:root {
    --bg-color: #f5f5f5;
    --surface-color: #ffffff;
    --text-color: #333333;
    --text-muted: #666666;
    --border-color: #dddddd;
    --shadow-color: rgba(0, 0, 0, 0.05);
    --hover-bg: #f9f9f9;
    --active-bg: #e8f4f8;
    --active-border: #0066cc;
    --accent-color: #0066cc;
    --btn-secondary-bg: #f0f0f0;
    --btn-secondary-hover: #e8e8e8;
    --btn-secondary-text: #333333;
    --btn-secondary-border: #dddddd;
}

[data-theme="dark"] {
    --bg-color: #1a1a1a;
    --surface-color: #2d2d2d;
    --text-color: #f0f0f0;
    --text-muted: #cccccc;
    --border-color: #404040;
    --shadow-color: rgba(0, 0, 0, 0.3);
    --hover-bg: #3a3a3a;
    --active-bg: #4a6b7a;
    --active-border: #29d9c2;
    --accent-color: #29d9c2;
    --btn-secondary-bg: #404040;
    --btn-secondary-hover: #4a4a4a;
    --btn-secondary-text: #f0f0f0;
    --btn-secondary-border: #404040;
}

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

html, body {
    height: 100%;
}

body {
    font-family: -apple-system, BlinkMacSystemFont, 'Segoe UI', Roboto, Oxygen, Ubuntu, Cantarell, sans-serif;
    color: var(--text-color);
    background: var(--bg-color);
    display: flex;
    flex-direction: column;
    overflow: hidden;
}

.app-header {
    background: var(--surface-color);
    border-bottom: 1px solid var(--border-color);
    box-shadow: 0 2px 4px var(--shadow-color);
}

.app-header-row {
    display: flex;
    justify-content: space-between;
    align-items: center;
    padding: 0.9rem 1rem;
    max-width: 1600px;
    margin: 0 auto;
}

.app-title {
    display: flex;
    align-items: center;
    gap: 0.75rem;
}

.app-title img {
    width: 40px;
    height: 40px;
}

.app-title h1 {
    font-size: 1.3rem;
    line-height: 1;
}

.app-header-controls {
    display: flex;
    gap: 0.5rem;
}

.btn-secondary {
    background: var(--btn-secondary-bg);
    color: var(--btn-secondary-text);
    border: 1px solid var(--btn-secondary-border);
    border-radius: 4px;
    padding: 0.45rem 0.7rem;
    font-size: 0.82rem;
    cursor: pointer;
}

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

.app-header-link {
    text-decoration: none;
}

.container {
    display: flex;
    flex: 1;
    min-height: 0;
    max-width: 1600px;
    width: 100%;
    margin: 0 auto;
    background: var(--surface-color);
}

.docs-footer {
    border-top: 1px solid var(--border-color);
    background: var(--surface-color);
    color: var(--text-muted);
    padding: 0.55rem 1rem;
    font-size: 0.8rem;
}

.docs-footer p {
    max-width: 1600px;
    margin: 0 auto;
}

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

.docs-footer a:hover {
    text-decoration: underline;
}

.sidebar {
    width: 250px;
    min-width: 180px;
    border-right: 1px solid var(--border-color);
    overflow-y: auto;
    padding: 0.9rem 0;
}

.sidebar-section {
    margin-bottom: 0.8rem;
}

.compose-trigger {
    width: calc(100% - 2rem);
    margin: 0 1rem;
    padding: 0.6rem 0.75rem;
    border-radius: 4px;
    border: 1px solid var(--active-border);
    background: var(--surface-color);
    color: var(--active-border);
    font-size: 0.9rem;
    font-weight: 600;
    text-align: left;
    cursor: pointer;
}

.compose-trigger:hover,
.compose-trigger.active {
    background: var(--active-bg);
}

.folder-create-demo {
    margin-top: 0.5rem;
}

.sidebar-section-title {
    font-size: 0.75rem;
    font-weight: 600;
    text-transform: uppercase;
    color: var(--text-muted);
    padding: 0.5rem 1rem;
    letter-spacing: 0.4px;
}

.folder-item {
    display: flex;
    align-items: center;
    justify-content: space-between;
    gap: 0.6rem;
    margin: 0.1rem 0;
    padding: 0.75rem 1rem;
    border-left: 3px solid transparent;
    color: var(--text-color);
}

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

.folder-item.active {
    background: var(--active-bg);
    border-left-color: var(--active-border);
    color: var(--active-border);
    font-weight: 600;
}

.folder-badge {
    color: var(--accent-color);
    font-size: 0.9em;
    font-weight: 600;
}

.message-list-pane {
    width: 350px;
    border-right: 1px solid var(--border-color);
    display: flex;
    flex-direction: column;
    min-width: 220px;
}

.message-list-header {
    padding: 0.75rem 1rem 0.5rem;
    border-bottom: 1px solid var(--border-color);
}

.inbox-list-title h2 {
    font-size: 1rem;
    margin: 0 0 0.1rem;
}

.inbox-list-title p {
    margin: 0 0 0.5rem;
    font-size: 0.875rem;
    color: var(--text-muted);
}

.inbox-search-form {
    display: block;
}

.inbox-search-row {
    display: flex;
    gap: 0.3rem;
    align-items: center;
}

.inbox-filter-row {
    display: flex;
    gap: 0.35rem;
    align-items: center;
    margin-top: 0.35rem;
}

.text-small {
    font-size: 0.875rem;
}

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

.inbox-search-input {
    flex: 1;
    min-width: 0;
    padding: 0.35rem 0.5rem;
    font-size: 0.85rem;
    border: 1px solid var(--border-color);
    border-radius: 4px;
    background: var(--surface-color);
    color: var(--text-color);
}

.inbox-search-scope {
    padding: 0.35rem 0.3rem;
    font-size: 0.78rem;
    border: 1px solid var(--border-color);
    border-radius: 4px;
    background: var(--surface-color);
    color: var(--text-color);
    cursor: pointer;
    white-space: nowrap;
}

.inbox-search-submit {
    padding: 0.35rem 0.55rem;
    background: var(--accent-color);
    color: #fff;
    border: none;
    border-radius: 4px;
    cursor: pointer;
    font-size: 0.9rem;
    line-height: 1;
    flex-shrink: 0;
}

.inbox-search-submit:hover {
    opacity: 0.85;
}

.inbox-search-active {
    margin-top: 0.45rem;
    font-size: 0.82rem;
    color: var(--text-muted);
}

.inbox-search-active a {
    color: var(--accent-color);
    text-decoration: none;
}

.inbox-search-active a:hover {
    text-decoration: underline;
}

.message-list {
    overflow-y: auto;
    flex: 1;
}

.is-hidden {
    display: none;
}

.message-item {
    padding: 0.9rem 1rem;
    border-bottom: 1px solid var(--border-color);
    cursor: pointer;
}

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

.message-item.selected {
    background: var(--active-bg);
    border-left: 3px solid var(--active-border);
}

.message-item-header {
    display: flex;
    justify-content: space-between;
    gap: 0.5rem;
    margin-bottom: 0.35rem;
}

.message-item-sender {
    display: flex;
    align-items: center;
    gap: 0.45rem;
    font-size: 0.95rem;
    font-weight: 400;
}

.message-unread-dot {
    width: 0.5rem;
    height: 0.5rem;
    border-radius: 50%;
    background: var(--accent-color);
    flex: 0 0 auto;
}

.message-starred-marker {
    color: var(--accent-color);
    font-size: 0.85rem;
    line-height: 1;
}

.message-item-time,
.message-item-preview {
    color: var(--text-muted);
    font-size: 0.83rem;
    font-weight: 400;
}

.message-item-subject {
    margin-bottom: 0.3rem;
    font-size: 0.92rem;
    font-weight: 400;
}

.detail-pane {
    flex: 1;
    overflow-y: auto;
    padding: 0;
}

.detail-empty {
    color: var(--text-muted);
    display: flex;
    align-items: center;
    justify-content: center;
    height: 100%;
    text-align: center;
    padding: 1.25rem;
}

.detail-content {
    padding: 1.25rem;
}

.detail-header {
    border-bottom: 1px solid var(--border-color);
    margin-bottom: 1rem;
    padding-bottom: 0.9rem;
}

.detail-subject {
    font-size: 1.35rem;
    margin-bottom: 0.7rem;
}

.detail-meta {
    display: flex;
    flex-wrap: wrap;
    gap: 1.2rem;
    color: var(--text-muted);
    font-size: 0.9rem;
}

.detail-meta-label {
    display: block;
    text-transform: uppercase;
    font-size: 0.75rem;
    margin-bottom: 0.1rem;
    color: var(--text-muted);
    letter-spacing: 0.4px;
}

.detail-body {
    line-height: 1.6;
}

.compose-fragment {
    padding: 1.25rem;
}

.compose-form {
    margin-top: 1rem;
}

.form-group {
    margin-bottom: 0.9rem;
}

.form-group label {
    display: block;
    margin-bottom: 0.3rem;
    font-size: 0.85rem;
    color: var(--text-muted);
}

.compose-input,
.compose-textarea,
.compose-file-input {
    width: 100%;
    border: 1px solid var(--border-color);
    border-radius: 4px;
    background: var(--surface-color);
    color: var(--text-color);
    padding: 0.5rem 0.6rem;
    font-size: 0.9rem;
}

.compose-textarea {
    min-height: 180px;
    resize: vertical;
}

.compose-rich-editor {
    min-height: 220px;
    border: 1px solid var(--border-color);
    border-radius: 4px;
    overflow: hidden;
}

.compose-rich-editor .ql-toolbar.ql-snow {
    border: none;
    border-bottom: 1px solid var(--border-color);
    background: var(--surface-color);
}

.compose-rich-editor .ql-container.ql-snow {
    border: none;
    min-height: 170px;
    color: var(--text-color);
    background: var(--surface-color);
}

[data-theme="dark"] .compose-rich-editor .ql-stroke {
    stroke: var(--text-color);
}

[data-theme="dark"] .compose-rich-editor .ql-fill {
    fill: var(--text-color);
}

[data-theme="dark"] .compose-rich-editor .ql-picker {
    color: var(--text-color);
}

.compose-status {
    margin-bottom: 0.75rem;
    padding: 0.55rem 0.7rem;
    border: 1px solid var(--border-color);
    border-radius: 4px;
    font-size: 0.85rem;
}

.compose-status.success {
    border-color: #2f855a;
    color: #2f855a;
}

.message-actions-toolbar {
    display: flex;
    align-items: center;
    gap: 0.4rem;
    padding: 0.4rem 0.75rem;
    border-bottom: 1px solid var(--border-color);
    background: var(--surface-color);
    flex-shrink: 0;
    flex-wrap: wrap;
}

.message-actions-toolbar form {
    display: inline;
}

.msg-action-group {
    display: flex;
    align-items: center;
    flex-wrap: wrap;
    gap: 0.3rem;
}

.msg-action-group--right {
    margin-left: auto;
}

.msg-action-btn {
    padding: 0.28rem 0.6rem;
    font-size: 0.8rem;
    background: var(--surface-color);
    color: var(--text-color);
    border: 1px solid var(--border-color);
    border-radius: 4px;
    cursor: pointer;
    white-space: nowrap;
    line-height: 1.4;
}

.msg-action-btn:hover {
    background: var(--hover-bg);
    border-color: var(--active-border);
}

.msg-action-btn--active {
    color: var(--accent-color);
    border-color: var(--accent-color);
}

.msg-action-btn--destructive:hover {
    color: #cc0000;
    border-color: #cc0000;
    background: var(--hover-bg);
}

@media (max-width: 768px) {
    body {
        overflow: auto;
    }

    .container {
        display: block;
    }

    .sidebar,
    .message-list-pane,
    .detail-pane {
        width: 100%;
        min-width: 0;
        border-right: none;
        border-bottom: 1px solid var(--border-color);
    }

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

    .msg-action-group--right {
        margin-left: 0;
    }

    .compose-trigger {
        width: calc(100% - 1.2rem);
        margin: 0 0.6rem;
    }
}