:root {
    --ink: #17202a;
    --paper: #ffffff;
    --navy: #1e3a8a;
    --cyan: #06b6d4;
    --border: #e2e8f0;
    --text-muted: #64748b;
}

body {
    font-family: system-ui, -apple-system, sans-serif;
    background-color: var(--paper);
    color: var(--ink);
    margin: 0;
    line-height: 1.6;
    padding-bottom: 3rem;
}

.container {
    max-width: 600px;
    margin: 0 auto;
    padding: 0 1rem;
}

header {
    padding: 1.5rem 0;
    border-bottom: 1px solid var(--border);
    margin-bottom: 1.5rem;
    text-align: center;
}

header h1 {
    margin: 0 0 0.25rem 0;
    font-size: 1.5rem;
    color: var(--navy);
}

.subtitle {
    margin: 0;
    color: var(--text-muted);
    font-size: 0.9rem;
    text-transform: uppercase;
    letter-spacing: 0.05em;
}

.instructions h2, .explanation h2 {
    font-size: 1.25rem;
    color: var(--navy);
    margin-bottom: 1rem;
}

.instructions ol {
    padding-left: 1.25rem;
    background: #ffffff;
    border: 1px solid var(--border);
    border-radius: 8px;
    padding: 1.5rem 1.5rem 1.5rem 2.5rem;
}

.instructions li {
    margin-bottom: 0.5rem;
}

.calibration {
    background: #ffffff;
    border: 1px solid var(--border);
    border-left: 4px solid var(--cyan);
    border-radius: 8px;
    padding: 1rem 1.5rem;
    margin-bottom: 2rem;
}

.calibration label {
    display: block;
    font-weight: 600;
    margin-bottom: 0.5rem;
    font-size: 0.9rem;
}

.range-wrapper {
    display: flex;
    align-items: center;
    gap: 1rem;
}

input[type="range"] {
    flex: 1;
    cursor: pointer;
}

#dist-value {
    font-weight: bold;
    color: var(--navy);
    min-width: 50px;
}

.small-text {
    font-size: 0.8rem;
    color: var(--text-muted);
    margin-top: 0.5rem;
    margin-bottom: 0;
}

.experiment-area {
    margin-bottom: 2rem;
    border: 1px dashed var(--border);
    background: #ffffff;
    border-radius: 8px;
    padding: 2rem 0;
    overflow-x: hidden;
    overflow-y: hidden;
}

.canvas-container {
    position: relative;
    height: 100px;
    width: 100%;
}

.target {
    position: absolute;
    top: 50%;
    transform: translateY(-50%);
}

.cross {
    left: 40px;
    color: #e11d48;
    font-size: 3rem;
    font-weight: bold;
    line-height: 1;
    display: flex;
    align-items: center;
    justify-content: center;
}

.dot {
    width: 25px;
    height: 25px;
    background-color: var(--ink);
    border-radius: 50%;
    transition: left 0.1s linear;
}

.explanation {
    background: rgba(30, 58, 138, 0.03);
    padding: 1.5rem;
    border-radius: 8px;
    border: 1px solid var(--border);
}

.explanation p {
    margin-bottom: 1rem;
    font-size: 0.95rem;
}

/* --- CSS DE REFERÊNCIAS --- */
.references { margin-top: 2rem; padding: 1.5rem; background: rgba(15,23,42,0.05); border-radius: 8px; font-size: 0.9rem; text-align: left; }
.references h3 { margin-top: 0; font-size: 1rem; color: var(--text-primary, #17202a); margin-bottom: 0.5rem; }
.references p { margin-bottom: 1rem; color: var(--text-secondary, #475569); }
.references ol { padding-left: 1.5rem; margin-bottom: 1rem; }
.references li { margin-bottom: 0.5rem; color: var(--text-secondary, #475569); }
.references a { color: #0ea5e9; text-decoration: none; font-weight: bold; }
.references .disclaimer { margin-top: 1rem; font-style: italic; color: #64748b; font-size: 0.85rem; border-top: 1px solid rgba(0,0,0,0.1); padding-top: 0.8rem; }