/* ============================================
   CSS Custom Properties
   ============================================ */
:root {
    /* Colors */
    --color-primary: #3182ce;
    --color-primary-hover: #2b6cb0;
    --color-primary-light: #ebf8ff;

    --color-text: #333;
    --color-text-muted: #718096;
    --color-text-heading: #4a5568;
    --color-text-dark: #2d3748;

    --color-bg: linear-gradient(135deg, #f5f7fa 0%, #e4e8ec 100%);
    --color-surface: white;
    --color-surface-alt: #f7fafc;
    --color-border: #e2e8f0;
    --color-border-light: #edf2f7;

    --color-success: #276749;
    --color-success-bg: #c6f6d5;
    --color-danger: #c53030;
    --color-danger-bg: #fed7d7;

    /* Spacing */
    --space-xs: 4px;
    --space-sm: 8px;
    --space-md: 16px;
    --space-lg: 24px;
    --space-xl: 32px;

    /* Border Radius */
    --radius-sm: 4px;
    --radius-md: 6px;
    --radius-lg: 8px;
    --radius-xl: 12px;

    /* Transitions */
    --transition-fast: 0.2s ease;
}

/* ============================================
   Reset & Base
   ============================================ */
* {
    box-sizing: border-box;
    margin: 0;
    padding: 0;
}

body {
    font-family: -apple-system, BlinkMacSystemFont, 'Segoe UI', Roboto, Oxygen, Ubuntu, sans-serif;
    background: var(--color-bg);
    min-height: 100vh;
    color: var(--color-text);
    line-height: 1.6;
}

/* ============================================
   Layout
   ============================================ */
#app {
    max-width: 600px;
    margin: 0 auto;
    padding: var(--space-lg);
}

header {
    text-align: center;
    margin-bottom: var(--space-xl);
}

header h1 {
    font-size: 1.8rem;
    font-weight: 600;
    color: var(--color-text-heading);
}

main {
    background: var(--color-surface);
    border-radius: var(--radius-xl);
    padding: var(--space-xl);
    box-shadow: 0 4px 20px rgba(0, 0, 0, 0.08);
}

/* ============================================
   Buttons
   ============================================ */
.btn {
    padding: 12px var(--space-lg);
    font-size: 1rem;
    border: none;
    border-radius: var(--radius-lg);
    cursor: pointer;
    transition: background var(--transition-fast);
}

.btn-primary {
    background: var(--color-primary);
    color: white;
}

.btn-primary:hover {
    background: var(--color-primary-hover);
}

.btn-secondary {
    background: var(--color-border-light);
    color: var(--color-text-heading);
}

.btn-secondary:hover {
    background: var(--color-border);
}

.btn:disabled,
.navigation button:disabled {
    opacity: 0.4;
    cursor: not-allowed;
}

.btn-lg {
    padding: 14px 40px;
    font-size: 1.1rem;
}

/* ============================================
   Theme Selection
   ============================================ */
.theme-list h2 {
    font-size: 1.2rem;
    color: var(--color-text-muted);
    margin-bottom: var(--space-md);
    font-weight: 500;
}

.theme-list a {
    display: block;
    padding: var(--space-md);
    margin: var(--space-sm) 0;
    color: var(--color-primary);
    text-decoration: none;
    border-radius: var(--radius-lg);
    transition: background var(--transition-fast);
}

.theme-list a:hover {
    background: var(--color-primary-light);
}

/* ============================================
   Intro Page
   ============================================ */
.intro {
    text-align: center;
}

.intro p {
    font-size: 1.1rem;
    color: var(--color-text-heading);
    line-height: 1.8;
    margin-bottom: var(--space-xl);
}

.survey-length-options {
    display: flex;
    flex-direction: column;
    gap: var(--space-xs);
    margin-bottom: var(--space-lg);
    text-align: left;
    max-width: 250px;
    margin-left: auto;
    margin-right: auto;
}

.length-option {
    display: flex;
    align-items: center;
    gap: var(--space-sm);
    padding: var(--space-xs) 0;
    cursor: pointer;
}

.length-option input[type="radio"] {
    cursor: pointer;
}

.length-option span {
    font-size: 0.95rem;
    color: var(--color-text-muted);
}

/* ============================================
   Question View
   ============================================ */
.progress {
    font-size: 0.9rem;
    color: var(--color-text-muted);
    margin-bottom: var(--space-lg);
}

.question-text {
    font-size: 1.3rem;
    color: var(--color-text-dark);
    margin-bottom: var(--space-xl);
    font-style: italic;
}

.answer-buttons {
    display: flex;
    gap: var(--space-md);
    margin-bottom: var(--space-lg);
}

.answer-buttons button {
    flex: 1;
    padding: 14px var(--space-lg);
    font-size: 1rem;
    border: 2px solid var(--color-border);
    border-radius: var(--radius-lg);
    background: var(--color-surface);
    cursor: pointer;
    transition: all var(--transition-fast);
}

.answer-buttons button:hover {
    border-color: var(--color-primary);
    background: var(--color-primary-light);
}

.answer-buttons button.selected {
    border-color: var(--color-primary);
    background: var(--color-primary);
    color: white;
}

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

.navigation button {
    padding: 10px 20px;
    font-size: 0.95rem;
    border: none;
    border-radius: var(--radius-md);
    cursor: pointer;
    transition: all var(--transition-fast);
}

.nav-back {
    background: var(--color-border-light);
    color: var(--color-text-heading);
}

.nav-back:hover:not(:disabled) {
    background: var(--color-border);
}

.nav-next {
    background: var(--color-primary);
    color: white;
}

.nav-next:hover:not(:disabled) {
    background: var(--color-primary-hover);
}

/* ============================================
   Results View
   ============================================ */
.results {
    text-align: center;
}

.results h2 {
    font-size: 1.2rem;
    color: var(--color-text-muted);
    font-weight: 500;
    margin-bottom: var(--space-sm);
}

.score {
    font-size: 3rem;
    font-weight: 700;
    color: var(--color-primary);
    margin: var(--space-md) 0 var(--space-lg);
}

.score-detail {
    font-size: 1.5rem;
    color: var(--color-text-muted);
    margin-bottom: var(--space-lg);
}

.results button {
    margin-top: var(--space-xl);
}

/* Category Ratings */
.category-ratings {
    margin: var(--space-lg) 0;
    text-align: left;
}

.category-rating {
    display: flex;
    justify-content: space-between;
    align-items: center;
    padding: var(--space-md);
    margin: var(--space-sm) 0;
    background: var(--color-surface-alt);
    border-radius: var(--radius-lg);
}

.category-name {
    font-weight: 500;
    color: var(--color-text-dark);
}

.rating {
    font-weight: 700;
    font-size: 0.9rem;
    padding: var(--space-xs) var(--space-md);
    border-radius: var(--radius-sm);
    background: var(--color-surface-alt);
    color: var(--color-text-dark);
}

.rating.high {
    background: var(--color-success-bg);
    color: var(--color-success);
}

.rating.low {
    background: var(--color-danger-bg);
    color: var(--color-danger);
}