/* ===== CSS Variables ===== */
:root {
    --black: #000000;
    --white: #ffffff;
    --gray-50: #fafafa;
    --gray-100: #f5f5f5;
    --gray-200: #e5e5e5;
    --gray-300: #d4d4d4;
    --gray-400: #a3a3a3;
    --gray-500: #737373;
    --gray-600: #525252;
    --gray-700: #404040;
    --gray-800: #262626;
    --gray-900: #171717;
    --gray-950: #0a0a0a;
    
    --font-family: 'Inter', -apple-system, BlinkMacSystemFont, sans-serif;
    --transition-fast: 0.15s ease;
    --transition-normal: 0.3s ease;
    --transition-slow: 0.5s ease;
    --border-radius: 12px;
    --border-radius-lg: 20px;
}

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

html {
    font-size: 16px;
    scroll-behavior: smooth;
}

body {
    font-family: var(--font-family);
    background: var(--gray-950);
    color: var(--white);
    min-height: 100vh;
    line-height: 1.6;
    -webkit-font-smoothing: antialiased;
    -moz-osx-font-smoothing: grayscale;
}

/* ===== Screen Management ===== */
.screen {
    display: none;
    min-height: 100vh;
    opacity: 0;
    transition: opacity var(--transition-normal);
}

.screen.active {
    display: flex;
    flex-direction: column;
    opacity: 1;
}

.container {
    max-width: 600px;
    width: 100%;
    margin: 0 auto;
    padding: 2rem;
    display: flex;
    flex-direction: column;
    align-items: center;
    justify-content: center;
    min-height: 100vh;
    text-align: center;
}

/* ===== Landing Screen ===== */
#landing .logo {
    font-size: 1rem;
    font-weight: 600;
    letter-spacing: 0.3em;
    color: var(--gray-400);
    margin-bottom: 1rem;
    text-transform: uppercase;
}

#landing .title {
    font-size: clamp(2.5rem, 8vw, 4rem);
    font-weight: 700;
    letter-spacing: -0.02em;
    margin-bottom: 0.5rem;
    background: linear-gradient(180deg, var(--white) 0%, var(--gray-400) 100%);
    -webkit-background-clip: text;
    -webkit-text-fill-color: transparent;
    background-clip: text;
}

#landing .subtitle {
    font-size: 1.1rem;
    color: var(--gray-400);
    margin-bottom: 3rem;
    font-weight: 300;
}

/* Stats Preview */
.stats-preview {
    display: flex;
    align-items: center;
    gap: 2rem;
    padding: 1.5rem 2rem;
    background: var(--gray-900);
    border: 1px solid var(--gray-800);
    border-radius: var(--border-radius-lg);
    margin-bottom: 2rem;
}

.stat-item {
    display: flex;
    flex-direction: column;
    align-items: center;
    gap: 0.25rem;
}

.stat-label {
    font-size: 0.75rem;
    color: var(--gray-500);
    text-transform: uppercase;
    letter-spacing: 0.1em;
}

.stat-value {
    font-size: 1.5rem;
    font-weight: 600;
    color: var(--white);
}

.stat-divider {
    width: 1px;
    height: 40px;
    background: var(--gray-800);
}

/* Loading Status */
.loading-status {
    display: flex;
    align-items: center;
    gap: 0.75rem;
    color: var(--gray-400);
    font-size: 0.9rem;
    margin-bottom: 1.5rem;
}

.spinner {
    width: 20px;
    height: 20px;
    border: 2px solid var(--gray-800);
    border-top-color: var(--white);
    border-radius: 50%;
    animation: spin 1s linear infinite;
}

@keyframes spin {
    to { transform: rotate(360deg); }
}

.question-count {
    color: var(--gray-400);
    font-size: 0.9rem;
    margin-bottom: 2rem;
}

.question-count span {
    color: var(--white);
    font-weight: 600;
}

/* ===== Buttons ===== */
.btn {
    display: inline-flex;
    align-items: center;
    justify-content: center;
    gap: 0.5rem;
    padding: 1rem 2rem;
    font-family: inherit;
    font-size: 1rem;
    font-weight: 500;
    border: none;
    border-radius: var(--border-radius);
    cursor: pointer;
    transition: all var(--transition-fast);
    text-decoration: none;
}

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

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

.btn-primary:hover:not(:disabled) {
    background: var(--gray-200);
    transform: translateY(-2px);
}

.btn-primary:active:not(:disabled) {
    transform: translateY(0);
}

.btn-secondary {
    background: transparent;
    color: var(--gray-400);
    border: 1px solid var(--gray-800);
    margin-top: 1rem;
}

.btn-secondary:hover:not(:disabled) {
    color: var(--white);
    border-color: var(--gray-600);
}

.btn-outline {
    background: transparent;
    color: var(--gray-400);
    border: 1px solid var(--gray-700);
}

.btn-outline:hover:not(:disabled) {
    color: var(--white);
    border-color: var(--gray-500);
}

/* ===== Quiz Screen ===== */
#quiz {
    background: var(--gray-950);
}

.quiz-header {
    display: flex;
    align-items: center;
    justify-content: space-between;
    padding: 1.5rem 2rem;
    background: var(--gray-900);
    border-bottom: 1px solid var(--gray-800);
    position: sticky;
    top: 0;
    z-index: 100;
}

.round-info {
    display: flex;
    align-items: baseline;
    gap: 0.25rem;
}

.round-label {
    font-size: 0.75rem;
    color: var(--gray-500);
    text-transform: uppercase;
    letter-spacing: 0.1em;
    margin-right: 0.5rem;
}

.round-number {
    font-size: 1.5rem;
    font-weight: 700;
    color: var(--white);
}

.round-total {
    font-size: 1rem;
    color: var(--gray-500);
}

.progress-container {
    flex: 1;
    max-width: 300px;
    margin: 0 2rem;
    position: relative;
}

.progress-bar {
    height: 4px;
    background: var(--gray-800);
    border-radius: 2px;
    overflow: hidden;
    position: relative;
}

.progress-bar::after {
    content: '';
    position: absolute;
    left: 0;
    top: 0;
    height: 100%;
    width: var(--progress, 0%);
    background: var(--white);
    border-radius: 2px;
    transition: width var(--transition-normal);
}

.progress-text {
    font-size: 0.8rem;
    color: var(--gray-400);
    text-align: center;
    display: block;
    margin-top: 0.5rem;
}

.score-info {
    display: flex;
    align-items: baseline;
    gap: 0.5rem;
}

.score-label {
    font-size: 0.75rem;
    color: var(--gray-500);
    text-transform: uppercase;
    letter-spacing: 0.1em;
}

.score-value {
    font-size: 1.5rem;
    font-weight: 700;
    color: var(--white);
}

/* Timer Info */
.timer-info {
    display: flex;
    align-items: baseline;
    gap: 0.5rem;
    margin-right: 1rem;
}

.timer-label {
    font-size: 0.75rem;
    color: var(--gray-500);
    text-transform: uppercase;
    letter-spacing: 0.1em;
}

.timer-value {
    font-size: 1.25rem;
    font-weight: 600;
    color: var(--white);
    font-variant-numeric: tabular-nums;
}

/* Question Header with Timer */
.question-header {
    display: flex;
    justify-content: space-between;
    align-items: center;
    margin-bottom: 1rem;
}

.question-header .question-number {
    margin-bottom: 0;
}

.question-timer {
    display: flex;
    align-items: center;
    gap: 0.4rem;
    color: var(--gray-400);
    font-size: 0.9rem;
    font-weight: 500;
    padding: 0.35rem 0.75rem;
    background: var(--gray-800);
    border-radius: 20px;
}

.question-timer svg {
    opacity: 0.7;
}

.question-timer.warning {
    color: #fbbf24;
}

.question-timer.danger {
    color: #ef4444;
}

/* Results Time */
.results-time {
    display: flex;
    align-items: center;
    justify-content: center;
    gap: 0.5rem;
    color: var(--gray-400);
    font-size: 1.1rem;
    margin-top: 0.5rem;
}

.results-time svg {
    opacity: 0.7;
}

/* Quiz Main */
.quiz-main {
    flex: 1;
    display: flex;
    flex-direction: column;
    max-width: 800px;
    width: 100%;
    margin: 0 auto;
    padding: 2rem;
}

.question-card {
    background: var(--gray-900);
    border: 1px solid var(--gray-800);
    border-radius: var(--border-radius-lg);
    padding: 2rem;
    margin-bottom: 2rem;
}

.question-number {
    font-size: 0.8rem;
    color: var(--gray-500);
    text-transform: uppercase;
    letter-spacing: 0.1em;
    margin-bottom: 1rem;
}

.question-text {
    font-size: 1.25rem;
    font-weight: 500;
    line-height: 1.7;
    color: var(--white);
}

/* Options */
.options-container {
    display: flex;
    flex-direction: column;
    gap: 1rem;
    margin-bottom: 2rem;
}

.option {
    display: flex;
    align-items: flex-start;
    gap: 1rem;
    padding: 1.25rem 1.5rem;
    background: var(--gray-900);
    border: 1px solid var(--gray-800);
    border-radius: var(--border-radius);
    cursor: pointer;
    transition: all var(--transition-fast);
}

.option:hover {
    border-color: var(--gray-600);
    background: var(--gray-800);
}

.option.selected {
    border-color: var(--white);
    background: var(--gray-800);
}

.option.correct {
    border-color: var(--white);
    background: rgba(255, 255, 255, 0.1);
}

.option.incorrect {
    border-color: var(--gray-600);
    opacity: 0.6;
}

.option-letter {
    display: flex;
    align-items: center;
    justify-content: center;
    width: 32px;
    height: 32px;
    background: var(--gray-800);
    border-radius: 8px;
    font-size: 0.9rem;
    font-weight: 600;
    color: var(--gray-400);
    flex-shrink: 0;
    transition: all var(--transition-fast);
}

.option.selected .option-letter {
    background: var(--white);
    color: var(--black);
}

.option.correct .option-letter {
    background: var(--white);
    color: var(--black);
}

.option-text {
    font-size: 1rem;
    color: var(--gray-300);
    line-height: 1.5;
    padding-top: 0.25rem;
}

.option.selected .option-text,
.option.correct .option-text {
    color: var(--white);
}

.quiz-actions {
    display: flex;
    justify-content: flex-end;
}

/* Quiz Footer */
.quiz-footer {
    padding: 1.5rem 2rem;
    background: var(--gray-900);
    border-top: 1px solid var(--gray-800);
}

.accuracy-tracker {
    display: flex;
    align-items: center;
    justify-content: center;
    gap: 2rem;
}

.accuracy-item {
    display: flex;
    flex-direction: column;
    align-items: center;
    gap: 0.25rem;
}

.accuracy-label {
    font-size: 0.7rem;
    color: var(--gray-500);
    text-transform: uppercase;
    letter-spacing: 0.1em;
}

.accuracy-value {
    font-size: 1.25rem;
    font-weight: 600;
    color: var(--gray-400);
}

.accuracy-item.current .accuracy-value {
    color: var(--white);
}

.accuracy-arrow {
    color: var(--gray-600);
    font-size: 1.25rem;
}

/* ===== Round Complete Screen ===== */
.round-complete-icon {
    width: 80px;
    height: 80px;
    display: flex;
    align-items: center;
    justify-content: center;
    background: var(--white);
    color: var(--black);
    font-size: 2rem;
    font-weight: 700;
    border-radius: 50%;
    margin-bottom: 2rem;
}

.round-complete-title {
    font-size: 2rem;
    font-weight: 700;
    margin-bottom: 2rem;
}

.round-stats {
    display: flex;
    gap: 3rem;
    margin-bottom: 3rem;
}

.round-stat {
    display: flex;
    flex-direction: column;
    align-items: center;
    gap: 0.5rem;
}

.round-stat-value {
    font-size: 3rem;
    font-weight: 700;
    color: var(--white);
}

.round-stat-label {
    font-size: 0.9rem;
    color: var(--gray-500);
    text-transform: uppercase;
    letter-spacing: 0.1em;
}

/* ===== Results Screen ===== */
.results-title {
    font-size: 2.5rem;
    font-weight: 700;
    margin-bottom: 2rem;
    background: linear-gradient(180deg, var(--white) 0%, var(--gray-400) 100%);
    -webkit-background-clip: text;
    -webkit-text-fill-color: transparent;
    background-clip: text;
}

.results-summary {
    text-align: center;
    margin-bottom: 3rem;
}

.results-main {
    display: flex;
    align-items: baseline;
    justify-content: center;
    gap: 0.25rem;
    margin-bottom: 0.5rem;
}

.results-score {
    font-size: 5rem;
    font-weight: 700;
    color: var(--white);
}

.results-total {
    font-size: 2rem;
    color: var(--gray-500);
}

.results-accuracy {
    font-size: 1.5rem;
    color: var(--gray-400);
}

.results-breakdown {
    width: 100%;
    background: var(--gray-900);
    border: 1px solid var(--gray-800);
    border-radius: var(--border-radius-lg);
    padding: 1.5rem;
    margin-bottom: 2rem;
}

.results-breakdown h3 {
    font-size: 0.8rem;
    color: var(--gray-500);
    text-transform: uppercase;
    letter-spacing: 0.1em;
    margin-bottom: 1rem;
    text-align: left;
}

.breakdown-list {
    display: flex;
    flex-direction: column;
    gap: 0.75rem;
}

.breakdown-item {
    display: flex;
    align-items: center;
    justify-content: space-between;
    padding: 1rem;
    background: var(--gray-800);
    border-radius: var(--border-radius);
}

.breakdown-round {
    font-weight: 500;
    color: var(--white);
}

.breakdown-score {
    color: var(--gray-400);
}

.results-comparison {
    display: flex;
    align-items: center;
    justify-content: center;
    gap: 2rem;
    margin-bottom: 3rem;
    padding: 1.5rem;
    background: var(--gray-900);
    border: 1px solid var(--gray-800);
    border-radius: var(--border-radius-lg);
}

.comparison-item {
    display: flex;
    flex-direction: column;
    align-items: center;
    gap: 0.25rem;
}

.comparison-label {
    font-size: 0.75rem;
    color: var(--gray-500);
    text-transform: uppercase;
    letter-spacing: 0.1em;
}

.comparison-value {
    font-size: 1.5rem;
    font-weight: 600;
    color: var(--white);
}

.comparison-vs {
    color: var(--gray-600);
    font-size: 1rem;
}

.results-actions {
    display: flex;
    gap: 1rem;
}

/* ===== Responsive Design ===== */
@media (max-width: 768px) {
    .quiz-header {
        flex-wrap: wrap;
        gap: 1rem;
        padding: 1rem;
    }

    .progress-container {
        order: 3;
        max-width: 100%;
        margin: 0;
        width: 100%;
    }

    .quiz-main {
        padding: 1.5rem;
    }

    .question-card {
        padding: 1.5rem;
    }

    .stats-preview {
        flex-direction: column;
        gap: 1rem;
        padding: 1.5rem;
    }

    .stat-divider {
        width: 60px;
        height: 1px;
    }

    .round-stats {
        gap: 2rem;
    }

    .results-comparison {
        flex-direction: column;
        gap: 1rem;
    }

    .comparison-vs {
        transform: rotate(90deg);
    }

    .results-actions {
        flex-direction: column;
        width: 100%;
    }

    .results-actions .btn {
        width: 100%;
    }
}

@media (max-width: 480px) {
    .container {
        padding: 1.5rem;
    }

    #landing .title {
        font-size: 2.5rem;
    }

    .question-text {
        font-size: 1.1rem;
    }

    .option {
        padding: 1rem;
    }

    .results-score {
        font-size: 4rem;
    }
}

/* ===== Animations ===== */
@keyframes fadeIn {
    from {
        opacity: 0;
        transform: translateY(10px);
    }
    to {
        opacity: 1;
        transform: translateY(0);
    }
}

.question-card,
.option {
    animation: fadeIn 0.3s ease forwards;
}

.option:nth-child(1) { animation-delay: 0.05s; }
.option:nth-child(2) { animation-delay: 0.1s; }
.option:nth-child(3) { animation-delay: 0.15s; }
.option:nth-child(4) { animation-delay: 0.2s; }

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

::-webkit-scrollbar-track {
    background: var(--gray-900);
}

::-webkit-scrollbar-thumb {
    background: var(--gray-700);
    border-radius: 4px;
}

::-webkit-scrollbar-thumb:hover {
    background: var(--gray-600);
}

/* ===== Top Bar ===== */
.top-bar {
    position: absolute;
    top: 1.5rem;
    right: 1.5rem;
    display: flex;
    align-items: center;
    gap: 1rem;
}

.sync-indicator {
    display: flex;
    align-items: center;
    gap: 0.5rem;
    padding: 0.5rem 1rem;
    background: var(--gray-900);
    border: 1px solid var(--gray-800);
    border-radius: 20px;
    font-size: 0.85rem;
    color: var(--gray-400);
}

.sync-indicator.synced {
    color: #22c55e;
}

.sync-indicator.syncing {
    color: #fbbf24;
}

.sync-indicator.error {
    color: #ef4444;
}

.btn-icon {
    width: 44px;
    height: 44px;
    padding: 0;
    background: var(--gray-900);
    border: 1px solid var(--gray-800);
    border-radius: 50%;
    color: var(--gray-400);
    transition: all var(--transition-fast);
}

.btn-icon:hover {
    color: var(--white);
    border-color: var(--gray-600);
    background: var(--gray-800);
}

/* ===== Modal ===== */
.modal {
    display: none;
    position: fixed;
    top: 0;
    left: 0;
    width: 100%;
    height: 100%;
    z-index: 1000;
}

.modal.active {
    display: block;
}

.modal-overlay {
    position: absolute;
    top: 0;
    left: 0;
    width: 100%;
    height: 100%;
    background: rgba(0, 0, 0, 0.8);
    backdrop-filter: blur(4px);
}

.modal-content {
    position: absolute;
    top: 50%;
    left: 50%;
    transform: translate(-50%, -50%);
    width: 90%;
    max-width: 480px;
    max-height: 90vh;
    overflow-y: auto;
    background: var(--gray-900);
    border: 1px solid var(--gray-800);
    border-radius: var(--border-radius-lg);
    animation: modalSlideIn 0.3s ease;
}

@keyframes modalSlideIn {
    from {
        opacity: 0;
        transform: translate(-50%, -48%);
    }
    to {
        opacity: 1;
        transform: translate(-50%, -50%);
    }
}

.modal-header {
    display: flex;
    align-items: center;
    justify-content: space-between;
    padding: 1.5rem;
    border-bottom: 1px solid var(--gray-800);
}

.modal-header h2 {
    font-size: 1.25rem;
    font-weight: 600;
}

.modal-close {
    width: 36px;
    height: 36px;
    display: flex;
    align-items: center;
    justify-content: center;
    background: transparent;
    border: none;
    color: var(--gray-400);
    font-size: 1.5rem;
    cursor: pointer;
    border-radius: 8px;
    transition: all var(--transition-fast);
}

.modal-close:hover {
    background: var(--gray-800);
    color: var(--white);
}

.modal-body {
    padding: 1.5rem;
}

/* ===== Settings Section ===== */
.settings-section {
    margin-bottom: 2rem;
}

.settings-section:last-child {
    margin-bottom: 0;
}

.settings-section h3 {
    font-size: 1rem;
    font-weight: 600;
    margin-bottom: 0.5rem;
}

.settings-desc {
    font-size: 0.9rem;
    color: var(--gray-400);
    margin-bottom: 1rem;
}

.auth-section {
    display: flex;
    flex-direction: column;
    gap: 1rem;
}

.settings-input {
    width: 100%;
    padding: 0.875rem 1rem;
    background: var(--gray-800);
    border: 1px solid var(--gray-700);
    border-radius: var(--border-radius);
    color: var(--white);
    font-family: inherit;
    font-size: 0.95rem;
    transition: all var(--transition-fast);
}

.settings-input:focus {
    outline: none;
    border-color: var(--gray-500);
    background: var(--gray-900);
}

.settings-input::placeholder {
    color: var(--gray-500);
}

.settings-help {
    font-size: 0.8rem;
    color: var(--gray-500);
}

.settings-help a {
    color: var(--gray-300);
    text-decoration: underline;
    transition: color var(--transition-fast);
}

.settings-help a:hover {
    color: var(--white);
}

/* User Info */
.user-info {
    display: flex;
    align-items: center;
    gap: 1rem;
    padding: 1rem;
    background: var(--gray-800);
    border-radius: var(--border-radius);
}

.user-avatar {
    width: 48px;
    height: 48px;
    border-radius: 50%;
    object-fit: cover;
}

.user-details {
    display: flex;
    flex-direction: column;
    gap: 0.25rem;
}

.user-name {
    font-weight: 600;
    color: var(--white);
}

.sync-status {
    font-size: 0.8rem;
    color: #22c55e;
}

/* Config Status */
.config-status {
    display: flex;
    align-items: center;
    gap: 0.5rem;
    padding: 1rem;
    background: var(--gray-800);
    border-radius: var(--border-radius);
    color: var(--gray-300);
}

.config-status .status-icon {
    color: #22c55e;
}

/* Button Variations */
.btn-sm {
    padding: 0.5rem 1rem;
    font-size: 0.875rem;
}

.btn-danger {
    color: #ef4444;
    border-color: rgba(239, 68, 68, 0.3);
}

.btn-danger:hover:not(:disabled) {
    background: rgba(239, 68, 68, 0.1);
    border-color: #ef4444;
}

/* ===== AI Analysis Section ===== */
.ai-analysis-section {
    width: 100%;
    background: var(--gray-900);
    border: 1px solid var(--gray-800);
    border-radius: var(--border-radius-lg);
    padding: 1.5rem;
    margin-bottom: 2rem;
    text-align: left;
}

.ai-analysis-header {
    display: flex;
    align-items: center;
    justify-content: space-between;
    margin-bottom: 1rem;
}

.ai-analysis-header h3 {
    font-size: 1rem;
    font-weight: 600;
    color: var(--white);
}

.ai-analysis-content {
    color: var(--gray-300);
}

.analysis-loading {
    display: flex;
    align-items: center;
    justify-content: center;
    gap: 1rem;
    padding: 2rem;
    color: var(--gray-400);
}

.analysis-result {
    line-height: 1.7;
}

.analysis-result h1,
.analysis-result h2,
.analysis-result h3,
.analysis-result h4 {
    color: var(--white);
    margin-top: 1.25rem;
    margin-bottom: 0.5rem;
}

.analysis-result h1 { font-size: 1.25rem; }
.analysis-result h2 { font-size: 1.1rem; }
.analysis-result h3 { font-size: 1rem; }
.analysis-result h4 { font-size: 0.95rem; }

.analysis-result p {
    margin-bottom: 0.75rem;
}

.analysis-result ul,
.analysis-result ol {
    margin: 0.75rem 0;
    padding-left: 1.5rem;
}

.analysis-result li {
    margin-bottom: 0.5rem;
}

.analysis-result strong {
    color: var(--white);
}

.analysis-result code {
    background: var(--gray-800);
    padding: 0.15rem 0.4rem;
    border-radius: 4px;
    font-size: 0.9em;
}

.analysis-unavailable {
    text-align: center;
    padding: 1.5rem;
    color: var(--gray-400);
}

.analysis-unavailable p {
    margin-bottom: 1rem;
}

/* Results container adjustments for scrolling */
.results-container {
    max-height: 100vh;
    overflow-y: auto;
    padding-bottom: 3rem;
}

/* ===== Mobile Adjustments ===== */
@media (max-width: 480px) {
    .top-bar {
        top: 1rem;
        right: 1rem;
    }
    
    .modal-content {
        width: 95%;
        max-height: 85vh;
    }
    
    .modal-header {
        padding: 1rem;
    }
    
    .modal-body {
        padding: 1rem;
    }
    
    .ai-analysis-header {
        flex-direction: column;
        align-items: flex-start;
        gap: 0.75rem;
    }
}