@import url('https://fonts.googleapis.com/css2?family=Inter:wght@400;600;700&display=swap');

:root {
    --bg-color: #0f111a;
    --text-color: #e0e0e0;
    --node-bg: #1a1c23;
    --node-text: #4fc3f7;
    --border-color: rgba(255, 255, 255, 0.1);
    --input-bg: #12141d;
    --accent: #2196f3;
    --leaf-color: #81c784;
}

body.light-theme {
    --bg-color: #f5f5f7;
    --text-color: #1d1d1f;
    --node-bg: #ffffff;
    --node-text: #2196f3;
    --border-color: rgba(0, 0, 0, 0.1);
    --input-bg: #f5f5f7;
    --accent: #007aff;
    --leaf-color: #34c759;
}

body {
    margin: 0;
    padding: 20px;
    background: var(--bg-color);
    font-family: 'Inter', sans-serif;
    color: var(--text-color);
    overflow: hidden;
    display: flex;
    flex-direction: column;
    align-items: center;
}

.merkle-wrap {
    position: relative;
    height: 400px;
    width: 100%;
    max-width: 900px;
}

.merkle-node {
    position: absolute;
    transform: translate(-50%, -50%);
    padding: 14px 10px;
    background: var(--node-bg);
    color: var(--node-text);
    border-radius: 12px;
    min-width: 110px;
    text-align: center;
    font-weight: 700;
    font-family: 'JetBrains Mono', monospace;
    font-size: 0.85rem;
    border: 1px solid var(--border-color);
    box-shadow: 0 10px 20px rgba(0, 0, 0, 0.2);
    transition: all 0.4s cubic-bezier(0.175, 0.885, 0.32, 1.275);
    z-index: 2;
}

.merkle-node.root {
    border-color: var(--accent);
    color: var(--accent);
}

.merkle-node.changed {
    background: #ef5350 !important;
    color: #fff !important;
    transform: translate(-50%, -50%) scale(1.1);
    box-shadow: 0 0 30px rgba(239, 83, 80, 0.5);
}

.merkle-input {
    position: absolute;
    transform: translate(-50%, -50%);
    width: 100px;
    background: var(--input-bg);
    color: var(--text-color);
    border: 2px solid var(--border-color);
    padding: 12px;
    border-radius: 8px;
    text-align: center;
    font-weight: 600;
    outline: none;
    transition: border-color 0.2s;
    z-index: 3;
}

.merkle-input:focus {
    border-color: var(--accent);
}

.label {
    position: absolute;
    transform: translate(-50%, -50%);
    font-size: 0.7rem;
    font-weight: 700;
    text-transform: uppercase;
    letter-spacing: 0.1em;
    opacity: 0.5;
}

svg {
    position: absolute;
    top: 0;
    left: 0;
    width: 100%;
    height: 100%;
    pointer-events: none;
}

line {
    stroke: var(--border-color);
    stroke-width: 2;
    transition: stroke 0.3s;
}

line.active {
    stroke: var(--accent);
    opacity: 0.8;
}