:root {
    --bg: #54545a;
    --tab: #00675b;
    --tab-hover: #0e8f80;
    --tab-active: #0aa48f;
    --bar: #2d2d30;
    --shadow: rgba(0, 0, 0, 0.45);
    --text: #ffffff;
}

* {
    box-sizing: border-box;
}

html, body {
    height: 100%;
}

body {
    margin: 0;
    background: var(--bg);
    color: var(--text);
    font-family: system-ui, -apple-system, Segoe UI, Roboto, Helvetica, Arial, "Apple Color Emoji", "Segoe UI Emoji", "Segoe UI Symbol";
}

/* Layout */
#app {
    position: fixed;
    inset: 0;
    display: grid;
    grid-template-rows: 1fr auto;
    background: var(--bg);
}

#viewer {
    width: 100%;
    height: 100%;
    border: none;
    background: transparent;
}

/* Bottom bar */
#tabbar {
    position: relative;
    width: 100%;
    background: var(--bar);
    border-top: 1px solid rgba(255,255,255,0.08);
    box-shadow: 0 -6px 18px var(--shadow);
}

#tabs {
    display: grid;
    grid-auto-flow: column;
    grid-auto-columns: 1fr;
    gap: 12px;
    padding: 10px 12px;
    align-items: center;
}

/* Tabs */
.tab {
    appearance: none;
    border: none;
    background: var(--tab);
    color: var(--text);
    font-weight: 700;
    letter-spacing: 0.02em;
    border-radius: 12px;
    padding: 16px 12px;
    width: 100%;
    text-transform: uppercase;
    cursor: pointer;
    outline: none;
    box-shadow: 0 2px 0 rgba(0,0,0,0.35), inset 0 -2px 0 rgba(0,0,0,0.15);
    transition: transform 120ms ease, background 120ms ease, box-shadow 120ms ease;
    white-space: nowrap;
    overflow: hidden;
    text-overflow: ellipsis;
}

.tab:hover {
    background: var(--tab-hover);
}

.tab:active {
    transform: translateY(1px);
}

.tab[aria-selected="true"] {
    background: var(--tab-active);
    box-shadow: 0 0 0 2px rgba(255,255,255,0.12) inset, 0 2px 0 rgba(0,0,0,0.35);
}

/* Small screens */
@media (max-width: 680px) {
    .tab {
        padding: 14px 8px;
        font-size: 0.95rem;
    }
}