:root {
    --bg-color: #f4f4f9;
    --panel-bg: #ffffff;
    --border: #d1d5db;
    --text-main: #374151;
    --text-muted: #6b7280;
    --primary: #2563eb;
    --primary-hover: #1d4ed8;
    --active-bg: #dbeafe;
}

* {
    box-sizing: border-box;
    font-family: system-ui, -apple-system, sans-serif;
}

body {
    margin: 0;
    padding: 20px;
    background-color: var(--bg-color);
    color: var(--text-main);
}

.hidden {
    display: none !important;
}

.view {
    max-width: 1100px;
    margin: 0 auto;
}

h1, h2, h3, h4 {
    margin-top: 0;
    color: #111827;
}

.text-center {
    text-align: center;
}

/* Menu */
.menu-header {
    text-align: center;
    margin-bottom: 40px;
}

.menu-grid {
    display: grid;
    grid-template-columns: repeat(auto-fit, minmax(300px, 1fr));
    gap: 20px;
}

.menu-grid button {
    padding: 30px;
    background: var(--panel-bg);
    border: 1px solid var(--border);
    border-radius: 8px;
    text-align: left;
    cursor: pointer;
    transition: box-shadow 0.2s, border-color 0.2s;
}

.menu-grid button:hover {
    box-shadow: 0 4px 6px rgba(0,0,0,0.1);
    border-color: var(--primary);
}

.menu-grid h2 {
    margin: 0 0 10px 0;
    font-size: 1.25rem;
}

.menu-grid p {
    margin: 0;
    color: var(--text-muted);
}

/* Calculator Header */
.header {
    display: flex;
    align-items: center;
    justify-content: space-between;
    margin-bottom: 20px;
    border-bottom: 1px solid var(--border);
    padding-bottom: 15px;
}

.header button {
    padding: 8px 16px;
    margin-bottom: 10px;
    background: #e5e7eb;
    border: none;
    border-radius: 4px;
    cursor: pointer;
    font-weight: 500;
}

.header button:hover {
    background: #d1d5db;
}

.header h2 {
    margin: 0;
    display: inline-block;
    margin-left: 10px;
}

.badge {
    background: var(--active-bg);
    color: var(--primary-hover);
    padding: 6px 12px;
    border-radius: 4px;
    font-family: monospace;
    font-weight: bold;
}

/* Top Section (CVs & Graph) */
.top-section {
    display: flex;
    gap: 15px;
    margin-bottom: 20px;
    flex-wrap: wrap;
}

.cv-panel, .p-value-panel {
    flex: 1;
    background: var(--panel-bg);
    padding: 15px;
    border: 1px solid var(--border);
    border-radius: 8px;
    min-width: 200px;
}

.cv-panel label, .p-value-panel label {
    display: block;
    font-size: 0.85em;
    font-weight: bold;
    color: var(--text-muted);
    margin: 10px 0 5px 0;
    text-transform: uppercase;
}
.cv-panel label:first-child { margin-top: 0; }

input[type="number"], select {
    width: 100%;
    padding: 8px;
    border: 1px solid var(--border);
    border-radius: 4px;
    font-family: monospace;
    font-size: 1rem;
}

#p-value-display {
    font-size: 1.75em;
    font-weight: bold;
    margin: 10px 0;
    font-family: monospace;
    color: #047857;
    background: #d1fae5;
    padding: 10px;
    border-radius: 8px;
}

#p-value-label {
    font-size: 0.8em;
    text-transform: uppercase;
    color: var(--text-muted);
}

/* Canvas */
.canvas-container {
    position: relative;
    background: var(--panel-bg);
    border: 1px solid var(--border);
    border-radius: 8px;
    padding: 10px;
    margin-bottom: 20px;
    overflow: hidden;
}

#canvas {
    width: 100%;
    height: auto;
    max-height: 350px;
    display: block;
}

#dist-label {
    position: absolute;
    top: 15px;
    left: 15px;
    background: rgba(255,255,255,0.9);
    padding: 5px 10px;
    border: 1px solid var(--border);
    border-radius: 4px;
    font-size: 0.85em;
    color: var(--text-muted);
}

/* Main Grid Layout */
.main-grid {
    display: grid;
    grid-template-columns: repeat(auto-fit, minmax(280px, 1fr));
    gap: 20px;
}

.panel {
    background: var(--panel-bg);
    padding: 20px;
    border: 1px solid var(--border);
    border-radius: 8px;
}
.flex-col {
    display: flex;
    flex-direction: column;
}

.panel h3 {
    color: var(--text-muted);
    font-size: 0.9em;
    text-transform: uppercase;
    letter-spacing: 1px;
    border-bottom: 1px solid var(--border);
    padding-bottom: 10px;
    margin-bottom: 15px;
}

/* Formulas */
.formula {
    font-size: 1.5rem;
    font-family: serif;
    font-style: italic;
    margin: 20px 0;
}
.frac {
    display: inline-block;
    vertical-align: middle;
    text-align: center;
}
.frac > span { display: block; padding: 0 5px; }
.frac span.bottom { border-top: 1px solid #000; }

.calc-result {
    background: var(--bg-color);
    padding: 15px;
    border-radius: 8px;
    margin-top: 20px;
}

#calc-stat {
    font-size: 1.75em;
    font-weight: bold;
    font-family: monospace;
    color: var(--primary);
    margin-top: 5px;
}

/* Inputs */
.input-row {
    display: flex;
    align-items: center;
    gap: 15px;
    margin-bottom: 15px;
}

.input-row label {
    width: 40px;
    font-weight: bold;
    font-family: serif;
    font-style: italic;
    font-size: 1.2rem;
    text-align: right;
}

/* Buttons */
.btn-group {
    display: flex;
    gap: 10px;
    margin-bottom: 15px;
}
.btn-group button {
    flex: 1;
    padding: 8px;
    border: 1px solid var(--border);
    background: #f9fafb;
    border-radius: 4px;
    cursor: pointer;
    font-weight: bold;
    color: var(--text-muted);
}
.btn-group button.active {
    background: var(--primary);
    color: white;
    border-color: var(--primary-hover);
}

/* Hypothesis */
.hyp-row {
    display: flex;
    align-items: center;
    gap: 15px;
    margin-bottom: 15px;
    font-size: 1.25rem;
}
.hyp-row label, .hyp-row span:not(.highlight-val) {
    font-family: serif;
    font-style: italic;
    font-weight: bold;
}
.highlight-val {
    background: var(--bg-color);
    padding: 5px 15px;
    border-radius: 4px;
    font-family: monospace;
}

.conclusion {
    margin-top: auto;
    padding-top: 20px;
}
.conclusion h4 {
    font-size: 0.85em;
    color: var(--text-muted);
    text-transform: uppercase;
    margin-bottom: 10px;
}