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

body {
    font-family: 'Segoe UI', system-ui, -apple-system, sans-serif;
    background: #0a0e1a;
    color: #e0e0e0;
    min-height: 100vh;
    display: flex;
    flex-direction: column;
}

/* ---------- header ---------- */

header {
    padding: 1.2rem 1.5rem;
    background: linear-gradient(135deg, #0d1b2a, #1b2838);
    border-bottom: 1px solid #1e90ff33;
}

.header-row {
    display: flex;
    align-items: center;
    justify-content: space-between;
    gap: 1rem;
    flex-wrap: wrap;
}

header h1 {
    font-size: 1.5rem;
}

header p {
    color: #8899aa;
    font-size: 0.85rem;
    margin-top: 0.4rem;
}

.header-tools {
    display: flex;
    align-items: center;
    gap: 1rem;
}

.sync-status {
    font-size: 0.8rem;
    color: #8899aa;
    background: #141c2e;
    border: 1px solid #1e3050;
    border-radius: 6px;
    padding: 0.35rem 0.8rem;
    max-width: 420px;
    overflow: hidden;
    text-overflow: ellipsis;
    white-space: nowrap;
}

.btn-upload {
    display: inline-block;
    background: linear-gradient(135deg, #1e90ff33, #1e90ff18);
    border: 1px solid #1e90ff66;
    color: #cfe8ff;
    font-size: 0.9rem;
    padding: 0.5rem 1.1rem;
    border-radius: 8px;
    cursor: pointer;
    transition: all 0.2s;
    user-select: none;
}

.btn-upload:hover {
    background: linear-gradient(135deg, #1e90ff55, #1e90ff28);
    transform: translateY(-1px);
}

/* ---------- layout ---------- */

.layout {
    display: grid;
    grid-template-columns: 340px 1fr;
    flex: 1;
    min-height: 0;
}

.sidebar {
    background: #0d1322;
    border-right: 1px solid #1e2a3a;
    overflow-y: auto;
    max-height: calc(100vh - 220px);
}

.model-tree {
    padding: 0.8rem;
    display: flex;
    flex-direction: column;
    gap: 0.4rem;
}

.tree-loading {
    color: #556677;
    font-size: 0.9rem;
    padding: 1rem;
    text-align: center;
}

/* ---------- model node ---------- */

.model-node {
    border: 1px solid #1e2a3a;
    border-radius: 10px;
    overflow: hidden;
}

.model-head {
    display: flex;
    align-items: center;
    gap: 0.6rem;
    padding: 0.7rem 0.8rem;
    cursor: pointer;
    background: #141c2e;
    transition: background 0.15s;
    user-select: none;
}

.model-head:hover {
    background: #1a2540;
}

.chev {
    font-size: 0.7rem;
    color: #556677;
    transition: transform 0.2s;
    width: 12px;
}

.model-node.open .chev {
    transform: rotate(90deg);
}

.model-icon {
    font-size: 1.1rem;
}

.model-name {
    font-weight: 600;
    font-size: 0.95rem;
    flex: 1;
    overflow: hidden;
    text-overflow: ellipsis;
    white-space: nowrap;
}

.model-count {
    font-size: 0.75rem;
    color: #8899aa;
    background: #1e2a3a;
    border-radius: 10px;
    padding: 0.1rem 0.55rem;
}

.version-list {
    display: none;
}

.model-node.open .version-list {
    display: block;
}

/* ---------- version item ---------- */

.version-item {
    display: flex;
    align-items: flex-start;
    gap: 0.6rem;
    padding: 0.55rem 0.8rem 0.55rem 1.6rem;
    cursor: pointer;
    border-top: 1px solid #1e2a3a66;
    transition: background 0.15s;
}

.version-item:hover {
    background: #1a2540;
}

.version-item.active {
    background: #1e90ff1e;
    box-shadow: inset 3px 0 0 #1e90ff;
}

.version-dot {
    width: 8px;
    height: 8px;
    border-radius: 50%;
    background: #334455;
    margin-top: 5px;
    flex-shrink: 0;
}

.version-item.active .version-dot {
    background: #1e90ff;
    box-shadow: 0 0 8px #1e90ff;
}

.version-info {
    min-width: 0;
}

.version-date {
    font-size: 0.85rem;
    color: #cfe8ff;
}

.latest-badge {
    font-style: normal;
    font-size: 0.65rem;
    color: #00ff88;
    border: 1px solid #00ff8855;
    border-radius: 4px;
    padding: 0.05rem 0.4rem;
    margin-left: 0.3rem;
    vertical-align: 1px;
}

.version-sub {
    font-size: 0.72rem;
    color: #556677;
    margin-top: 0.15rem;
    overflow: hidden;
    text-overflow: ellipsis;
    white-space: nowrap;
}

/* ---------- viewer ---------- */

.viewer-main {
    min-height: 0;
    position: relative;
}

.viewer-panel {
    position: relative;
    width: 100%;
    height: calc(100vh - 220px);
    min-height: 420px;
}

#viewer {
    width: 100%;
    height: 100%;
    display: block;
}

.viewer-empty {
    position: absolute;
    inset: 0;
    display: flex;
    flex-direction: column;
    align-items: center;
    justify-content: center;
    gap: 0.8rem;
    color: #445566;
    pointer-events: none;
    text-align: center;
}

.viewer-empty-icon {
    font-size: 3.5rem;
    opacity: 0.5;
}

.viewer-empty p {
    font-size: 1rem;
    line-height: 1.6;
}

.viewer-info {
    position: absolute;
    left: 1rem;
    bottom: 1rem;
    display: flex;
    gap: 1rem;
    align-items: center;
    background: #0d1322cc;
    border: 1px solid #1e2a3a;
    border-radius: 8px;
    padding: 0.5rem 1rem;
    font-size: 0.8rem;
    backdrop-filter: blur(6px);
}

#info-name {
    font-weight: 700;
    color: #cfe8ff;
}

#info-date {
    color: #8899aa;
}

#info-size {
    color: #556677;
}

/* ---------- toast ---------- */

.toast {
    position: fixed;
    right: 1.2rem;
    bottom: 1.2rem;
    background: #141c2e;
    border: 1px solid #00ff8855;
    color: #cfe8ff;
    border-radius: 10px;
    padding: 0.8rem 1.2rem;
    font-size: 0.88rem;
    opacity: 0;
    transform: translateY(12px);
    transition: all 0.3s;
    pointer-events: none;
    z-index: 50;
    max-width: 420px;
}

.toast.show {
    opacity: 1;
    transform: translateY(0);
}

.toast.error {
    border-color: #ff556688;
}

/* ---------- footer ---------- */

footer {
    text-align: center;
    padding: 0.7rem;
    color: #556677;
    font-size: 0.78rem;
    border-top: 1px solid #1e2a3a;
}

/* ---------- responsive ---------- */

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

    .sidebar {
        max-height: 300px;
        border-right: none;
        border-bottom: 1px solid #1e2a3a;
    }

    .viewer-panel {
        height: 60vh;
    }
}