:root {
    --bg: #070f1c;
    --bg-2: #0c1c2d;
    --panel: rgba(255, 255, 255, 0.05);
    --panel-strong: rgba(255, 255, 255, 0.08);
    --border: rgba(255, 255, 255, 0.16);
    --muted: #9db4d2;
    --text: #e7edf5;
    --accent: #5cf2e8;
    --accent-2: #ffb86b;
    --danger: #ff6b6b;
    --shadow: 0 20px 60px rgba(0, 0, 0, 0.35);
}

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

body {
    margin: 0;
    min-height: 100vh;
    background: radial-gradient(circle at 20% 20%, #0f2a3f 0, rgba(10, 20, 35, 0.6) 35%, #060b14 65%, #050910 100%),
        linear-gradient(135deg, #0b1828, #0f1f33 60%, #0a1422);
    color: var(--text);
    font-family: 'DM Sans', 'Space Grotesk', sans-serif;
    letter-spacing: 0.01em;
    overflow-x: hidden;
    overflow-y: auto;
}

.bg-aurora,
.bg-grid {
    position: fixed;
    inset: 0;
    pointer-events: none;
    z-index: 0;
}

.bg-aurora {
    background: radial-gradient(40% 35% at 20% 30%, rgba(92, 242, 232, 0.25), transparent),
        radial-gradient(30% 30% at 80% 20%, rgba(255, 184, 107, 0.18), transparent),
        radial-gradient(50% 40% at 50% 80%, rgba(84, 132, 255, 0.14), transparent);
    filter: blur(40px);
    opacity: 0.9;
}

.bg-grid {
    background-image:
        linear-gradient(rgba(255, 255, 255, 0.03) 1px, transparent 1px),
        linear-gradient(90deg, rgba(255, 255, 255, 0.03) 1px, transparent 1px);
    background-size: 60px 60px;
    mask-image: radial-gradient(circle at 50% 40%, rgba(255, 255, 255, 0.8), transparent 70%);
    opacity: 0.4;
}

.app-shell {
    position: relative;
    z-index: 1;
    max-width: 1200px;
    margin: 0 auto;
    padding: 32px 20px 56px;
}

.app-copyright {
    text-align: right;
    color: var(--muted);
    font-size: 12px;
    letter-spacing: 0.08em;
    text-transform: uppercase;
    opacity: 0.8;
}

.hero {
    display: flex;
    flex-direction: column;
    gap: 18px;
    align-items: stretch;
    margin-bottom: 16px;
}

.hero-copy h1 {
    margin: 8px 0;
    font-size: clamp(32px, 6vw, 48px);
    letter-spacing: -0.02em;
}

.hero-copy .lede {
    margin: 8px 0 12px;
    max-width: 760px;
    color: var(--muted);
    line-height: 1.6;
}

.eyebrow {
    letter-spacing: 0.2em;
    text-transform: uppercase;
    font-size: 12px;
    color: var(--muted);
}

.pill-row {
    display: flex;
    flex-wrap: wrap;
    gap: 10px;
    margin-top: 8px;
}

.pill {
    padding: 8px 12px;
    border-radius: 999px;
    background: var(--panel);
    border: 1px solid var(--border);
    color: var(--muted);
    font-size: 12px;
    backdrop-filter: blur(8px);
}

.hero-actions .floating-card {
    width: 100%;
    max-width: 320px;
}

.floating-card {
    background: var(--panel);
    border: 1px solid var(--border);
    border-radius: 16px;
    padding: 14px 16px;
    box-shadow: var(--shadow);
    backdrop-filter: blur(12px);
}

.floating-card label {
    display: block;
    margin-bottom: 6px;
    font-size: 13px;
    color: var(--muted);
}

.floating-card select,
.floating-card input {
    width: 100%;
    margin-bottom: 8px;
}

.layout {
    display: grid;
    grid-template-columns: 1fr;
    gap: 16px;
    align-items: stretch;
}

.control-stack {
    display: flex;
    flex-direction: column;
    gap: 14px;
}

.controls-container {
    background: var(--panel);
    border: 1px solid var(--border);
    border-radius: 18px;
    padding: 12px;
    display: grid;
    grid-template-columns: repeat(auto-fit, minmax(260px, 1fr));
    gap: 10px;
    box-shadow: var(--shadow);
    backdrop-filter: blur(10px);
}

.control-group {
    background: var(--panel-strong);
    border: 1px solid var(--border);
    border-radius: 14px;
    padding: 10px;
    display: flex;
    flex-direction: column;
    gap: 8px;
}

.control-heading {
    display: flex;
    align-items: center;
    gap: 10px;
    margin-bottom: 10px;
}

.control-heading h3 {
    margin: 0;
    letter-spacing: -0.01em;
}

.dot {
    width: 12px;
    height: 12px;
    border-radius: 50%;
    background: var(--accent);
    box-shadow: 0 0 0 8px rgba(92, 242, 232, 0.08);
}

.control-row {
    display: grid;
    grid-template-columns: repeat(auto-fit, minmax(130px, 1fr));
    gap: 8px;
    align-items: stretch;
}

.control-row.compact {
    grid-template-columns: repeat(auto-fit, minmax(110px, 1fr));
}

.control-row > * {
    width: 100%;
}

.chip-row {
    display: flex;
    flex-wrap: wrap;
    gap: 8px;
    align-items: center;
}

input,
select,
button {
    font-family: 'DM Sans', 'Space Grotesk', sans-serif;
    border-radius: 12px;
    border: 1px solid var(--border);
}

input,
select {
    background: rgba(255, 255, 255, 0.06);
    color: var(--text);
    padding: 9px 12px;
    min-width: 130px;
    outline: none;
    transition: border-color 0.2s ease, box-shadow 0.2s ease;
}

input:focus,
select:focus {
    border-color: var(--accent);
    box-shadow: 0 0 0 6px rgba(92, 242, 232, 0.08);
}

input::placeholder {
    color: rgba(255, 255, 255, 0.5);
}

button {
    background: linear-gradient(120deg, #5cf2e8, #2dd4bf);
    color: #04121d;
    font-weight: 700;
    border: none;
    padding: 9px 12px;
    cursor: pointer;
    transition: transform 0.15s ease, box-shadow 0.15s ease, filter 0.15s ease;
    box-shadow: 0 12px 30px rgba(45, 212, 191, 0.25);
}

button:hover {
    transform: translateY(-1px);
    filter: brightness(1.02);
}

button:disabled {
    opacity: 0.6;
    cursor: not-allowed;
    transform: none;
    box-shadow: none;
}

button.ghost,
.chip.ghost {
    background: rgba(255, 255, 255, 0.04);
    color: var(--text);
    border: 1px solid var(--border);
    box-shadow: none;
}

button.danger {
    background: linear-gradient(120deg, #ff6b6b, #ff8f70);
    color: #1a0b0b;
    box-shadow: 0 12px 30px rgba(255, 139, 112, 0.28);
}

.chip {
    padding: 8px 12px;
    font-size: 13px;
    background: rgba(92, 242, 232, 0.12);
    color: var(--text);
    border: 1px solid rgba(92, 242, 232, 0.28);
    box-shadow: none;
}

.chip:hover {
    filter: brightness(1.05);
    transform: translateY(-1px);
}

.info-row {
    display: grid;
    grid-template-columns: 1.2fr 1fr;
    gap: 10px;
}

.message-area {
    border-radius: 14px;
    color: var(--muted);
    line-height: 1.5;
}

.properties-area {
    display: grid;
    grid-template-columns: repeat(auto-fit, minmax(90px, 1fr));
    gap: 8px;
    align-items: stretch;
}

.property {
    background: rgba(255, 255, 255, 0.05);
    border: 1px solid var(--border);
    border-radius: 12px;
    padding: 10px;
    text-align: center;
}

.property p {
    margin: 0;
    color: var(--muted);
    font-size: 13px;
}

.property span {
    display: block;
    margin-top: 6px;
    font-size: 20px;
    font-weight: 700;
    letter-spacing: 0.01em;
}

.step-controls {
    display: flex;
    gap: 8px;
    flex-wrap: wrap;
    align-items: center;
}

.visual-panel {
    padding: 14px;
    background: var(--panel);
    border: 1px solid var(--border);
    border-radius: 18px;
    box-shadow: var(--shadow);
    backdrop-filter: blur(12px);
}

.visual-header {
    display: flex;
    align-items: center;
    justify-content: space-between;
    gap: 12px;
    flex-wrap: wrap;
    margin-bottom: 12px;
}

.legend {
    display: flex;
    gap: 14px;
    align-items: center;
    color: var(--muted);
    font-size: 13px;
}

.legend-dot {
    width: 10px;
    height: 10px;
    border-radius: 50%;
    display: inline-block;
    margin-right: 6px;
}

.legend-dot.primary { background: #60a5fa; }
.legend-dot.success { background: #2dd4bf; }
.legend-dot.warn { background: #ffb86b; }

.view-controls {
    display: flex;
    flex-wrap: wrap;
    align-items: center;
    gap: 10px;
}

.view-controls #zoom-control {
    display: flex;
    align-items: center;
    gap: 8px;
    background: rgba(255, 255, 255, 0.04);
    border: 1px solid var(--border);
    padding: 8px 10px;
    border-radius: 12px;
}

.view-controls label {
    color: var(--muted);
    font-size: 13px;
}

#zoomSlider {
    width: 120px;
}

.canvas-container {
    position: relative;
    border-radius: 16px;
    border: 1px solid var(--border);
    background: radial-gradient(circle at 10% 20%, rgba(92, 242, 232, 0.1), rgba(10, 20, 35, 0.6)),
        radial-gradient(circle at 80% 10%, rgba(255, 184, 107, 0.12), rgba(10, 20, 35, 0.8)),
        rgba(8, 16, 28, 0.9);
    padding: 12px;
    box-shadow: inset 0 1px 0 rgba(255, 255, 255, 0.05);
    min-height: 520px;
    overflow: hidden;
}

#bstCanvas {
    display: block;
    width: 100%;
    height: 100%;
    border-radius: 12px;
}

#canvas-copyright {
    position: absolute;
    top: 12px;
    left: 16px;
    font-size: 12px;
    color: var(--muted);
    background: rgba(0, 0, 0, 0.3);
    padding: 4px 6px;
    border-radius: 8px;
}

@media (min-width: 1200px) {
    .hero {
        flex-direction: row;
        flex-wrap: wrap;
        align-items: flex-start;
        justify-content: space-between;
    }

    .hero-actions .floating-card {
        width: 280px;
    }

    .layout {
        grid-template-columns: minmax(320px, 1fr) 1.05fr;
        align-items: start;
    }
}

@media (max-width: 1024px) {
    .info-row {
        grid-template-columns: 1fr;
    }
}

@media (max-width: 640px) {
    .canvas-container {
        padding: 8px;
    }

    .view-controls {
        width: 100%;
    }

    .pill-row {
        gap: 6px;
    }
}