:root {
    --primary-color: #6366f1;
    --primary-dark: #4f46e5;
    --secondary-color: #8b5cf6;
    --success-color: #10b981;
    --danger-color: #ef4444;
    --warning-color: #f59e0b;
    --info-color: #3b82f6;
    --light-bg: #f8fafc;
    --card-bg: #ffffff;
    --text-primary: #1e293b;
    --text-secondary: #64748b;
    --border-color: #e2e8f0;
    --shadow-sm: 0 1px 2px 0 rgba(0, 0, 0, 0.05);
    --shadow-md: 0 4px 6px -1px rgba(0, 0, 0, 0.1);
    --shadow-lg: 0 10px 15px -3px rgba(0, 0, 0, 0.1);
    --radius-sm: 0.5rem;
    --radius-md: 0.75rem;
    --radius-lg: 1rem;
    --transition-fast: 150ms ease;
    --transition-normal: 250ms ease;
}

* {
    box-sizing: border-box;
}

body {
    margin: 0;
    padding: 0;
    background: linear-gradient(135deg, #667eea 0%, #764ba2 100%);
    background-attachment: fixed;
    font-family: -apple-system, BlinkMacSystemFont, "Segoe UI", Roboto, "Helvetica Neue", Arial, sans-serif;
    color: var(--text-primary);
    min-height: 100vh;
}

/* Progress Bar */
.progress-bar-container {
    position: fixed;
    top: 0;
    left: 0;
    right: 0;
    height: 4px;
    background: rgba(255, 255, 255, 0.2);
    z-index: 1050;
    backdrop-filter: blur(10px);
}

.progress-bar-fill {
    height: 100%;
    background: linear-gradient(90deg, var(--success-color), var(--primary-color));
    width: 0%;
    transition: width var(--transition-normal);
}

/* Layout */
.layout-container {
    display: flex;
    min-height: 100vh;
    padding-top: 4px;
}

/* Desktop Side Panel */
.side-panel {
    position: fixed;
    left: 0;
    top: 4px;
    bottom: 0;
    width: 380px;
    background: var(--card-bg);
    box-shadow: var(--shadow-lg);
    padding: 2rem 1.5rem;
    display: flex;
    flex-direction: column;
    overflow-y: auto;
    z-index: 1000;
}

.side-panel-header {
    margin-bottom: 1.5rem;
}

.side-panel-header h5 {
    font-size: 1.5rem;
    font-weight: 700;
    color: var(--text-primary);
    margin: 0 0 0.5rem 0;
    display: flex;
    align-items: center;
    gap: 0.5rem;
}

.side-panel-header .subtitle {
    font-size: 0.875rem;
    color: var(--text-secondary);
}

.results-list {
    flex: 1;
    padding: 1.25rem;
    background: linear-gradient(135deg, #f0f9ff 0%, #e0e7ff 100%);
    border-radius: var(--radius-md);
    border: 2px solid var(--border-color);
    font-weight: 600;
    color: var(--primary-color);
    min-height: 6rem;
    line-height: 1.8;
    overflow-y: auto;
    margin-bottom: 1.5rem;
    transition: all var(--transition-normal);
}

.results-list:empty::after {
    content: attr(data-placeholder);
    color: var(--text-secondary);
    font-weight: 400;
    font-style: italic;
}

.reset-btn {
    width: 100%;
    padding: 0.875rem;
    background: linear-gradient(135deg, var(--danger-color), #dc2626);
    border: none;
    color: white;
    font-weight: 600;
    border-radius: var(--radius-md);
    cursor: pointer;
    transition: all var(--transition-fast);
    display: flex;
    align-items: center;
    justify-content: center;
    gap: 0.5rem;
}

.reset-btn:hover {
    transform: translateY(-2px);
    box-shadow: var(--shadow-md);
}

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

/* Main Content */
.main-content {
    flex: 1;
    margin-left: 380px;
    padding: 2rem;
}

.container {
    max-width: 900px;
    margin: 0 auto;
}

/* Header */
.header-section {
    text-align: center;
    margin-bottom: 2.5rem;
    background: var(--card-bg);
    padding: 2.5rem 2rem;
    border-radius: var(--radius-lg);
    box-shadow: var(--shadow-lg);
}

.header-section h1 {
    font-size: 2.5rem;
    font-weight: 800;
    background: linear-gradient(135deg, var(--primary-color), var(--secondary-color));
    -webkit-background-clip: text;
    -webkit-text-fill-color: transparent;
    background-clip: text;
    margin-bottom: 1rem;
}

.header-section .lead {
    color: var(--text-secondary);
    font-size: 1.125rem;
    margin: 0;
}

/* Instructions Card */
.instructions-card {
    background: var(--card-bg);
    padding: 2rem;
    border-radius: var(--radius-lg);
    box-shadow: var(--shadow-md);
    margin-bottom: 2rem;
}

.instructions-card h5 {
    font-weight: 700;
    color: var(--text-primary);
    margin-bottom: 1rem;
    display: flex;
    align-items: center;
    gap: 0.5rem;
}

.instructions-card ul {
    margin: 1rem 0;
    padding-left: 1.5rem;
}

.instructions-card li {
    margin-bottom: 0.5rem;
    color: var(--text-secondary);
}

/* Color Legend */
.color-legend {
    margin-top: 1.5rem;
    padding-top: 1.5rem;
    border-top: 1px solid var(--border-color);
}

.legend-title {
    font-weight: 600;
    margin-bottom: 0.75rem;
    color: var(--text-primary);
}

.legend-item {
    display: flex;
    align-items: center;
    margin-bottom: 0.5rem;
    font-size: 0.875rem;
    color: var(--text-secondary);
}

.legend-dot {
    width: 16px;
    height: 16px;
    border-radius: 50%;
    margin-right: 0.75rem;
    flex-shrink: 0;
}

/* Question Cards */
.question-section {
    background: var(--card-bg);
    padding: 1.75rem;
    border-radius: var(--radius-lg);
    box-shadow: var(--shadow-md);
    margin-bottom: 1.5rem;
    position: relative;
    overflow: hidden;
    transition: all var(--transition-normal);
}

.question-section:hover {
    box-shadow: var(--shadow-lg);
    transform: translateY(-2px);
}

.question-color-bar {
    position: absolute;
    left: 0;
    top: 0;
    bottom: 0;
    width: 6px;
}

.question-section h6 {
    font-weight: 700;
    color: var(--text-primary);
    margin-bottom: 1.25rem;
    padding-left: 1rem;
}

/* Radio Options */
.form-check {
    margin-bottom: 0.875rem;
    padding-left: 2.25rem;
}

.form-check-input {
    width: 1.25rem;
    height: 1.25rem;
    margin-top: 0.125rem;
    cursor: pointer;
    border: 2px solid var(--border-color);
}

.form-check-input:checked {
    background-color: var(--primary-color);
    border-color: var(--primary-color);
}

.form-check-input:focus {
    border-color: var(--primary-color);
    box-shadow: 0 0 0 0.25rem rgba(99, 102, 241, 0.15);
}

.form-check-label {
    font-weight: 500;
    color: var(--text-primary);
    cursor: pointer;
    user-select: none;
}

.answer-subset {
    display: block;
    font-size: 0.875rem;
    color: var(--text-secondary);
    margin-top: 0.25rem;
    margin-left: 0.25rem;
}

/* Default Answer Styling */
.default-answer {
    color: var(--text-secondary) !important;
    font-style: italic;
}

.default-radio .form-check-input {
    border-color: var(--text-secondary) !important;
    background-color: var(--light-bg) !important;
}

.default-radio .form-check-input:checked {
    background-color: var(--text-secondary) !important;
}

/* Footer */
footer {
    text-align: center;
    padding: 2rem 1rem;
    color: rgba(255, 255, 255, 0.8);
    font-size: 0.875rem;
}

/* Mobile Bottom Sheet */
.mobile-bottom-sheet {
    display: none;
}

/* Tablet & Mobile Responsive */
@media (max-width: 991px) {
    body {
        padding-bottom: 0;
    }

    .side-panel {
        display: none;
    }

    .main-content {
        margin-left: 0;
        padding: 1.5rem 1rem;
        padding-bottom: 180px;
    }

    .header-section {
        padding: 2rem 1.5rem;
    }

    .header-section h1 {
        font-size: 2rem;
    }

    .instructions-card {
        padding: 1.5rem;
    }

    .question-section {
        padding: 1.5rem;
    }

    .question-color-bar {
        width: 4px;
    }

    /* Mobile Bottom Sheet */
    .mobile-bottom-sheet {
        display: block;
        position: fixed;
        bottom: 0;
        left: 0;
        right: 0;
        background: var(--card-bg);
        box-shadow: 0 -4px 20px rgba(0, 0, 0, 0.15);
        z-index: 1040;
        transition: transform var(--transition-normal);
    }

    .mobile-bottom-sheet.collapsed {
        transform: translateY(calc(100% - 80px));
    }

    .bottom-sheet-handle {
        padding: 0.75rem 1rem;
        background: linear-gradient(135deg, var(--primary-color), var(--secondary-color));
        color: white;
        cursor: pointer;
        display: flex;
        align-items: center;
        justify-content: space-between;
        user-select: none;
    }

    .bottom-sheet-handle-bar {
        width: 48px;
        height: 4px;
        background: rgba(255, 255, 255, 0.5);
        border-radius: 2px;
        position: absolute;
        top: 0.5rem;
        left: 50%;
        transform: translateX(-50%);
    }

    .bottom-sheet-title {
        font-weight: 700;
        font-size: 1rem;
        display: flex;
        align-items: center;
        gap: 0.5rem;
        padding-top: 0.5rem;
    }

    .bottom-sheet-toggle {
        background: none;
        border: none;
        color: white;
        font-size: 1.5rem;
        cursor: pointer;
        padding: 0;
        line-height: 1;
        transition: transform var(--transition-fast);
    }

    .mobile-bottom-sheet.collapsed .bottom-sheet-toggle {
        transform: rotate(180deg);
    }

    .bottom-sheet-content {
        padding: 1.25rem;
        max-height: 50vh;
        overflow-y: auto;
    }

    .bottom-sheet-results {
        padding: 1rem;
        background: linear-gradient(135deg, #f0f9ff 0%, #e0e7ff 100%);
        border-radius: var(--radius-md);
        font-weight: 600;
        color: var(--primary-color);
        min-height: 4rem;
        line-height: 1.6;
        margin-bottom: 1rem;
    }

    .bottom-sheet-results:empty::after {
        content: attr(data-placeholder);
        color: var(--text-secondary);
        font-weight: 400;
        font-style: italic;
    }

    .mobile-reset-btn {
        width: 100%;
        padding: 0.875rem;
        background: linear-gradient(135deg, var(--danger-color), #dc2626);
        border: none;
        color: white;
        font-weight: 600;
        border-radius: var(--radius-md);
        cursor: pointer;
        display: flex;
        align-items: center;
        justify-content: center;
        gap: 0.5rem;
    }

    footer {
        padding-bottom: 100px;
    }
}

/* Small Mobile */
@media (max-width: 576px) {
    .main-content {
        padding: 1rem 0.75rem;
    }

    .header-section {
        padding: 1.5rem 1rem;
        margin-bottom: 1.5rem;
    }

    .header-section h1 {
        font-size: 1.75rem;
    }

    .header-section .lead {
        font-size: 1rem;
    }

    .instructions-card {
        padding: 1.25rem;
    }

    .question-section {
        padding: 1.25rem;
    }
}

/* Smooth Scrolling */
html {
    scroll-behavior: smooth;
}

/* Custom Scrollbar */
::-webkit-scrollbar {
    width: 8px;
    height: 8px;
}

::-webkit-scrollbar-track {
    background: var(--light-bg);
}

::-webkit-scrollbar-thumb {
    background: var(--text-secondary);
    border-radius: 4px;
}

::-webkit-scrollbar-thumb:hover {
    background: var(--text-primary);
}