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

:root {
    --bg:       #000000;
    --fg:       #ffffff;
    --border:   rgba(255, 255, 255, 0.12);
    --muted:    rgba(255, 255, 255, 0.45);
    --header-h: 60px;
}

html, body {
    height: 100%;
    width: 100%;
    background: var(--bg);
    color: var(--fg);
    font-family: 'Courier New', Courier, monospace;
    overflow: hidden;
}

.hidden {
    display: none !important;
}

/* ─────────────────────────────────────────
   Login Screen
───────────────────────────────────────── */
#login-screen {
    display: flex;
    align-items: center;
    justify-content: center;
    height: 100vh;
    background: var(--bg);
}

.login-container {
    position: relative; /* anchor for .lang-toggle */
    display: flex;
    flex-direction: column;
    align-items: center;
    gap: 28px;
    padding: 52px 60px 40px;
    border: 1px solid var(--border);
}

.login-logo {
    max-width: 200px;
    max-height: 80px;
    object-fit: contain;
    filter: brightness(0) invert(1); /* force white on black */
}

.login-title {
    font-size: 1rem;
    font-weight: 400;
    letter-spacing: 0.12em;
    text-transform: uppercase;
    color: var(--fg);
    text-align: center;
}

.login-btn {
    padding: 10px 30px;
    background: var(--fg);
    color: var(--bg);
    border: none;
    font-family: 'Courier New', Courier, monospace;
    font-size: 0.9rem;
    font-weight: 700;
    letter-spacing: 0.08em;
    cursor: pointer;
    transition: opacity 0.15s ease;
}

.login-btn:hover:not(:disabled) {
    opacity: 0.82;
}

.login-btn:disabled {
    opacity: 0.35;
    cursor: not-allowed;
}

.login-footer {
    font-size: 0.72rem;
    color: var(--muted);
    text-align: center;
    letter-spacing: 0.05em;
}

/* Language toggle — bottom-right of login box */
.lang-toggle {
    position: absolute;
    bottom: 10px;
    right: 12px;
    background: none;
    border: 1px solid var(--border);
    color: var(--muted);
    font-family: 'Courier New', Courier, monospace;
    font-size: 0.68rem;
    letter-spacing: 0.08em;
    padding: 2px 7px;
    cursor: pointer;
    transition: color 0.15s, border-color 0.15s;
}

.lang-toggle:hover {
    color: var(--fg);
    border-color: rgba(255,255,255,0.4);
}

/* Error message inside login box */
.login-error {
    font-size: 0.75rem;
    color: var(--fg);
    background: rgba(255,255,255,0.08);
    border: 1px solid rgba(255,255,255,0.2);
    padding: 6px 14px;
    text-align: center;
    max-width: 280px;
    letter-spacing: 0.03em;
}

/* ─────────────────────────────────────────
   Terminal Screen
───────────────────────────────────────── */
#terminal-screen {
    display: flex;
    flex-direction: column;
    height: 100vh;
}

/* Header: 30px exactly */
#app-header {
    display: flex;
    align-items: center;
    justify-content: space-between;
    height: var(--header-h);
    min-height: var(--header-h);
    padding: 0 10px;
    border-bottom: 1px solid var(--border);
    background: var(--bg);
    flex-shrink: 0;
}

.header-left {
    display: flex;
    align-items: center;
    gap: 10px;
}

.header-logo {
    height: 36px;
    object-fit: contain;
    filter: brightness(0) invert(1);
}

.header-hostname {
    font-size: 0.85rem;
    color: var(--muted);
    letter-spacing: 0.06em;
}

.header-right {
    font-size: 0.85rem;
    color: rgba(255, 255, 255, 0.65);
    letter-spacing: 0.05em;
}

/* Terminal takes all remaining height */
#terminal-container {
    flex: 1 1 0;
    overflow: hidden;
    min-height: 0; /* critical for flex children */
    display: flex;
    justify-content: center;
    align-items: flex-start;
    padding: 4px 0 0 0;
}

/* Let xterm size itself to cols×rows — do not stretch it */
.xterm {
    display: inline-block;
}

.xterm-viewport {
    background-color: #000000 !important;
}

.xterm-screen {
    background-color: #000000 !important;
}

/* ─────────────────────────────────────────
   Overlays (reconnect / offline)
───────────────────────────────────────── */
.overlay {
    position: fixed;
    inset: 0;
    background: rgba(0, 0, 0, 0.90);
    display: flex;
    align-items: center;
    justify-content: center;
    z-index: 9999;
}

.overlay-content {
    display: flex;
    flex-direction: column;
    align-items: center;
    gap: 14px;
    text-align: center;
}

.overlay-icon {
    font-size: 2.4rem;
    line-height: 1;
    color: var(--fg);
}

.overlay-content p {
    font-size: 1rem;
    letter-spacing: 0.06em;
    color: var(--fg);
}

.overlay-sub {
    font-size: 0.82rem !important;
    color: var(--muted) !important;
}