:root {
    --it-bg: #0f172a;
    --it-card: #1e293b;
    --it-card-hi: #2a3a52;
    --it-border: #334155;
    --it-text: #e2e8f0;
    --it-text-mute: #94a3b8;
    --it-accent: #818cf8;
    --it-accent-solid: #6366f1;
    --it-accent-bg: rgba(99,102,241,0.15);
    --it-success: #34d399;
    --it-danger: #ef4444;
}
* { margin: 0; padding: 0; box-sizing: border-box; }
body {
    font-family: -apple-system, BlinkMacSystemFont, 'Segoe UI', 'PingFang SC', sans-serif;
    background: var(--it-bg); color: var(--it-text); min-height: 100vh;
}
.it-fullscreen { min-height: 100vh; display: flex; flex-direction: column; }
.it-header {
    background: rgba(15,23,42,0.85); backdrop-filter: blur(8px);
    border-bottom: 1px solid var(--it-border); height: 56px;
    padding: 0 16px; display: flex; align-items: center; gap: 12px;
    position: sticky; top: 0; z-index: 100;
}
.it-back { color: var(--it-text-mute); text-decoration: none; display: inline-flex; align-items: center; gap: 6px; font-size: 14px; }
.it-back:hover { color: var(--it-text); }
.it-title { font-size: 16px; font-weight: 600; }
.it-spacer { flex: 1; }

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

.it-tabs {
    display: flex; gap: 4px; background: var(--it-bg);
    border: 1px solid var(--it-border); border-radius: 10px;
    padding: 4px; margin-bottom: 20px;
}
.it-tab {
    flex: 1; background: transparent; color: var(--it-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;
}
.it-tab:hover { color: var(--it-text); }
.it-tab.active { background: var(--it-accent-bg); color: var(--it-accent); font-weight: 500; }

.it-pane.hidden { display: none; }
.hidden { display: none !important; }

/* Drop zone */
.it-drop {
    border: 2px dashed var(--it-border); border-radius: 12px;
    padding: 40px 20px; text-align: center; cursor: pointer;
    transition: border-color .15s, background .15s;
}
.it-drop:hover, .it-drop.dragover {
    border-color: var(--it-accent); background: var(--it-accent-bg);
}
.it-drop-icon { font-size: 44px; color: var(--it-text-mute); margin-bottom: 8px; display: block; }
.it-drop-title { font-size: 15px; color: var(--it-text); margin-bottom: 4px; }
.it-drop-hint { font-size: 12px; color: var(--it-text-mute); }

.it-cmp-controls {
    margin-top: 18px; padding: 16px;
    background: var(--it-card-hi); border: 1px solid var(--it-border);
    border-radius: 10px;
}
.it-row { margin-bottom: 14px; }
.it-row:last-child { margin-bottom: 0; }
.it-label {
    display: flex; justify-content: space-between; align-items: center;
    font-size: 13px; color: var(--it-text-mute); margin-bottom: 6px;
}
.it-val { color: var(--it-accent); font-weight: 500; }

.it-range {
    width: 100%; -webkit-appearance: none; appearance: none;
    height: 4px; background: var(--it-border); border-radius: 4px;
    outline: none;
}
.it-range::-webkit-slider-thumb {
    -webkit-appearance: none; appearance: none;
    width: 16px; height: 16px; border-radius: 50%;
    background: var(--it-accent-solid); cursor: pointer;
}
.it-range::-moz-range-thumb {
    width: 16px; height: 16px; border-radius: 50%;
    background: var(--it-accent-solid); cursor: pointer; border: none;
}

.it-segment {
    display: inline-flex; gap: 4px;
    background: var(--it-bg); border: 1px solid var(--it-border);
    border-radius: 8px; padding: 3px;
}
.it-seg {
    background: transparent; color: var(--it-text-mute);
    border: none; padding: 7px 14px; border-radius: 5px;
    cursor: pointer; font-size: 13px; font-family: inherit;
}
.it-seg:hover { color: var(--it-text); }
.it-seg.active { background: var(--it-accent-bg); color: var(--it-accent); font-weight: 500; }

/* Preview */
.it-preview { margin-top: 18px; }
.it-preview-pair {
    display: grid; grid-template-columns: 1fr 1fr; gap: 14px;
}
.it-preview-side {
    background: var(--it-card-hi); border: 1px solid var(--it-border);
    border-radius: 10px; padding: 12px;
}
.it-preview-label {
    font-size: 12px; color: var(--it-text-mute); margin-bottom: 8px;
    display: flex; justify-content: space-between; align-items: center; gap: 6px;
}
.it-preview-side img {
    max-width: 100%; max-height: 320px; display: block; margin: 0 auto;
    border-radius: 6px;
    background-color: #0a0e1a;
    background-image:
        linear-gradient(45deg, #1a2030 25%, transparent 25%),
        linear-gradient(-45deg, #1a2030 25%, transparent 25%),
        linear-gradient(45deg, transparent 75%, #1a2030 75%),
        linear-gradient(-45deg, transparent 75%, #1a2030 75%);
    background-size: 20px 20px;
    background-position: 0 0, 0 10px, 10px -10px, -10px 0;
}
.it-savings { color: var(--it-success); font-weight: 500; }

.it-actions {
    margin-top: 14px; display: flex; gap: 8px; flex-wrap: wrap;
}
.it-btn {
    background: transparent; color: var(--it-text);
    border: 1px solid var(--it-border); padding: 9px 16px;
    border-radius: 8px; cursor: pointer; font-size: 13px; font-family: inherit;
    display: inline-flex; align-items: center; gap: 6px;
}
.it-btn:hover { background: var(--it-card-hi); border-color: var(--it-accent-solid); }
.it-btn-primary { background: var(--it-accent-solid); color: #fff; border-color: var(--it-accent-solid); }
.it-btn-primary:hover { background: var(--it-accent); }

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

@media (max-width: 720px) {
    .it-card { padding: 16px; }
    .it-preview-pair { grid-template-columns: 1fr; }
    .it-tab { font-size: 13px; padding: 8px 4px; }
}