/* ==========================================================================
   ARCHIMEDES' PRINCIPLE — BUOYANCY VIRTUAL LABORATORY STYLESHEET
   ========================================================================== */

:root {
    /* Color Palette - University Engineering Theme */
    --bg-dark: #090d16;
    --bg-card: #121826;
    --bg-card-hover: #172033;
    --bg-input: #1a2338;
    --border-color: rgba(255, 255, 255, 0.08);
    --border-color-highlight: rgba(59, 130, 246, 0.4);

    --text-primary: #f8fafc;
    --text-secondary: #94a3b8;
    --text-muted: #64748b;

    /* Primary Accent Colors */
    --accent-blue: #3b82f6;
    --accent-cyan: #0ea5e9;
    --accent-green: #10b981;
    --accent-amber: #f59e0b;
    --accent-red: #ef4444;
    --accent-purple: #8b5cf6;

    /* State Colors */
    --state-float-bg: rgba(16, 185, 129, 0.15);
    --state-float-border: #10b981;
    --state-sink-bg: rgba(239, 68, 68, 0.15);
    --state-sink-border: #ef4444;
    --state-suspend-bg: rgba(14, 165, 233, 0.15);
    --state-suspend-border: #0ea5e9;

    /* Typography */
    --font-main: 'Inter', system-ui, -apple-system, sans-serif;
    --font-heading: 'Outfit', 'Inter', system-ui, sans-serif;
    --font-mono: 'JetBrains Mono', monospace;

    /* Layout & Shadows */
    --radius-sm: 6px;
    --radius-md: 10px;
    --radius-lg: 16px;
    --shadow-card: 0 10px 30px -5px rgba(0, 0, 0, 0.5);
    --shadow-glow: 0 0 20px rgba(59, 130, 246, 0.2);
}

/* Reset & Global Base Styles */
*, *::before, *::after {
    box-sizing: border-box;
    margin: 0;
    padding: 0;
}

body {
    background-color: var(--bg-dark);
    color: var(--text-primary);
    font-family: var(--font-main);
    line-height: 1.5;
    min-height: 100vh;
    overflow-x: hidden;
    background-image: 
        radial-gradient(circle at 15% 15%, rgba(14, 165, 233, 0.05) 0%, transparent 40%),
        radial-gradient(circle at 85% 85%, rgba(59, 130, 246, 0.05) 0%, transparent 40%);
}

.app-container {
    max-width: 1440px;
    margin: 0 auto;
    padding: 16px 24px;
    display: flex;
    flex-direction: column;
    gap: 20px;
}

/* ==========================================================================
   HEADER SECTION
   ========================================================================== */
.app-header {
    background: var(--bg-card);
    border: 1px solid var(--border-color);
    border-radius: var(--radius-lg);
    padding: 16px 24px;
    display: flex;
    justify-content: space-between;
    align-items: center;
    flex-wrap: wrap;
    gap: 16px;
    box-shadow: var(--shadow-card);
}

.header-brand {
    display: flex;
    align-items: center;
    gap: 16px;
}

.logo-icon {
    width: 48px;
    height: 48px;
    background: linear-gradient(135deg, rgba(14, 165, 233, 0.2), rgba(59, 130, 246, 0.2));
    border: 1px solid var(--border-color-highlight);
    border-radius: var(--radius-md);
    display: flex;
    align-items: center;
    justify-content: center;
    color: var(--accent-cyan);
}

.header-titles h1 {
    font-family: var(--font-heading);
    font-size: 1.45rem;
    font-weight: 700;
    color: #ffffff;
    letter-spacing: 0.02em;
    text-transform: uppercase;
}

.header-titles .subtitle {
    font-size: 0.82rem;
    color: var(--text-secondary);
    letter-spacing: 0.05em;
    text-transform: uppercase;
}

/* Experiment Mode Buttons */
.experiment-modes {
    display: flex;
    align-items: center;
    gap: 12px;
}

.mode-label {
    font-size: 0.85rem;
    color: var(--text-muted);
    font-weight: 500;
    text-transform: uppercase;
    letter-spacing: 0.05em;
}

.mode-buttons {
    display: flex;
    background: var(--bg-input);
    padding: 4px;
    border-radius: var(--radius-md);
    border: 1px solid var(--border-color);
    gap: 4px;
}

.mode-btn {
    background: transparent;
    border: none;
    color: var(--text-secondary);
    padding: 8px 14px;
    border-radius: var(--radius-sm);
    cursor: pointer;
    font-family: var(--font-main);
    font-size: 0.82rem;
    font-weight: 500;
    display: flex;
    flex-direction: column;
    align-items: center;
    transition: all 0.2s ease;
}

.mode-btn .mode-num {
    font-size: 0.7rem;
    opacity: 0.7;
    text-transform: uppercase;
}

.mode-btn:hover {
    color: var(--text-primary);
    background: rgba(255, 255, 255, 0.05);
}

.mode-btn.active {
    background: var(--accent-blue);
    color: #ffffff;
    box-shadow: 0 4px 12px rgba(59, 130, 246, 0.3);
}

/* ==========================================================================
   MAIN WORKSPACE GRID
   ========================================================================== */
.main-workspace {
    display: grid;
    grid-template-columns: 1.2fr 0.8fr;
    gap: 20px;
}

@media (max-width: 1150px) {
    .main-workspace {
        grid-template-columns: 1fr;
    }
}

/* Cards Generic Base */
.card, .sim-card {
    background: var(--bg-card);
    border: 1px solid var(--border-color);
    border-radius: var(--radius-lg);
    box-shadow: var(--shadow-card);
    overflow: hidden;
}

.card-header, .sim-header {
    padding: 16px 20px;
    border-bottom: 1px solid var(--border-color);
    display: flex;
    justify-content: space-between;
    align-items: center;
}

.card-header h3, .sim-title h2 {
    font-family: var(--font-heading);
    font-size: 1.15rem;
    font-weight: 700;
    color: #ffffff;
    letter-spacing: 0.03em;
    text-transform: uppercase;
}

.sim-title {
    display: flex;
    align-items: center;
    gap: 10px;
}

.pulse-indicator {
    width: 10px;
    height: 10px;
    background: var(--accent-green);
    border-radius: 50%;
    box-shadow: 0 0 10px var(--accent-green);
    animation: pulse 2s infinite;
}

@keyframes pulse {
    0% { opacity: 0.4; }
    50% { opacity: 1; transform: scale(1.1); }
    100% { opacity: 0.4; }
}

/* Status Badge */
.status-badge {
    padding: 6px 14px;
    border-radius: 20px;
    font-size: 0.75rem;
    font-weight: 700;
    letter-spacing: 0.05em;
    text-transform: uppercase;
}

.state-float {
    background: var(--state-float-bg);
    color: var(--accent-green);
    border: 1px solid var(--state-float-border);
}

.state-sink {
    background: var(--state-sink-bg);
    color: var(--accent-red);
    border: 1px solid var(--state-sink-border);
}

.state-suspended {
    background: var(--state-suspend-bg);
    color: var(--accent-cyan);
    border: 1px solid var(--state-suspend-border);
}

/* ==========================================================================
   SIMULATION CANVAS VIEWPORT
   ========================================================================== */
.sim-viewport-wrapper {
    position: relative;
    background: #090e17;
    width: 100%;
    display: flex;
    justify-content: center;
    align-items: center;
    border-bottom: 1px solid var(--border-color);
}

#simCanvas {
    display: block;
    width: 100%;
    height: auto;
    max-height: 540px;
}

/* Canvas Legend Overlay */
.canvas-legend {
    position: absolute;
    top: 14px;
    left: 14px;
    background: rgba(15, 23, 42, 0.85);
    backdrop-filter: blur(8px);
    border: 1px solid var(--border-color);
    border-radius: var(--radius-md);
    padding: 10px 14px;
    display: flex;
    flex-direction: column;
    gap: 6px;
    font-size: 0.78rem;
}

.legend-item {
    display: flex;
    align-items: center;
    gap: 8px;
    color: var(--text-secondary);
}

.legend-color {
    width: 14px;
    height: 3px;
    border-radius: 2px;
}

.vector-weight { background-color: var(--accent-red); }
.vector-buoyant { background-color: var(--accent-green); }
.vector-tension { background-color: var(--accent-amber); }

/* Viewport Controls */
.viewport-controls {
    position: absolute;
    top: 14px;
    right: 14px;
    display: flex;
    gap: 8px;
}

.icon-toggle {
    background: rgba(15, 23, 42, 0.85);
    border: 1px solid var(--border-color);
    color: var(--text-secondary);
    padding: 6px 12px;
    border-radius: var(--radius-sm);
    font-size: 0.75rem;
    cursor: pointer;
    display: flex;
    align-items: center;
    gap: 6px;
    transition: all 0.2s;
}

.icon-toggle:hover {
    color: var(--text-primary);
    border-color: var(--border-color-highlight);
}

.icon-toggle.active {
    background: rgba(59, 130, 246, 0.2);
    border-color: var(--accent-blue);
    color: var(--accent-blue);
}

/* Action Control Bar */
.action-bar {
    padding: 14px 20px;
    display: flex;
    gap: 12px;
    justify-content: center;
    background: var(--bg-card);
    border-bottom: 1px solid var(--border-color);
    flex-wrap: wrap;
}

.btn {
    padding: 10px 20px;
    border-radius: var(--radius-md);
    font-family: var(--font-main);
    font-size: 0.88rem;
    font-weight: 600;
    cursor: pointer;
    border: none;
    display: flex;
    align-items: center;
    gap: 8px;
    transition: all 0.2s ease;
}

.btn:active {
    transform: translateY(1px);
}

.btn-primary {
    background: linear-gradient(135deg, #2563eb, #3b82f6);
    color: #ffffff;
    box-shadow: 0 4px 14px rgba(37, 99, 235, 0.4);
}

.btn-primary:hover {
    background: linear-gradient(135deg, #1d4ed8, #2563eb);
    box-shadow: 0 6px 18px rgba(37, 99, 235, 0.5);
}

.btn-secondary {
    background: var(--bg-input);
    color: var(--text-primary);
    border: 1px solid var(--border-color);
}

.btn-secondary:hover {
    background: rgba(255, 255, 255, 0.08);
    border-color: var(--border-color-highlight);
}

.btn-danger {
    background: rgba(239, 68, 68, 0.15);
    color: var(--accent-red);
    border: 1px solid rgba(239, 68, 68, 0.3);
}

.btn-danger:hover {
    background: rgba(239, 68, 68, 0.25);
}

.btn-success {
    background: linear-gradient(135deg, #059669, #10b981);
    color: #ffffff;
    box-shadow: 0 4px 14px rgba(16, 185, 129, 0.3);
}

.btn-success:hover {
    background: linear-gradient(135deg, #047857, #059669);
}

.btn-outline {
    background: transparent;
    border: 1px solid var(--border-color);
    color: var(--text-secondary);
}

.btn-outline:hover {
    color: var(--text-primary);
    border-color: var(--text-secondary);
}

.btn-outline-danger {
    background: transparent;
    border: 1px solid rgba(239, 68, 68, 0.4);
    color: var(--accent-red);
}

.btn-outline-danger:hover {
    background: rgba(239, 68, 68, 0.1);
}

/* Verification Banner & Force Comparison Bars */
.verification-card {
    padding: 18px 20px;
    display: flex;
    flex-direction: column;
    gap: 14px;
    background: rgba(15, 23, 42, 0.4);
}

.force-comparison-container {
    display: grid;
    grid-template-columns: 1fr 1fr;
    gap: 16px;
}

@media (max-width: 600px) {
    .force-comparison-container {
        grid-template-columns: 1fr;
    }
}

.force-bar-group {
    display: flex;
    flex-direction: column;
    gap: 6px;
}

.force-bar-header {
    display: flex;
    justify-content: space-between;
    font-size: 0.78rem;
    color: var(--text-secondary);
    font-weight: 600;
}

.force-bar-track {
    height: 12px;
    background: var(--bg-input);
    border-radius: 6px;
    overflow: hidden;
    border: 1px solid var(--border-color);
}

.force-bar-fill {
    height: 100%;
    width: 0%;
    border-radius: 6px;
    transition: width 0.15s ease-out;
}

.fill-buoyant {
    background: linear-gradient(90deg, #059669, #10b981);
}

.fill-weight {
    background: linear-gradient(90deg, #dc2626, #ef4444);
}

/* Verification Status Pill */
.verification-status {
    padding: 10px 16px;
    border-radius: var(--radius-md);
    font-size: 0.85rem;
    font-weight: 600;
    display: flex;
    align-items: center;
    gap: 10px;
    transition: all 0.3s;
}

.verification-status.verified {
    background: rgba(16, 185, 129, 0.15);
    border: 1px solid var(--accent-green);
    color: var(--accent-green);
}

.verification-status.unverified {
    background: rgba(148, 163, 184, 0.08);
    border: 1px solid var(--border-color);
    color: var(--text-secondary);
}

.verification-status.unbalanced {
    background: rgba(239, 68, 68, 0.12);
    border: 1px solid var(--accent-red);
    color: var(--accent-red);
}

/* ==========================================================================
   RIGHT COLUMN: CONTROLS & TELEMETRY
   ========================================================================== */
.controls-column {
    display: flex;
    flex-direction: column;
    gap: 20px;
}

.presets-grid {
    padding: 16px 20px;
    display: grid;
    grid-template-columns: 1fr 1fr;
    gap: 14px;
}

@media (max-width: 600px) {
    .presets-grid {
        grid-template-columns: 1fr;
    }
}

.preset-group {
    display: flex;
    flex-direction: column;
    gap: 6px;
}

.preset-group label {
    font-size: 0.8rem;
    color: var(--text-secondary);
    font-weight: 500;
}

.form-select {
    background: var(--bg-input);
    border: 1px solid var(--border-color);
    color: var(--text-primary);
    padding: 9px 12px;
    border-radius: var(--radius-sm);
    font-family: var(--font-main);
    font-size: 0.85rem;
    outline: none;
    cursor: pointer;
    transition: border-color 0.2s;
}

.form-select:focus {
    border-color: var(--accent-blue);
}

/* Parameters Card & Sliders */
.mode-indicator-badge {
    font-size: 0.75rem;
    background: rgba(59, 130, 246, 0.15);
    color: var(--accent-blue);
    padding: 4px 10px;
    border-radius: 12px;
    border: 1px solid rgba(59, 130, 246, 0.3);
    font-weight: 600;
}

.sliders-container {
    padding: 16px 20px;
    display: flex;
    flex-direction: column;
    gap: 18px;
}

.control-group {
    display: flex;
    flex-direction: column;
    gap: 8px;
}

.control-header {
    display: flex;
    justify-content: space-between;
    align-items: center;
}

.control-header label {
    font-size: 0.85rem;
    color: var(--text-primary);
    font-weight: 500;
}

.number-input-wrap {
    display: flex;
    align-items: center;
    background: var(--bg-input);
    border: 1px solid var(--border-color);
    border-radius: var(--radius-sm);
    padding: 2px 8px;
    gap: 4px;
}

.number-input-wrap input[type="number"] {
    background: transparent;
    border: none;
    color: #ffffff;
    font-family: var(--font-mono);
    font-size: 0.88rem;
    font-weight: 600;
    width: 68px;
    text-align: right;
    outline: none;
}

.number-input-wrap .unit {
    font-size: 0.78rem;
    color: var(--text-muted);
    font-weight: 500;
}

.number-input-wrap .sub-unit {
    font-size: 0.75rem;
    color: var(--accent-cyan);
    margin-left: 4px;
}

/* Range Inputs styling */
.form-range {
    -webkit-appearance: none;
    width: 100%;
    height: 6px;
    background: var(--bg-input);
    border-radius: 3px;
    outline: none;
}

.form-range::-webkit-slider-thumb {
    -webkit-appearance: none;
    width: 18px;
    height: 18px;
    border-radius: 50%;
    background: var(--accent-blue);
    cursor: pointer;
    box-shadow: 0 0 10px rgba(59, 130, 246, 0.5);
    border: 2px solid #ffffff;
    transition: transform 0.1s;
}

.form-range::-webkit-slider-thumb:hover {
    transform: scale(1.15);
}

.range-ticks {
    display: flex;
    justify-content: space-between;
    font-size: 0.7rem;
    color: var(--text-muted);
}

/* Calculated Density Banner */
.density-calc-banner {
    background: rgba(15, 23, 42, 0.6);
    border: 1px dashed var(--border-color-highlight);
    border-radius: var(--radius-md);
    padding: 10px 14px;
    display: flex;
    align-items: center;
    justify-content: space-between;
    flex-wrap: wrap;
    gap: 8px;
    font-size: 0.82rem;
}

.density-calc-banner strong {
    font-family: var(--font-mono);
    font-size: 0.95rem;
    color: var(--accent-cyan);
}

.ratio-badge {
    padding: 3px 8px;
    border-radius: 10px;
    font-size: 0.72rem;
    font-weight: 600;
}

.ratio-float {
    background: rgba(16, 185, 129, 0.15);
    color: var(--accent-green);
}

.ratio-sink {
    background: rgba(239, 68, 68, 0.15);
    color: var(--accent-red);
}

.ratio-suspend {
    background: rgba(14, 165, 233, 0.15);
    color: var(--accent-cyan);
}

/* Gravity Chips */
.gravity-presets {
    display: flex;
    gap: 6px;
    margin-top: 4px;
}

.preset-chip {
    background: var(--bg-input);
    border: 1px solid var(--border-color);
    color: var(--text-muted);
    font-size: 0.72rem;
    padding: 4px 10px;
    border-radius: 12px;
    cursor: pointer;
    transition: all 0.2s;
}

.preset-chip:hover {
    color: var(--text-primary);
}

.preset-chip.active {
    background: rgba(59, 130, 246, 0.2);
    border-color: var(--accent-blue);
    color: var(--accent-blue);
    font-weight: 600;
}

/* Telemetry Grid */
.live-tag {
    background: rgba(239, 68, 68, 0.2);
    color: var(--accent-red);
    border: 1px solid rgba(239, 68, 68, 0.4);
    font-size: 0.65rem;
    padding: 2px 6px;
    border-radius: 4px;
    font-weight: 700;
    letter-spacing: 0.05em;
}

.telemetry-grid {
    padding: 16px 20px;
    display: grid;
    grid-template-columns: repeat(2, 1fr);
    gap: 12px;
}

@media (max-width: 480px) {
    .telemetry-grid {
        grid-template-columns: 1fr;
    }
}

.metric-card {
    background: var(--bg-input);
    border: 1px solid var(--border-color);
    border-radius: var(--radius-md);
    padding: 10px 14px;
    display: flex;
    flex-direction: column;
    gap: 4px;
}

.metric-label {
    font-size: 0.74rem;
    color: var(--text-secondary);
    font-weight: 500;
}

.metric-value {
    font-family: var(--font-mono);
    font-size: 1.1rem;
    font-weight: 600;
    color: #ffffff;
}

.metric-unit {
    font-size: 0.75rem;
    color: var(--text-muted);
    font-weight: 400;
}

.metric-sub {
    font-size: 0.72rem;
    color: var(--accent-cyan);
    font-family: var(--font-mono);
}

.highlight-metric {
    background: rgba(14, 165, 233, 0.08);
    border-color: rgba(14, 165, 233, 0.3);
}

.vector-weight-card {
    border-left: 3px solid var(--accent-red);
}

.vector-buoyant-card {
    border-left: 3px solid var(--accent-green);
}

.state-card {
    grid-column: span 2;
    background: rgba(15, 23, 42, 0.7);
    border-color: var(--border-color-highlight);
    align-items: center;
    text-align: center;
}

@media (max-width: 480px) {
    .state-card {
        grid-column: span 1;
    }
}

.state-text {
    font-family: var(--font-heading);
    font-size: 1.15rem;
    font-weight: 700;
    letter-spacing: 0.05em;
    color: var(--accent-green);
}

/* ==========================================================================
   SECONDARY SECTION: TABLE & THEORY
   ========================================================================== */
.secondary-workspace {
    display: flex;
    flex-direction: column;
    gap: 20px;
}

.table-header {
    flex-wrap: wrap;
    gap: 16px;
}

.table-subtitle {
    font-size: 0.82rem;
    color: var(--text-secondary);
}

.table-actions {
    display: flex;
    gap: 8px;
    flex-wrap: wrap;
}

.table-responsive {
    width: 100%;
    overflow-x: auto;
}

.observation-table {
    width: 100%;
    border-collapse: collapse;
    font-size: 0.84rem;
    text-align: left;
}

.observation-table th {
    background: var(--bg-input);
    color: var(--text-secondary);
    padding: 12px 14px;
    font-weight: 600;
    border-bottom: 1px solid var(--border-color);
    white-space: nowrap;
}

.observation-table td {
    padding: 12px 14px;
    border-bottom: 1px solid var(--border-color);
    color: var(--text-primary);
    font-family: var(--font-mono);
    font-size: 0.8rem;
    white-space: nowrap;
}

.observation-table tbody tr:hover {
    background: var(--bg-card-hover);
}

.empty-row td {
    text-align: center;
    color: var(--text-muted);
    font-family: var(--font-main);
    padding: 24px;
}

.btn-remove-row {
    background: transparent;
    border: none;
    color: var(--accent-red);
    cursor: pointer;
    font-size: 1rem;
    padding: 2px 6px;
    border-radius: 4px;
    transition: background 0.2s;
}

.btn-remove-row:hover {
    background: rgba(239, 68, 68, 0.2);
}

/* Theory & Procedure Grid */
.theory-grid {
    display: grid;
    grid-template-columns: 1fr 1fr;
    gap: 20px;
}

@media (max-width: 900px) {
    .theory-grid {
        grid-template-columns: 1fr;
    }
}

.procedure-list {
    padding: 20px 24px 20px 40px;
    display: flex;
    flex-direction: column;
    gap: 12px;
    color: var(--text-secondary);
    font-size: 0.88rem;
}

.procedure-list li::marker {
    color: var(--accent-blue);
    font-weight: 700;
}

.procedure-list mark {
    background: rgba(59, 130, 246, 0.2);
    color: var(--accent-blue);
    padding: 2px 6px;
    border-radius: 4px;
    font-weight: 600;
}

.theory-content {
    padding: 20px;
    display: flex;
    flex-direction: column;
    gap: 14px;
    color: var(--text-secondary);
    font-size: 0.88rem;
}

.theory-content h4 {
    color: var(--text-primary);
    font-family: var(--font-heading);
    font-size: 0.95rem;
    margin-top: 4px;
}

.formula-box {
    background: var(--bg-input);
    border: 1px solid var(--border-color-highlight);
    border-radius: var(--radius-md);
    padding: 12px 16px;
    text-align: center;
    color: #ffffff;
    font-size: 1.05rem;
}

.bullet-list {
    padding-left: 20px;
    display: flex;
    flex-direction: column;
    gap: 8px;
}

.applications-pills {
    display: flex;
    flex-wrap: wrap;
    gap: 8px;
    margin-top: 4px;
}

.app-pill {
    background: rgba(14, 165, 233, 0.1);
    border: 1px solid rgba(14, 165, 233, 0.3);
    color: var(--accent-cyan);
    padding: 6px 12px;
    border-radius: 16px;
    font-size: 0.78rem;
    font-weight: 500;
}

/* Footer */
.app-footer {
    text-align: center;
    padding: 16px;
    color: var(--text-muted);
    font-size: 0.8rem;
    border-top: 1px solid var(--border-color);
    margin-top: 20px;
}