/* ================================================================
   ArcSec Matcher — Telescope Image Scale & FOV Calculator
   Bespoke Midnight Observatory Theme (Dark Navy / Cyan / Deep Purple)
   ================================================================ */

:root {
    --bg-primary: #090d16;
    --bg-surface: #111827;
    --bg-card: #1f293d;
    --bg-hover: #2a3854;
    --text-primary: #f8fafc;
    --text-secondary: #94a3b8;
    --text-muted: #64748b;
    
    --accent-cyan: #38bdf8;
    --accent-cyan-glow: rgba(56, 189, 248, 0.25);
    --accent-purple: #c084fc;
    --accent-purple-glow: rgba(192, 132, 252, 0.25);
    
    --border-color: #1e293b;
    --border-highlight: #334155;
    
    --state-undersampled: #f59e0b;
    --state-optimal: #22c55e;
    --state-oversampled: #38bdf8;
    
    --font-heading: 'Outfit', sans-serif;
    --font-body: 'Inter', sans-serif;
    --font-mono: 'JetBrains Mono', monospace;
}

body {
    background-color: var(--bg-primary);
    color: var(--text-primary);
    font-family: var(--font-body);
    line-height: 1.6;
    margin: 0;
    padding: 0;
}

/* App Header */
.app-header {
    background: linear-gradient(180deg, rgba(15, 23, 42, 0.9) 0%, rgba(9, 13, 22, 1) 100%);
    border-bottom: 1px solid var(--border-color);
    padding: 2.5rem 1rem 2rem;
    text-align: center;
}

.header-inner {
    max-width: 800px;
    margin: 0 auto;
}

.brand-badge {
    display: inline-block;
    padding: 0.25rem 0.75rem;
    background: rgba(56, 189, 248, 0.1);
    border: 1px solid rgba(56, 189, 248, 0.25);
    border-radius: 9999px;
    color: var(--accent-cyan);
    font-size: 0.85rem;
    font-weight: 600;
    margin-bottom: 0.75rem;
}

.app-header h1 {
    font-family: var(--font-heading);
    font-size: 2.5rem;
    font-weight: 800;
    color: var(--text-primary);
    margin: 0 0 0.5rem 0;
    letter-spacing: -0.02em;
    background: linear-gradient(135deg, #ffffff 30%, var(--accent-cyan) 100%);
    -webkit-background-clip: text;
    -webkit-text-fill-color: transparent;
}

.app-header p {
    color: var(--text-secondary);
    font-size: 1.1rem;
    margin: 0;
}

/* Main Container */
.container {
    max-width: 1200px;
    margin: 0 auto;
    padding: 1.5rem;
}

/* Layout Grid */
.calculator-grid {
    display: grid;
    grid-template-columns: 1fr;
    gap: 1.5rem;
    margin-top: 1.5rem;
}

@media (min-width: 900px) {
    .calculator-grid {
        grid-template-columns: 480px 1fr;
    }
}

/* Card Styling */
.calc-card {
    background-color: var(--bg-surface);
    border: 1px solid var(--border-color);
    border-radius: 1rem;
    padding: 1.75rem;
    box-shadow: 0 10px 25px -5px rgba(0, 0, 0, 0.4);
}

.card-title {
    font-family: var(--font-heading);
    font-size: 1.35rem;
    font-weight: 700;
    color: var(--text-primary);
    margin: 0 0 1.5rem 0;
    display: flex;
    align-items: center;
    gap: 0.5rem;
}

.title-icon {
    width: 22px;
    height: 22px;
    color: var(--accent-cyan);
}

/* Form Controls */
.form-group {
    margin-bottom: 1.25rem;
}

.form-group label {
    display: block;
    font-size: 0.875rem;
    font-weight: 600;
    color: var(--text-secondary);
    margin-bottom: 0.5rem;
}

.form-input,
.form-select {
    width: 100%;
    padding: 0.75rem 1rem;
    background-color: var(--bg-card);
    border: 1px solid var(--border-color);
    border-radius: 0.5rem;
    color: var(--text-primary);
    font-family: var(--font-body);
    font-size: 1rem;
    box-sizing: border-box;
    transition: border-color 0.2s, box-shadow 0.2s;
}

.form-input:focus,
.form-select:focus {
    outline: none;
    border-color: var(--accent-cyan);
    box-shadow: 0 0 0 3px var(--accent-cyan-glow);
}

.form-row.dual-row {
    display: grid;
    grid-template-columns: 1fr 1fr;
    gap: 1rem;
}

.divider {
    border: 0;
    height: 1px;
    background: var(--border-color);
    margin: 1.5rem 0;
}

/* Gauge Section */
.gauge-container {
    background-color: var(--bg-card);
    border: 1px solid var(--border-color);
    border-radius: 0.75rem;
    padding: 1.25rem;
    text-align: center;
    margin-bottom: 1.5rem;
}

.gauge-wrapper {
    position: relative;
    display: inline-block;
    width: 300px;
    max-width: 100%;
}

#gaugeCanvas {
    display: block;
    margin: 0 auto;
}

.gauge-value-display {
    position: absolute;
    bottom: 10px;
    left: 50%;
    transform: translateX(-50%);
    text-align: center;
}

.gauge-number {
    display: block;
    font-family: var(--font-mono);
    font-size: 2.25rem;
    font-weight: 700;
    color: var(--text-primary);
    line-height: 1;
}

.gauge-unit {
    font-size: 0.85rem;
    color: var(--text-muted);
    font-weight: 500;
}

/* Verdict Badge */
.verdict-badge {
    display: flex;
    align-items: flex-start;
    gap: 0.75rem;
    padding: 1rem;
    border-radius: 0.5rem;
    text-align: left;
    margin-top: 1rem;
    transition: all 0.3s ease;
}

.verdict-icon {
    font-size: 1.5rem;
    line-height: 1;
}

.verdict-text strong {
    display: block;
    font-family: var(--font-heading);
    font-size: 1.1rem;
    font-weight: 700;
}

.verdict-text p {
    margin: 0.25rem 0 0 0;
    font-size: 0.875rem;
    line-height: 1.4;
    color: rgba(255, 255, 255, 0.85);
}

.verdict-undersampled {
    background-color: rgba(245, 158, 11, 0.15);
    border: 1px solid rgba(245, 158, 11, 0.4);
    color: #fbbf24;
}

.verdict-optimal {
    background-color: rgba(34, 197, 94, 0.15);
    border: 1px solid rgba(34, 197, 94, 0.4);
    color: #4ade80;
}

.verdict-oversampled {
    background-color: rgba(56, 189, 248, 0.15);
    border: 1px solid rgba(56, 189, 248, 0.4);
    color: #7dd3fc;
}

/* Metrics Grid */
.metrics-grid {
    display: grid;
    grid-template-columns: repeat(auto-fit, minmax(180px, 1fr));
    gap: 1rem;
    margin-bottom: 1.5rem;
}

.metric-box {
    background-color: var(--bg-card);
    border: 1px solid var(--border-color);
    border-radius: 0.5rem;
    padding: 1rem;
    display: flex;
    flex-direction: column;
}

.metric-label {
    font-size: 0.8rem;
    font-weight: 600;
    color: var(--text-muted);
    text-transform: uppercase;
    letter-spacing: 0.05em;
    margin-bottom: 0.25rem;
}

.metric-value {
    font-family: var(--font-mono);
    font-size: 1.25rem;
    font-weight: 700;
    color: var(--text-primary);
}

.metric-sub {
    font-size: 0.8rem;
    color: var(--accent-cyan);
    margin-top: 0.25rem;
}

/* Visualizer Container */
.visualizer-container {
    background-color: var(--bg-card);
    border: 1px solid var(--border-color);
    border-radius: 0.75rem;
    padding: 1.25rem;
    margin-bottom: 1.5rem;
}

.visualizer-header {
    margin-bottom: 0.75rem;
}

.visualizer-header h3 {
    font-family: var(--font-heading);
    font-size: 1.1rem;
    font-weight: 700;
    margin: 0;
}

.visualizer-subtitle {
    font-size: 0.8rem;
    color: var(--text-muted);
}

.canvas-wrapper {
    width: 100%;
    overflow-x: auto;
    border: 1px solid var(--border-color);
    border-radius: 0.5rem;
    background: #04060a;
}

#starGridCanvas {
    display: block;
    width: 100%;
    height: auto;
    max-height: 240px;
}

.canvas-legend {
    display: flex;
    justify-content: center;
    gap: 1.5rem;
    margin-top: 0.75rem;
    font-size: 0.85rem;
    color: var(--text-secondary);
}

.legend-item {
    display: flex;
    align-items: center;
    gap: 0.4rem;
}

.legend-dot {
    width: 10px;
    height: 10px;
    border-radius: 50%;
}

.dot-pixel {
    background-color: #1e293b;
    border: 1px solid var(--accent-cyan);
}

.dot-star {
    background-color: #f43f5e;
    box-shadow: 0 0 8px #f43f5e;
}

/* Advice Card */
.advice-card {
    background: rgba(56, 189, 248, 0.08);
    border: 1px solid rgba(56, 189, 248, 0.2);
    border-radius: 0.5rem;
    padding: 1rem 1.25rem;
}

.advice-card h4 {
    font-family: var(--font-heading);
    font-size: 1rem;
    font-weight: 700;
    color: var(--accent-cyan);
    margin: 0 0 0.4rem 0;
}

.advice-card p {
    font-size: 0.9rem;
    color: var(--text-secondary);
    margin: 0;
    line-height: 1.5;
}

/* Explanatory Article */
.explanatory-article {
    margin-top: 3rem;
    background-color: var(--bg-surface);
    border: 1px solid var(--border-color);
    border-radius: 1rem;
    padding: 2rem;
}

.explanatory-article h2 {
    font-family: var(--font-heading);
    font-size: 1.8rem;
    font-weight: 700;
    color: var(--text-primary);
    margin-top: 0;
    margin-bottom: 1.5rem;
    border-bottom: 1px solid var(--border-color);
    padding-bottom: 0.75rem;
}

.guide-grid {
    display: grid;
    grid-template-columns: 1fr;
    gap: 2rem;
    margin-bottom: 2rem;
}

@media (min-width: 768px) {
    .guide-grid {
        grid-template-columns: 1fr 1fr;
    }
}

.guide-block h3 {
    font-family: var(--font-heading);
    font-size: 1.25rem;
    font-weight: 700;
    color: var(--accent-cyan);
    margin-top: 0;
    margin-bottom: 0.75rem;
}

.math-callout {
    background-color: var(--bg-card);
    border-left: 3px solid var(--accent-cyan);
    padding: 0.75rem 1rem;
    font-family: var(--font-mono);
    font-size: 0.95rem;
    color: var(--text-primary);
    margin: 1rem 0;
    overflow-x: auto;
}

.sampling-states-guide {
    margin-top: 2rem;
}

.sampling-states-guide h3 {
    font-family: var(--font-heading);
    font-size: 1.4rem;
    font-weight: 700;
    margin-bottom: 1rem;
}

.states-grid {
    display: grid;
    grid-template-columns: 1fr;
    gap: 1rem;
}

@media (min-width: 768px) {
    .states-grid {
        grid-template-columns: repeat(3, 1fr);
    }
}

.state-card {
    background-color: var(--bg-card);
    border: 1px solid var(--border-color);
    border-radius: 0.75rem;
    padding: 1.25rem;
}

.state-card h4 {
    font-family: var(--font-heading);
    font-size: 1.1rem;
    font-weight: 700;
    margin-top: 0;
    margin-bottom: 0.75rem;
}

.state-undersampled h4 { color: #fbbf24; }
.state-optimal h4 { color: #4ade80; }
.state-oversampled h4 { color: #7dd3fc; }

.state-card p {
    font-size: 0.875rem;
    color: var(--text-secondary);
    margin: 0 0 0.5rem 0;
}