*,
*::before,
*::after {
    margin: 0;
    padding: 0;
    box-sizing: border-box;
}

:root {
    --bg-primary: #0a0e17;
    --bg-card: rgba(16, 22, 36, 0.85);
    --bg-card-hover: rgba(22, 30, 50, 0.9);
    --border: rgba(99, 140, 255, 0.12);
    --border-glow: rgba(99, 140, 255, 0.25);
    --text-primary: #e2e8f4;
    --text-secondary: #8892a8;
    --text-muted: #5a6478;
    --accent: #638cff;
    --accent-bright: #8eaaff;
    --accent-glow: rgba(99, 140, 255, 0.15);
    --success: #34d399;
    --warning: #fbbf24;
    --danger: #f87171;
    --radius: 14px;
    --radius-sm: 8px;
    --transition: 0.25s cubic-bezier(0.4, 0, 0.2, 1);
    --font: 'Inter', -apple-system, BlinkMacSystemFont, sans-serif;
}

html {
    font-size: 15px;
    scroll-behavior: smooth;
}

body {
    font-family: var(--font);
    background: var(--bg-primary);
    color: var(--text-primary);
    min-height: 100vh;
    line-height: 1.6;
    background-image:
        radial-gradient(circle at 1px 1px, rgba(99, 140, 255, 0.04) 1px, transparent 0);
    background-size: 28px 28px;
}

.header {
    border-bottom: 1px solid var(--border);
    backdrop-filter: blur(20px);
    position: sticky;
    top: 0;
    z-index: 100;
    background: rgba(10, 14, 23, 0.9);
}

.header-inner {
    max-width: 1200px;
    margin: 0 auto;
    padding: 1.2rem 2rem;
    display: flex;
    align-items: center;
    justify-content: space-between;
}

.logo {
    display: flex;
    align-items: center;
    gap: 0.75rem;
}

.logo-icon {
    font-size: 1.6rem;
    color: var(--accent);
    animation: pulse-glow 3s ease-in-out infinite;
}

@keyframes pulse-glow {

    0%,
    100% {
        text-shadow: 0 0 8px var(--accent-glow);
    }

    50% {
        text-shadow: 0 0 20px rgba(99, 140, 255, 0.4);
    }
}

.logo h1 {
    font-size: 1.25rem;
    font-weight: 600;
    letter-spacing: -0.02em;
}

.subtitle {
    color: var(--text-muted);
    font-size: 0.8rem;
    font-weight: 400;
    letter-spacing: 0.02em;
}

.main {
    max-width: 1200px;
    margin: 0 auto;
    padding: 2rem;
    display: flex;
    flex-direction: column;
    gap: 1.5rem;
}

.card {
    background: var(--bg-card);
    border: 1px solid var(--border);
    border-radius: var(--radius);
    padding: 1.5rem;
    backdrop-filter: blur(12px);
    transition: border-color var(--transition), box-shadow var(--transition);
}

.card:hover {
    border-color: var(--border-glow);
    box-shadow: 0 4px 30px rgba(99, 140, 255, 0.06);
}

.controls-grid {
    display: grid;
    grid-template-columns: repeat(auto-fit, minmax(160px, 1fr));
    gap: 1rem;
    align-items: end;
}

.control-group {
    display: flex;
    flex-direction: column;
    gap: 0.35rem;
}

.control-group label {
    font-size: 0.75rem;
    font-weight: 500;
    color: var(--text-secondary);
    text-transform: uppercase;
    letter-spacing: 0.06em;
}

.control-group select,
.control-group input {
    height: 42px;
    background: rgba(255, 255, 255, 0.04);
    border: 1px solid var(--border);
    border-radius: var(--radius-sm);
    color: var(--text-primary);
    font-family: var(--font);
    font-size: 0.9rem;
    padding: 0 0.75rem;
    outline: none;
    transition: border-color var(--transition), box-shadow var(--transition);
}

.control-group select:focus,
.control-group input:focus {
    border-color: var(--accent);
    box-shadow: 0 0 0 3px var(--accent-glow);
}

.control-group select option {
    background: #131a2b;
    color: var(--text-primary);
}

.control-btn {
    justify-content: flex-end;
}

.btn-primary {
    height: 42px;
    padding: 0 1.5rem;
    border: none;
    border-radius: var(--radius-sm);
    background: linear-gradient(135deg, var(--accent), #4c6ef5);
    color: #fff;
    font-family: var(--font);
    font-size: 0.9rem;
    font-weight: 600;
    cursor: pointer;
    display: flex;
    align-items: center;
    gap: 0.5rem;
    transition: transform var(--transition), box-shadow var(--transition), opacity var(--transition);
}

.btn-primary:hover {
    transform: translateY(-1px);
    box-shadow: 0 6px 24px rgba(99, 140, 255, 0.35);
}

.btn-primary:active {
    transform: translateY(0);
}

.btn-primary:disabled {
    opacity: 0.5;
    cursor: not-allowed;
    transform: none;
    box-shadow: none;
}

.btn-icon {
    font-size: 0.8rem;
}

.status {
    margin-top: 0.75rem;
    font-size: 0.82rem;
    color: var(--text-secondary);
    min-height: 1.2rem;
    transition: color var(--transition);
}

.status.error {
    color: var(--danger);
}

.status.computing {
    color: var(--warning);
}

.chart-section {
    animation: fadeSlideIn 0.5s ease-out both;
}

@keyframes fadeSlideIn {
    from {
        opacity: 0;
        transform: translateY(16px);
    }

    to {
        opacity: 1;
        transform: translateY(0);
    }
}

.hidden {
    display: none !important;
}

.chart-header {
    display: flex;
    align-items: flex-start;
    justify-content: space-between;
    gap: 1rem;
    margin-bottom: 1rem;
    flex-wrap: wrap;
}

.chart-header h2 {
    font-size: 1.05rem;
    font-weight: 600;
    color: var(--accent-bright);
    letter-spacing: -0.01em;
}

.chart-container {
    width: 100%;
    min-height: 320px;
    border-radius: var(--radius-sm);
    overflow: hidden;
}

.features-panel {
    display: flex;
    flex-wrap: wrap;
    gap: 0.5rem;
    font-size: 0.78rem;
}

.feature-tag {
    background: rgba(99, 140, 255, 0.08);
    border: 1px solid rgba(99, 140, 255, 0.15);
    border-radius: 6px;
    padding: 0.25rem 0.65rem;
    color: var(--text-secondary);
    white-space: nowrap;
    transition: background var(--transition);
}

.feature-tag .val {
    color: var(--accent-bright);
    font-weight: 600;
    margin-left: 0.2rem;
}

.stats-panel {
    display: flex;
    flex-wrap: wrap;
    gap: 0.75rem;
}

.stat-item {
    background: rgba(52, 211, 153, 0.06);
    border: 1px solid rgba(52, 211, 153, 0.15);
    border-radius: 8px;
    padding: 0.4rem 0.85rem;
    text-align: center;
    min-width: 80px;
}

.stat-item .stat-label {
    font-size: 0.65rem;
    color: var(--text-muted);
    text-transform: uppercase;
    letter-spacing: 0.05em;
}

.stat-item .stat-value {
    font-size: 1rem;
    font-weight: 700;
    color: var(--success);
}

.formula-box {
    width: 100%;
    margin-top: 0.75rem;
    background: rgba(99, 140, 255, 0.04);
    border: 1px solid rgba(99, 140, 255, 0.12);
    border-radius: var(--radius-sm);
    padding: 0.85rem 1rem;
}

.formula-title {
    font-size: 0.72rem;
    font-weight: 600;
    color: var(--accent);
    text-transform: uppercase;
    letter-spacing: 0.04em;
    margin-bottom: 0.5rem;
}

.formula-content {
    font-size: 0.82rem;
    color: var(--text-secondary);
    line-height: 1.7;
    word-break: break-all;
    overflow-wrap: break-word;
}

.formula-label {
    color: var(--text-primary);
    font-weight: 500;
}

.formula-terms {
    color: var(--text-secondary);
    font-family: 'Consolas', 'Fira Code', monospace;
    font-size: 0.78rem;
}

.formula-result {
    color: var(--accent-bright);
    font-size: 1rem;
    font-weight: 700;
}

.formula-sim {
    margin-top: 0.4rem;
    font-size: 0.82rem;
    color: var(--text-secondary);
}

.formula-sim strong {
    color: var(--success);
    font-weight: 700;
}

.formula-legend {
    margin-top: 0.35rem;
    font-size: 0.68rem;
    color: var(--text-muted);
    font-style: italic;
}

.btn-window-detail {
    height: 32px;
    padding: 0 1rem;
    border: 1px solid var(--accent);
    border-radius: var(--radius-sm);
    background: rgba(99, 140, 255, 0.08);
    color: var(--accent-bright);
    font-family: var(--font);
    font-size: 0.78rem;
    font-weight: 600;
    cursor: pointer;
    transition: background var(--transition), transform var(--transition);
    margin-left: 0.5rem;
}

.btn-window-detail:hover {
    background: rgba(99, 140, 255, 0.2);
    transform: translateY(-1px);
}

.modal-overlay {
    position: fixed;
    inset: 0;
    background: rgba(0, 0, 0, 0.7);
    backdrop-filter: blur(8px);
    z-index: 1000;
    display: flex;
    align-items: center;
    justify-content: center;
    padding: 1.5rem;
}

.modal-overlay.hidden {
    display: none !important;
}

.modal-container {
    background: var(--bg-primary);
    border: 1px solid var(--border-glow);
    border-radius: var(--radius);
    width: 100%;
    max-width: 1100px;
    max-height: 92vh;
    overflow-y: auto;
    box-shadow: 0 20px 60px rgba(0, 0, 0, 0.6), 0 0 40px rgba(99, 140, 255, 0.08);
}

.modal-header {
    display: flex;
    align-items: center;
    justify-content: space-between;
    padding: 1.2rem 1.5rem;
    border-bottom: 1px solid var(--border);
}

.modal-header h2 {
    font-size: 1.05rem;
    font-weight: 600;
    color: var(--accent-bright);
}

.modal-close {
    width: 36px;
    height: 36px;
    border: 1px solid var(--border);
    border-radius: 50%;
    background: rgba(255, 255, 255, 0.04);
    color: var(--text-secondary);
    font-size: 1.3rem;
    cursor: pointer;
    display: flex;
    align-items: center;
    justify-content: center;
    transition: background var(--transition), color var(--transition);
}

.modal-close:hover {
    background: rgba(248, 113, 113, 0.15);
    color: var(--danger);
}

.modal-body {
    padding: 1.2rem 1.5rem;
    display: flex;
    flex-direction: column;
    gap: 1.2rem;
}

.modal-chart-section {
    border: 1px solid var(--border);
    border-radius: var(--radius-sm);
    padding: 0.85rem;
    background: var(--bg-card);
}

.modal-chart-label {
    display: flex;
    align-items: center;
    gap: 0.75rem;
    margin-bottom: 0.5rem;
    flex-wrap: wrap;
}

.modal-chart-label>span:first-child {
    font-size: 0.85rem;
    font-weight: 600;
    color: var(--accent-bright);
}

.modal-chart {
    width: 100%;
    min-height: 200px;
}

.flip-controls {
    display: flex;
    gap: 0.4rem;
}

.flip-btn {
    padding: 0.2rem 0.6rem;
    border: 1px solid var(--border);
    border-radius: 5px;
    background: rgba(255, 255, 255, 0.03);
    color: var(--text-secondary);
    font-family: var(--font);
    font-size: 0.72rem;
    font-weight: 500;
    cursor: pointer;
    transition: background var(--transition), border-color var(--transition), color var(--transition);
}

.flip-btn:hover {
    background: rgba(99, 140, 255, 0.1);
    border-color: var(--accent);
}

.flip-btn.active {
    background: rgba(99, 140, 255, 0.2);
    border-color: var(--accent);
    color: var(--accent-bright);
}

.transform-badge {
    font-size: 0.68rem;
    color: var(--warning);
    font-style: italic;
}

@media (max-width: 700px) {
    .controls-grid {
        grid-template-columns: 1fr 1fr;
    }

    .main {
        padding: 1rem;
    }

    .modal-container {
        max-height: 95vh;
    }
}