:root {
    --dt-bg: #0f172a;
    --dt-card: #1e293b;
    --dt-card-hi: #2a3a52;
    --dt-border: #334155;
    --dt-text: #e2e8f0;
    --dt-text-mute: #94a3b8;
    --dt-accent: #818cf8;
    --dt-accent-solid: #6366f1;
    --dt-accent-bg: rgba(99,102,241,0.15);
    --dt-success: #34d399;
    --dt-danger: #ef4444;
    --dt-warning: #fbbf24;
}

* { margin: 0; padding: 0; box-sizing: border-box; }
body {
    font-family: -apple-system, BlinkMacSystemFont, 'Segoe UI', 'PingFang SC', sans-serif;
    background: var(--dt-bg); color: var(--dt-text); min-height: 100vh;
}
.dt-fullscreen { min-height: 100vh; display: flex; flex-direction: column; }

.dt-header {
    background: rgba(15,23,42,0.85); backdrop-filter: blur(8px);
    border-bottom: 1px solid var(--dt-border); height: 56px;
    padding: 0 16px; display: flex; align-items: center; gap: 12px;
    position: sticky; top: 0; z-index: 100;
}
.dt-back { color: var(--dt-text-mute); text-decoration: none; display: inline-flex; align-items: center; gap: 6px; font-size: 14px; }
.dt-back:hover { color: var(--dt-text); }
.dt-title { font-size: 16px; font-weight: 600; }
.dt-spacer { flex: 1; }

.dt-main {
    flex: 1; padding: 24px 16px 60px;
    max-width: 980px; width: 100%; margin: 0 auto;
}
.dt-card {
    background: var(--dt-card); border: 1px solid var(--dt-border);
    border-radius: 16px; padding: 22px;
}

.dt-tabs {
    display: flex; gap: 4px;
    background: var(--dt-bg); border: 1px solid var(--dt-border);
    border-radius: 10px; padding: 4px; margin-bottom: 20px;
}
.dt-tab {
    flex: 1; background: transparent; color: var(--dt-text-mute);
    border: none; padding: 9px 8px; border-radius: 7px; cursor: pointer;
    font-size: 14px; font-family: inherit;
    display: inline-flex; align-items: center; justify-content: center; gap: 6px;
    transition: all .15s;
}
.dt-tab:hover { color: var(--dt-text); }
.dt-tab.active { background: var(--dt-accent-bg); color: var(--dt-accent); font-weight: 500; }

.dt-pane.hidden { display: none; }

.dt-actions {
    display: flex; flex-wrap: wrap; gap: 8px; align-items: center;
    margin-bottom: 12px;
}
.dt-btn {
    background: transparent; color: var(--dt-text);
    border: 1px solid var(--dt-border);
    padding: 8px 14px; border-radius: 8px; cursor: pointer;
    font-size: 13px; font-family: inherit;
    display: inline-flex; align-items: center; gap: 6px;
    transition: all .15s;
}
.dt-btn:hover { background: var(--dt-card-hi); border-color: var(--dt-accent-solid); }
.dt-btn-primary { background: var(--dt-accent-solid); color: #fff; border-color: var(--dt-accent-solid); }
.dt-btn-primary:hover { background: var(--dt-accent); }
.dt-btn-mini { padding: 5px 10px; font-size: 12px; }
.dt-btn-copy { margin-top: 8px; }

.dt-checkbox {
    display: inline-flex; align-items: center; gap: 8px;
    cursor: pointer; font-size: 13px; color: var(--dt-text-mute);
    user-select: none;
}
.dt-checkbox-box { display: inline-flex; align-items: center; flex-shrink: 0; }
.dt-checkbox-box input { margin: 0; width: 16px; height: 16px; cursor: pointer; }
.dt-checkbox-text { white-space: nowrap; }
.dt-checkbox:hover { color: var(--dt-text); }

.dt-status {
    margin-left: auto; font-size: 12px;
    color: var(--dt-text-mute);
}
.dt-status.error { color: var(--dt-danger); }
.dt-status.success { color: var(--dt-success); }

.dt-input {
    width: 100%; padding: 12px;
    border-radius: 8px;
    background: var(--dt-bg); border: 1px solid var(--dt-border);
    color: var(--dt-text); font-size: 13px;
    font-family: 'Menlo', 'Consolas', monospace;
    line-height: 1.6; resize: vertical; outline: none;
    transition: border-color .15s, box-shadow .15s;
}
.dt-input:focus {
    border-color: var(--dt-accent-solid);
    box-shadow: 0 0 0 3px var(--dt-accent-bg);
}
.dt-input.dt-output { background: rgba(0,0,0,0.2); margin-top: 10px; }
.dt-input-row { flex: 1; }

/* 时间戳 */
.dt-now {
    display: flex; flex-wrap: wrap; align-items: center; gap: 8px;
    background: var(--dt-card-hi); border: 1px solid var(--dt-border);
    border-radius: 10px; padding: 12px 16px; margin-bottom: 18px;
}
.dt-now-label { color: var(--dt-text-mute); font-size: 13px; }
.dt-now-val {
    font-size: 18px; font-weight: 600; color: var(--dt-accent);
    font-family: 'Menlo', 'Consolas', monospace;
    font-variant-numeric: tabular-nums;
}
.dt-now-unit { color: var(--dt-text-mute); font-size: 12px; margin-right: 6px; }

.dt-row { margin-bottom: 18px; }
.dt-row-inline { display: flex; gap: 8px; align-items: stretch; }
.dt-row-inline .dt-input-row { padding: 11px 14px; font-size: 14px; }
.dt-row-inline .dt-btn { flex: 0 0 auto; }
.dt-label {
    display: block; font-size: 13px; color: var(--dt-text-mute);
    margin-bottom: 6px;
}
.dt-result {
    margin-top: 10px; padding: 14px 16px;
    background: var(--dt-card-hi); border: 1px solid var(--dt-border);
    border-radius: 8px;
    font-size: 14px; color: var(--dt-text);
    line-height: 1.7; min-height: 50px;
    word-break: break-all;
}
.dt-result-empty { color: var(--dt-text-mute); }
.dt-result-row { display: flex; justify-content: space-between; gap: 12px; align-items: baseline; }
.dt-result-row b { color: var(--dt-accent); font-family: 'Menlo', 'Consolas', monospace; font-weight: 600; }
.dt-result-row span { color: var(--dt-text-mute); font-size: 12px; flex-shrink: 0; }

.dt-foot { margin-top: 16px; color: var(--dt-text-mute); font-size: 12px; }

.dt-seo {
    margin-top: 32px; padding: 20px 24px;
    background: var(--dt-card); border: 1px solid var(--dt-border);
    border-radius: 12px;
    color: var(--dt-text-mute); font-size: 14px; line-height: 1.7;
}
.dt-seo h2 { color: var(--dt-text); font-size: 16px; margin-bottom: 10px; }
.dt-seo p { margin-bottom: 8px; }
.dt-seo b { color: var(--dt-text); font-weight: 500; }

@media (max-width: 540px) {
    .dt-card { padding: 16px; }
    .dt-tab { font-size: 12px; padding: 8px 4px; }
    .dt-row-inline { flex-direction: column; }
    .dt-now-val { font-size: 14px; }
}