:root {
    color-scheme: light dark;

    --bg: #f6f7f9;
    --surface: #ffffff;
    --surface-hover: #f2f4f7;
    --border: #e3e6ea;
    --border-strong: #d4d8de;
    --text: #1a1d21;
    --text-muted: #6b7280;
    --accent: #2f6fed;
    --accent-contrast: #ffffff;
    --danger: #d43a2f;
    --danger-contrast: #ffffff;
    --shadow: 0 1px 2px rgba(16, 24, 40, 0.06), 0 1px 3px rgba(16, 24, 40, 0.08);
    --radius: 12px;

    font-family: -apple-system, BlinkMacSystemFont, "Segoe UI", Roboto, sans-serif;
    font-size: 15px;
    line-height: 1.5;
}

@media (prefers-color-scheme: dark) {
    :root {
        --bg: #0f1115;
        --surface: #171a20;
        --surface-hover: #1e2229;
        --border: #262b33;
        --border-strong: #333a44;
        --text: #e7eaee;
        --text-muted: #9aa3af;
        --accent: #5b8dff;
        --accent-contrast: #0f1115;
        --danger: #f0574a;
        --danger-contrast: #0f1115;
        --shadow: none;
    }
}

* {
    box-sizing: border-box;
}

body {
    margin: 0;
    background: var(--bg);
    color: var(--text);
    -webkit-font-smoothing: antialiased;
}

a {
    color: inherit;
    text-decoration: none;
}

/* --- controls --- */

button,
input {
    font: inherit;
}

button {
    border: 1px solid transparent;
    border-radius: 8px;
    padding: 9px 16px;
    font-weight: 600;
    cursor: pointer;
    transition: background 0.12s ease, border-color 0.12s ease, opacity 0.12s ease;
}

button:not(.secondary):not(.danger) {
    background: var(--accent);
    color: var(--accent-contrast);
}

button:not(.secondary):not(.danger):hover {
    opacity: 0.9;
}

.secondary {
    background: var(--surface);
    color: var(--text);
    border-color: var(--border-strong);
}

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

.danger {
    background: transparent;
    color: var(--danger);
    border-color: var(--border-strong);
}

.danger:hover {
    background: var(--danger);
    color: var(--danger-contrast);
    border-color: var(--danger);
}

input {
    width: 100%;
    border: 1px solid var(--border-strong);
    border-radius: 8px;
    padding: 11px 13px;
    background: var(--bg);
    color: var(--text);
    transition: border-color 0.12s ease, box-shadow 0.12s ease;
}

input:focus {
    outline: none;
    border-color: var(--accent);
    box-shadow: 0 0 0 3px color-mix(in srgb, var(--accent) 20%, transparent);
}

/* --- login --- */

.centered {
    min-height: 100vh;
    display: grid;
    place-items: center;
    padding: 20px;
}

.card,
.message-card {
    width: 100%;
    max-width: 820px;
    background: var(--surface);
    border: 1px solid var(--border);
    border-radius: var(--radius);
    padding: 28px;
    box-shadow: var(--shadow);
}

.login-card {
    max-width: 400px;
    padding: 32px;
}

.login-card h1 {
    margin: 0 0 4px;
    font-size: 26px;
    letter-spacing: -0.02em;
}

.login-card form {
    display: grid;
    gap: 14px;
    margin-top: 20px;
}

.login-card label {
    font-size: 13px;
    font-weight: 600;
    color: var(--text-muted);
}

.login-card button {
    margin-top: 4px;
    padding: 11px;
}

.muted {
    color: var(--text-muted);
    margin: 0;
}

.error {
    color: var(--danger);
    margin: 12px 0 0;
    font-size: 14px;
}

/* --- top bar --- */

.topbar {
    position: sticky;
    top: 0;
    z-index: 10;
    min-height: 60px;
    padding: 12px 24px;
    background: color-mix(in srgb, var(--surface) 85%, transparent);
    backdrop-filter: saturate(1.4) blur(10px);
    border-bottom: 1px solid var(--border);
    display: flex;
    align-items: center;
    justify-content: space-between;
    gap: 16px;
}

.topbar h1 {
    margin: 0;
    font-size: 19px;
    font-weight: 700;
    letter-spacing: -0.01em;
}

.actions {
    display: flex;
    gap: 8px;
}

.back {
    font-weight: 600;
    color: var(--text-muted);
    transition: color 0.12s ease;
}

.back:hover {
    color: var(--text);
}

/* --- layout --- */

.container {
    width: min(880px, calc(100% - 32px));
    margin: 28px auto;
}

/* --- mail list --- */

.mail-list {
    border: 1px solid var(--border);
    border-radius: var(--radius);
    overflow: hidden;
    background: var(--surface);
    box-shadow: var(--shadow);
}

.mail-row {
    display: flex;
    align-items: center;
    gap: 14px;
    padding: 15px 18px;
    border-bottom: 1px solid var(--border);
    transition: background 0.1s ease;
}

.mail-row:last-child {
    border-bottom: 0;
}

.mail-row:hover {
    background: var(--surface-hover);
}

.mail-check {
    width: 17px;
    height: 17px;
    flex-shrink: 0;
    accent-color: var(--accent);
    cursor: pointer;
}

.mail-link {
    flex: 1;
    min-width: 0;
    display: flex;
    align-items: center;
    justify-content: space-between;
    gap: 20px;
}

/* selection toolbar */
.bulk-bar {
    display: flex;
    align-items: center;
    gap: 12px;
    padding: 5px 8px 5px 12px;
    margin-bottom: 8px;
    background: var(--surface);
    border: 1px solid var(--border);
    border-radius: 8px;
}

.bulk-bar .select-all {
    display: flex;
    align-items: center;
    gap: 7px;
    font-size: 13px;
    cursor: pointer;
}

.bulk-bar .select-all input {
    width: 15px;
    height: 15px;
    accent-color: var(--accent);
    cursor: pointer;
}

.bulk-bar #select-count {
    font-size: 13px;
}

.bulk-bar .danger {
    margin-left: auto;
    padding: 5px 11px;
    font-size: 13px;
    border-radius: 6px;
}

.mail-main {
    min-width: 0;
    display: grid;
    gap: 3px;
}

.mail-main strong {
    font-weight: 600;
}

.mail-main strong,
.mail-main span {
    overflow: hidden;
    text-overflow: ellipsis;
    white-space: nowrap;
}

.mail-main span,
.mail-row time {
    color: var(--text-muted);
    font-size: 13px;
}

.mail-row time {
    flex-shrink: 0;
    font-variant-numeric: tabular-nums;
}

/* --- message view --- */

.message-card h1 {
    margin: 0 0 20px;
    font-size: 24px;
    line-height: 1.3;
    letter-spacing: -0.01em;
}

.headers {
    display: grid;
    grid-template-columns: 60px 1fr;
    gap: 8px 16px;
    padding: 16px;
    margin: 0;
    background: var(--bg);
    border: 1px solid var(--border);
    border-radius: 10px;
    font-size: 14px;
}

.headers dt {
    color: var(--text-muted);
    font-weight: 500;
}

.headers dd {
    margin: 0;
    overflow-wrap: anywhere;
}

.body {
    margin: 24px 0 0;
    white-space: pre-wrap;
    overflow-wrap: anywhere;
    font-family: inherit;
    font-size: 15px;
    line-height: 1.7;
}

.attachments {
    margin-top: 22px;
    padding: 16px;
    background: var(--bg);
    border: 1px solid var(--border);
    border-radius: 10px;
    font-size: 14px;
}

.attachments strong {
    display: block;
    margin-bottom: 8px;
}

.attachments ul {
    margin: 0;
    padding-left: 18px;
    color: var(--text-muted);
}

/* --- empty state --- */

.empty {
    text-align: center;
    padding: 100px 20px;
    color: var(--text-muted);
}

.empty h2 {
    font-weight: 500;
    font-size: 17px;
}

@media (max-width: 640px) {
    .topbar,
    .container {
        padding-left: 16px;
        padding-right: 16px;
    }

    .mail-row {
        display: grid;
        gap: 6px;
    }

    .headers {
        grid-template-columns: 1fr;
        gap: 2px 0;
    }

    .headers dt {
        margin-top: 8px;
    }

    .headers dt:first-child {
        margin-top: 0;
    }
}