);
    transform: none;
  }

  .sidebar-head { display: none; }
  .nav { display: flex; gap: 4px; margin: 0; overflow-x: auto; scrollbar-width: none; }
  .nav::-webkit-scrollbar { display: none; }
  .nav-item { flex: 1 0 64px; min-height: 52px; flex-direction: column; justify-content: center; gap: 2px; padding: 4px; text-align: center; }
  .nav-icon { width: 20px; }
  .nav-label { display: block; font-size: 10px; white-space: nowrap; }

  .drawer-backdrop {
    position: fixed;
    inset: 0;
    z-index: 45;
    background: rgba(15, 15, 15, 0.22);
  }

  .content {
    height: calc(100vh - 55px);
    min-height: calc(100vh - 55px);
    overflow: hidden;
    padding-bottom: 66px;
  }

  .page {
    height: 100%;
    padding: 32px 24px 64px;
  }

  .settings-row { align-items: stretch; flex-direction: column; gap: 12px; }
  .settings-control { align-items: stretch; flex-direction: column; }
  .settings-control .input { width: 100%; }

  .page-heading,
  .page-title {
    font-size: 30px;
    line-height: 1.3;
  }

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

  .classroom-topline {
    align-items: stretch;
    flex-direction: column;
  }

  .channel-tabs {
    justify-content: flex-start;
    max-width: none;
  }

  .classroom-split {
    grid-template-columns: 1fr;
    gap: 0;
  }

  .page-classroom {
    padding-bottom: 82px;
  }

  .page-classroom .subject-panel {
    display: flex;
    max-height: none;
    overflow-x: auto;
    overflow-y: hidden;
    margin-bottom: 12px;
    background: var(--bg-sidebar);
    scrollbar-width: none;
  }

  .page-classroom .subject-panel::-webkit-scrollbar {
    display: none;
  }

  .page-classroom .subject-row {
    flex: 0 0 128px;
    display: flex;
    align-items: center;
    justify-content: center;
    flex-direction: column;
    gap: 3px;
    min-height: 46px;
    padding: 6px 8px;
    border-top: 0;
    border-left: 1px solid var(--border-default);
  }

  .page-classroom .subject-row:first-child {
    border-left: 0;
  }

  .page-classroom .subject-name {
    width: 100%;
    padding: 2px;
    font-size: 12px;
    font-weight: 600;
    text-align: center;
  }

  .page-classroom .subject-name span {
    overflow: hidden;
    text-overflow: ellipsis;
    white-space: nowrap;
  }

  .page-classroom .subject-actions .icon-btn {
    display: none;
  }

  .mobile-channel-mode-nav {
    position: fixed;
    right: 0;
    bottom: 0;
    left: 0;
    z-index: 49;
    display: grid;
    grid-template-columns: 1fr 1fr;
    padding: 7px 12px;
    border-top: 1px solid var(--border-default);
    background: var(--bg-sidebar);
    box-shadow: 0 -6px 20px rgba(0, 0, 0, 0.08);
    padding-bottom: max(7px, env(safe-area-inset-bottom));
  }

  .mobile-channel-mode-nav button {
    min-height: 48px;
    display: flex;
    align-items: center;
    justify-content: center;
    gap: 8px;
    border: 0;
    border-radius: 8px;
    background: transparent;
    color: var(--text-muted);
    cursor: pointer;
  }

  .mobile-channel-mode-nav button.active {
    background: var(--hover-bg);
    color: var(--accent-blue);
    font-weight: 600;
  }

  .mobile-channel-mode-nav svg {
    width: 20px;
    height: 20px;
  }

  .portal.channel-open .mobile-topbar,
  .portal.channel-open > .sidebar {
    display: none;
  }

  .portal.channel-open .content {
    height: 100vh;
    min-height: 100vh;
    padding-bottom: 0;
  }

  .portal.channel-open .page-classroom {
    height: 100vh;
    padding: 0 0 68px;
  }

  .mobile-channel-screen {
    height: 100%;
    display: flex;
    flex-direction: column;
    overflow: hidden;
  }

  .mobile-channel-header {
    flex: 0 0 auto;
    display: flex;
    align-items: center;
    gap: 10px;
    padding: 10px 14px;
    border-bottom: 1px solid var(--border-default);
    background: var(--bg-sidebar);
  }

  .mobile-channel-header .icon-btn svg { transform: rotate(180deg); }
  .mobile-channel-header .page-kicker { margin-bottom: 1px; }
  .mobile-channel-title { margin: 0; font-size: 18px; line-height: 1.2; }

  .mobile-channel-content {
    min-height: 0;
    flex: 1;
    overflow: hidden;
  }

  .mobile-channel-content .classroom-workspace,
  .mobile-channel-content .chat-panel,
  .mobile-channel-content .file-panel {
    height: 100%;
    min-height: 0;
    max-height: none;
    border: 0;
    border-radius: 0;
  }

  .mobile-channel-content .mobile-files-panel {
    overflow-y: auto;
    padding: 16px;
  }

  .mobile-channel-content .chat-panel {
    padding-bottom: 70px;
  }

  .mobile-channel-content .chat-composer {
    position: fixed;
    right: 0;
    bottom: calc(62px + env(safe-area-inset-bottom));
    left: 0;
    z-index: 48;
    padding: 8px 12px;
    border-top: 1px solid var(--border-default);
    background: var(--bg-primary);
  }

  .mail-layout,
  .calendar-layout,
  .classroom-workspace {
    grid-template-columns: 1fr;
  }

  .independent-panel,
  .panel,
  .db,
  .mail-list,
  .detail-panel,
  .calendar-panel,
  .upcoming-panel,
  .week-panel {
    max-height: 62vh;
  }

  .chat-panel,
  .file-panel {
    height: auto;
    min-height: 390px;
  }

  .file-manager {
    grid-template-columns: 1fr;
  }

  .folder-tree {
    max-height: 160px;
    border-right: 0;
    border-bottom: 1px solid var(--border-default);
    padding: 0 0 8px;
  }

  .calendar-toolbar {
    align-items: stretch;
    flex-direction: column;
  }

  .calendar-actions {
    flex-wrap: wrap;
  }

  .event-form-grid {
    grid-template-columns: 1fr;
  }

  .db {
    overflow-x: auto;
  }

  .db-row {
    min-width: 620px;
  }
}