:root[data-theme="dark"] {
    --bg-color: #111111;
    --text-color: #ffffff;
    --text-secondary: #aaa;
    --accent-color: #4FC3F7;
    --secondary-bg: #1E1E1E;
    --input-bg: #2A2A2A;
    --border-color: #333;
    --success-color: #00C853;
}

:root[data-theme="light"] {
    --bg-color: #ffffff;
    --text-color: #1a1a1a;
    --text-secondary: #666;
    --accent-color: #006BA6;
    --secondary-bg: #f5f5f5;
    --input-bg: #ffffff;
    --border-color: #e0e0e0;
    --success-color: #10b981;
}

* {
    box-sizing: border-box;
    margin: 0;
    padding: 0;
    -webkit-tap-highlight-color: transparent;
}

body {
    background-color: var(--bg-color);
    color: var(--text-color);
    font-family: 'Inter', -apple-system, BlinkMacSystemFont, sans-serif;
    overflow-x: hidden;
    min-height: 100vh;
    transition: background-color 0.3s ease, color 0.3s ease;
}

/* Theme Toggle */
.theme-toggle {
    position: fixed;
    top: 20px;
    right: 20px;
    z-index: 200;
    background: var(--secondary-bg);
    border: 1px solid var(--border-color);
    border-radius: 20px;
    padding: 8px 16px;
    cursor: pointer;
    font-size: 14px;
    color: var(--text-color);
    transition: all 0.2s ease;
}

.theme-toggle:hover {
    transform: scale(1.05);
}

/* Progress Bar */
.progress-container {
    position: fixed;
    top: 0;
    left: 0;
    width: 100%;
    height: 6px;
    background: var(--secondary-bg);
    z-index: 100;
    box-shadow: 0 2px 4px rgba(0, 0, 0, 0.1);
}

.progress-bar {
    height: 100%;
    background: var(--accent-color);
    width: 0%;
    transition: width 0.3s ease;
    box-shadow: 0 0 20px var(--accent-color), 0 0 40px var(--accent-color);
}

.progress-text {
    position: fixed;
    top: 15px;
    left: 20px;
    font-size: 12px;
    color: var(--text-secondary);
    z-index: 101;
}

/* Main Container */
.container {
    max-width: 700px;
    margin: 0 auto;
    padding: 80px 20px 180px;
    min-height: 100vh;
}

/* Slides */
.slide {
    display: none;
    animation: fadeIn 0.4s ease;
}

.slide.active {
    display: block;
}

@keyframes fadeIn {
    from {
        opacity: 0;
        transform: translateY(20px);
    }

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

/* Typography */
h1 {
    font-size: 32px;
    font-weight: 700;
    margin-bottom: 16px;
    line-height: 1.2;
    background: linear-gradient(135deg, var(--accent-color), #4FC3F7);
    -webkit-background-clip: text;
    background-clip: text;
    -webkit-text-fill-color: transparent;
}

h2 {
    font-size: 24px;
    font-weight: 600;
    margin-bottom: 32px;
    line-height: 1.4;
    color: var(--text-color);
    white-space: pre-line;
}

p {
    font-size: 16px;
    color: var(--text-secondary);
    margin-bottom: 32px;
    line-height: 1.6;
    white-space: pre-line;
}

/* Options Grid */
.options-grid {
    display: flex;
    flex-direction: column;
    gap: 12px;
    margin-bottom: 24px;
}

.option-btn {
    background: var(--secondary-bg);
    border: 2px solid var(--border-color);
    color: var(--text-color);
    padding: 18px 20px;
    border-radius: 12px;
    font-size: 16px;
    text-align: left;
    cursor: pointer;
    transition: all 0.2s ease;
    position: relative;
    width: 100%;
}

.option-btn:hover {
    border-color: var(--accent-color);
    transform: translateX(4px);
}

.option-btn.selected {
    background: var(--accent-color);
    border-color: var(--accent-color);
    color: #fff;
}

.option-btn.selected::before {
    content: "✓";
    position: absolute;
    right: 20px;
    font-weight: bold;
}

/* Other Option */
.other-option {
    margin-top: 8px;
}

.other-input {
    width: 100%;
    background: var(--input-bg);
    border: 2px solid var(--border-color);
    color: var(--text-color);
    font-size: 16px;
    padding: 12px 16px;
    border-radius: 8px;
    font-family: inherit;
    margin-top: 8px;
    transition: border-color 0.3s ease;
}

.other-input:focus {
    outline: none;
    border-color: var(--accent-color);
}

/* Text Inputs */
textarea,
input[type="text"],
input[type="email"] {
    width: 100%;
    background: var(--input-bg);
    border: 2px solid var(--border-color);
    color: var(--text-color);
    font-size: 18px;
    padding: 16px;
    font-family: inherit;
    resize: vertical;
    border-radius: 12px;
    transition: border-color 0.3s ease;
    min-height: 120px;
}

input[type="email"] {
    min-height: auto;
}

textarea:focus,
input:focus {
    outline: none;
    border-color: var(--accent-color);
}

/* Navigation */
.nav-container {
    position: fixed;
    bottom: 0;
    left: 0;
    right: 0;
    background: var(--bg-color);
    border-top: 1px solid var(--border-color);
    padding: 20px;
    z-index: 100;
    box-shadow: 0 -4px 12px rgba(0, 0, 0, 0.05);
}

.nav-buttons {
    max-width: 700px;
    margin: 0 auto;
    display: flex;
    gap: 12px;
    align-items: center;
}

.nav-btn {
    background: var(--secondary-bg);
    color: var(--text-color);
    border: 2px solid var(--border-color);
    padding: 14px 24px;
    border-radius: 12px;
    font-size: 16px;
    font-weight: 600;
    cursor: pointer;
    transition: all 0.2s ease;
    flex: 0 0 auto;
}

.nav-btn:disabled {
    opacity: 0.4;
    cursor: not-allowed;
}

.nav-btn:not(:disabled):hover {
    transform: translateY(-2px);
    box-shadow: 0 4px 12px rgba(0, 0, 0, 0.1);
}

.nav-btn-next {
    background: var(--accent-color);
    color: white;
    border-color: var(--accent-color);
    flex: 1;
    font-size: 18px;
}

.nav-btn-next:not(:disabled):hover {
    opacity: 0.9;
}

/* Intro/Outro */
.intro-content {
    text-align: center;
    padding: 40px 0;
}

.start-btn {
    background: var(--accent-color);
    color: white;
    border: none;
    padding: 18px 48px;
    border-radius: 30px;
    font-size: 18px;
    font-weight: 600;
    cursor: pointer;
    margin-top: 20px;
    box-shadow: 0 4px 20px var(--accent-color);
    transition: all 0.3s ease;
}

.start-btn:hover {
    transform: translateY(-2px);
    box-shadow: 0 6px 25px var(--accent-color);
}

.start-btn:disabled {
    opacity: 0.5;
    cursor: not-allowed;
}

/* User ID Input */
.user-id-container {
    margin: 30px 0 20px;
}

.user-id-label {
    font-size: 14px;
    color: var(--text-secondary);
    margin-bottom: 12px;
    line-height: 1.5;
}

.user-id-input {
    width: 120px;
    background: var(--input-bg);
    border: 2px solid var(--border-color);
    color: var(--text-color);
    font-size: 24px;
    font-weight: 600;
    padding: 12px;
    text-align: center;
    border-radius: 12px;
    font-family: 'Courier New', monospace;
    letter-spacing: 8px;
    transition: border-color 0.3s ease;
}

.user-id-input:focus {
    outline: none;
    border-color: var(--accent-color);
    box-shadow: 0 0 0 3px rgba(0, 107, 166, 0.1);
}

.user-id-input.error {
    border-color: #ff4444;
}

.user-id-error {
    color: #ff4444;
    font-size: 12px;
    margin-top: 8px;
    display: none;
}

/* Interview Contact Fields */
.interview-contacts {
    margin-top: 24px;
    padding: 20px;
    background: var(--secondary-bg);
    border-radius: 12px;
    border: 2px solid var(--border-color);
    display: none;
}

.interview-contacts.show {
    display: block;
    animation: fadeIn 0.3s ease;
}

.interview-contacts h3 {
    font-size: 16px;
    margin-bottom: 16px;
    color: var(--text-color);
}

.contact-field {
    margin-bottom: 16px;
}

.contact-field label {
    display: block;
    font-size: 14px;
    color: var(--text-secondary);
    margin-bottom: 8px;
}

.contact-field input {
    width: 100%;
    background: var(--input-bg);
    border: 2px solid var(--border-color);
    color: var(--text-color);
    font-size: 16px;
    padding: 12px;
    border-radius: 8px;
    font-family: inherit;
    transition: border-color 0.3s ease;
}

.contact-field input:focus {
    outline: none;
    border-color: var(--accent-color);
}

/* Feedback section on outro */
.feedback-section {
    margin-top: 40px;
    text-align: left;
}

.feedback-section h3 {
    font-size: 18px;
    margin-bottom: 12px;
    color: var(--text-color);
}

.feedback-section p {
    font-size: 14px;
    margin-bottom: 16px;
}

/* Multiple choice hint */
.multiple-hint {
    font-size: 13px;
    color: var(--text-secondary);
    margin-bottom: 16px;
    font-style: italic;
}

/* Responsive */
@media (max-width: 600px) {
    h1 {
        font-size: 26px;
    }

    h2 {
        font-size: 20px;
    }

    .container {
        padding: 60px 16px 160px;
    }
}