/* Swiss Design Style - Mathematics Quiz */

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

:root {
    /* Swiss Design Color Palette - Minimal & Functional */
    --primary-black: #000000;
    --primary-white: #FFFFFF;
    --neutral-gray: #767676;
    --light-gray: #E8E8E8;
    --accent-red: #FF0000;
    --success-green: #008000;
    --focus-blue: #0066CC;

    /* Typography - Swiss Design favors Helvetica */
    --font-primary: 'Helvetica Neue', Helvetica, Arial, sans-serif;

    /* Grid & Spacing */
    --spacing-unit: 8px;
    --grid-gap: 24px;
    --container-max: 800px;
}

body {
    font-family: var(--font-primary);
    font-size: 16px;
    line-height: 1.5;
    color: var(--primary-black);
    background-color: var(--primary-white);
    -webkit-font-smoothing: antialiased;
    -moz-osx-font-smoothing: grayscale;
}

/* ========== Layout ========== */
.container {
    max-width: var(--container-max);
    margin: 0 auto;
    padding: calc(var(--spacing-unit) * 6) calc(var(--spacing-unit) * 3);
    min-height: 100vh;
}

.screen {
    display: none;
}

.screen.active {
    display: block;
    animation: fadeIn 0.3s ease-in;
}

@keyframes fadeIn {
    from { opacity: 0; }
    to { opacity: 1; }
}

/* ========== Typography ========== */
h1 {
    font-size: 2.5rem;
    font-weight: 700;
    letter-spacing: -0.02em;
    margin-bottom: calc(var(--spacing-unit) * 2);
    line-height: 1.2;
}

h2 {
    font-size: 1.75rem;
    font-weight: 700;
    margin-bottom: calc(var(--spacing-unit) * 2);
    line-height: 1.3;
}

h3 {
    font-size: 1.25rem;
    font-weight: 700;
    margin-bottom: calc(var(--spacing-unit) * 2);
}

p {
    margin-bottom: calc(var(--spacing-unit) * 2);
}

.subtitle {
    font-size: 1.125rem;
    color: var(--neutral-gray);
    margin-bottom: calc(var(--spacing-unit) * 4);
}

/* ========== Buttons - Swiss Design with Gel Effect ========== */
.btn {
    display: inline-block;
    padding: calc(var(--spacing-unit) * 2) calc(var(--spacing-unit) * 4);
    font-family: var(--font-primary);
    font-size: 1rem;
    font-weight: 700;
    text-align: center;
    text-decoration: none;
    border: 2px solid var(--primary-black);
    background-color: var(--primary-white);
    color: var(--primary-black);
    cursor: pointer;
    transition: all 0.2s ease;
    margin-right: calc(var(--spacing-unit) * 2);
    margin-bottom: calc(var(--spacing-unit) * 2);
    position: relative;
    overflow: hidden;
}

/* Gel Button Effect - Late 90s/Early 2000s IMAX Style */
.btn-gel {
    border: none;
    border-radius: 12px;
    background: linear-gradient(to bottom,
        rgba(255, 255, 255, 0.9) 0%,
        rgba(255, 255, 255, 0.4) 45%,
        rgba(0, 0, 0, 0.1) 50%,
        rgba(0, 0, 0, 0.2) 100%
    );
    box-shadow:
        0 8px 16px rgba(0, 0, 0, 0.3),
        inset 0 1px 0 rgba(255, 255, 255, 0.8),
        inset 0 -1px 0 rgba(0, 0, 0, 0.2);
    text-shadow: 0 1px 2px rgba(0, 0, 0, 0.3);
    padding: calc(var(--spacing-unit) * 2.5) calc(var(--spacing-unit) * 5);
}

.btn-gel::before {
    content: '';
    position: absolute;
    top: 0;
    left: 0;
    right: 0;
    height: 50%;
    background: linear-gradient(to bottom,
        rgba(255, 255, 255, 0.6) 0%,
        rgba(255, 255, 255, 0) 100%
    );
    border-radius: 12px 12px 0 0;
}

.btn-gel:active:not(:disabled) {
    transform: translateY(2px);
    box-shadow:
        0 4px 8px rgba(0, 0, 0, 0.3),
        inset 0 1px 0 rgba(255, 255, 255, 0.8);
}

.btn-gel.btn-primary {
    background: linear-gradient(to bottom,
        #4a90e2 0%,
        #2e5c8a 50%,
        #1a3a5c 100%
    );
    color: var(--primary-white);
}

.btn-gel.btn-primary:hover:not(:disabled) {
    background: linear-gradient(to bottom,
        #5aa0f2 0%,
        #3e6c9a 50%,
        #2a4a6c 100%
    );
}

.btn-gel.btn-danger {
    background: linear-gradient(to bottom,
        #ff4444 0%,
        #cc0000 50%,
        #990000 100%
    );
    color: var(--primary-white);
}

.btn:hover:not(:disabled) {
    background-color: var(--primary-black);
    color: var(--primary-white);
}

.btn:focus {
    outline: 3px solid var(--focus-blue);
    outline-offset: 2px;
}

.btn:disabled {
    opacity: 0.5;
    cursor: not-allowed;
    border-color: var(--neutral-gray);
    color: var(--neutral-gray);
}

.btn-gel:disabled {
    background: linear-gradient(to bottom,
        #cccccc 0%,
        #999999 50%,
        #666666 100%
    );
    box-shadow: 0 4px 8px rgba(0, 0, 0, 0.2);
}

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

.btn-primary:hover:not(:disabled) {
    background-color: var(--primary-white);
    color: var(--primary-black);
}

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

.btn-danger {
    border-color: var(--accent-red);
    color: var(--accent-red);
}

.btn-danger:hover:not(:disabled) {
    background-color: var(--accent-red);
    color: var(--primary-white);
}

/* ========== Button Group ========== */
.button-group {
    display: flex;
    gap: calc(var(--spacing-unit) * 2);
    align-items: center;
}

.button-group .btn {
    margin-right: 0;
    margin-bottom: 0;
}

/* ========== Info Box ========== */
.info-box {
    border: 2px solid var(--primary-black);
    padding: calc(var(--spacing-unit) * 3);
    margin-bottom: calc(var(--spacing-unit) * 4);
    background-color: var(--light-gray);
}

.info-box ul {
    margin-left: calc(var(--spacing-unit) * 3);
    margin-top: calc(var(--spacing-unit) * 2);
}

.info-box li {
    margin-bottom: calc(var(--spacing-unit));
}

/* ========== Quiz Interface ========== */
.quiz-header {
    display: grid;
    grid-template-columns: 1fr 1fr;
    gap: var(--grid-gap);
    margin-bottom: calc(var(--spacing-unit) * 4);
    padding-bottom: calc(var(--spacing-unit) * 3);
    border-bottom: 2px solid var(--primary-black);
}

.timer-container {
    text-align: left;
}

.timer-label {
    display: block;
    font-size: 0.875rem;
    font-weight: 700;
    text-transform: uppercase;
    letter-spacing: 0.05em;
    margin-bottom: calc(var(--spacing-unit));
}

.timer {
    font-size: 2rem;
    font-weight: 700;
    color: var(--primary-black);
}

.timer.warning {
    color: var(--accent-red);
}

.timer-unit {
    font-size: 0.875rem;
    color: var(--neutral-gray);
    margin-left: calc(var(--spacing-unit));
}

.progress-container {
    text-align: right;
    display: flex;
    align-items: center;
    justify-content: flex-end;
    font-weight: 700;
}

/* ========== Question Container ========== */
.question-container {
    margin-bottom: calc(var(--spacing-unit) * 4);
}

.question-text {
    font-size: 1.5rem;
    margin-bottom: calc(var(--spacing-unit) * 4);
    padding: calc(var(--spacing-unit) * 3);
    background-color: var(--light-gray);
    border-left: 4px solid var(--primary-black);
}

.answers-container {
    display: grid;
    gap: calc(var(--spacing-unit) * 2);
}

/* ========== Answer Options ========== */
.answer-option {
    position: relative;
    display: block;
    padding: calc(var(--spacing-unit) * 2) calc(var(--spacing-unit) * 3);
    border: 2px solid var(--primary-black);
    background-color: var(--primary-white);
    cursor: pointer;
    transition: all 0.2s ease;
}

.answer-option:hover {
    background-color: var(--light-gray);
}

.answer-option input[type="radio"] {
    position: absolute;
    opacity: 0;
    width: 0;
    height: 0;
}

.answer-option input[type="radio"]:checked + .option-label {
    font-weight: 700;
}

.answer-option input[type="radio"]:checked ~ .option-label::before {
    content: '▶ ';
}

.answer-option input[type="radio"]:focus + .option-label {
    outline: 3px solid var(--focus-blue);
    outline-offset: 2px;
}

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

.option-label {
    display: block;
    cursor: pointer;
    font-size: 1.125rem;
}

/* ========== Results Screen ========== */
.results-container {
    margin-bottom: calc(var(--spacing-unit) * 4);
    padding: calc(var(--spacing-unit) * 4);
    border: 2px solid var(--primary-black);
    text-align: center;
}

.score-display {
    font-size: 2rem;
    font-weight: 700;
    margin-bottom: calc(var(--spacing-unit) * 2);
}

.score-display span {
    color: var(--primary-black);
}

.result-message {
    font-size: 1.125rem;
    margin-bottom: 0;
}

.results-actions {
    text-align: center;
}

/* ========== Admin Panel ========== */
.admin-header {
    display: flex;
    justify-content: space-between;
    align-items: center;
    margin-bottom: calc(var(--spacing-unit) * 4);
    padding-bottom: calc(var(--spacing-unit) * 3);
    border-bottom: 2px solid var(--primary-black);
}

.admin-section {
    margin-bottom: calc(var(--spacing-unit) * 6);
    padding-bottom: calc(var(--spacing-unit) * 6);
    border-bottom: 1px solid var(--light-gray);
}

.admin-section:last-child {
    border-bottom: none;
}

/* ========== Forms ========== */
.question-form {
    max-width: 600px;
}

.form-group {
    margin-bottom: calc(var(--spacing-unit) * 3);
}

.form-group label {
    display: block;
    font-weight: 700;
    margin-bottom: calc(var(--spacing-unit));
    text-transform: uppercase;
    font-size: 0.875rem;
    letter-spacing: 0.05em;
}

.required {
    color: var(--accent-red);
}

.form-group input[type="text"],
.form-group textarea,
.form-group select {
    width: 100%;
    padding: calc(var(--spacing-unit) * 2);
    font-family: var(--font-primary);
    font-size: 1rem;
    border: 2px solid var(--primary-black);
    background-color: var(--primary-white);
    color: var(--primary-black);
}

.form-group input[type="text"]:focus,
.form-group textarea:focus,
.form-group select:focus {
    outline: 3px solid var(--focus-blue);
    outline-offset: 2px;
}

.form-actions {
    margin-top: calc(var(--spacing-unit) * 4);
}

.form-message {
    margin-top: calc(var(--spacing-unit) * 3);
    padding: calc(var(--spacing-unit) * 2);
    border: 2px solid var(--primary-black);
    display: none;
}

.form-message.success {
    background-color: var(--success-green);
    color: var(--primary-white);
    border-color: var(--success-green);
    display: block;
}

.form-message.error {
    background-color: var(--accent-red);
    color: var(--primary-white);
    border-color: var(--accent-red);
    display: block;
}

/* ========== Question List ========== */
.question-bank-actions {
    margin-bottom: calc(var(--spacing-unit) * 3);
}

.question-list {
    display: grid;
    gap: calc(var(--spacing-unit) * 2);
}

.question-item {
    border: 2px solid var(--primary-black);
    padding: calc(var(--spacing-unit) * 3);
    background-color: var(--primary-white);
}

.question-item-header {
    display: flex;
    justify-content: space-between;
    align-items: flex-start;
    margin-bottom: calc(var(--spacing-unit) * 2);
}

.question-item-type {
    font-size: 0.75rem;
    font-weight: 700;
    text-transform: uppercase;
    letter-spacing: 0.05em;
    padding: calc(var(--spacing-unit) / 2) calc(var(--spacing-unit));
    background-color: var(--primary-black);
    color: var(--primary-white);
}

.question-item-text {
    font-weight: 700;
    margin-bottom: calc(var(--spacing-unit) * 2);
}

.question-item-options {
    margin-left: calc(var(--spacing-unit) * 2);
    color: var(--neutral-gray);
}

.question-item-options li {
    margin-bottom: calc(var(--spacing-unit) / 2);
}

.question-item-options .correct {
    color: var(--success-green);
    font-weight: 700;
}

.delete-btn {
    background: none;
    border: none;
    color: var(--accent-red);
    font-size: 1.25rem;
    cursor: pointer;
    padding: calc(var(--spacing-unit));
}

.delete-btn:hover {
    opacity: 0.7;
}

.delete-btn:focus {
    outline: 3px solid var(--focus-blue);
    outline-offset: 2px;
}

/* ========== Responsive Design ========== */
@media (max-width: 768px) {
    .container {
        padding: calc(var(--spacing-unit) * 3) calc(var(--spacing-unit) * 2);
    }

    h1 {
        font-size: 2rem;
    }

    h2 {
        font-size: 1.5rem;
    }

    .quiz-header {
        grid-template-columns: 1fr;
        gap: calc(var(--spacing-unit) * 2);
    }

    .progress-container {
        text-align: left;
        justify-content: flex-start;
    }

    .admin-header {
        flex-direction: column;
        align-items: flex-start;
        gap: calc(var(--spacing-unit) * 2);
    }

    .button-group {
        flex-direction: column;
        width: 100%;
    }

    .button-group .btn {
        width: 100%;
    }
}

/* ========== Accessibility Enhancements ========== */
.visually-hidden {
    position: absolute;
    width: 1px;
    height: 1px;
    padding: 0;
    margin: -1px;
    overflow: hidden;
    clip: rect(0, 0, 0, 0);
    white-space: nowrap;
    border: 0;
}

/* High contrast mode support */
@media (prefers-contrast: high) {
    .btn {
        border-width: 3px;
    }

    .answer-option {
        border-width: 3px;
    }
}

/* Reduced motion support */
@media (prefers-reduced-motion: reduce) {
    * {
        animation: none !important;
        transition: none !important;
    }
}

/* ========== Confetti Animation ========== */
.confetti-container {
    position: fixed;
    top: 0;
    left: 0;
    width: 100%;
    height: 100%;
    pointer-events: none;
    z-index: 1000;
    overflow: hidden;
}

.confetti-piece {
    position: absolute;
    width: 10px;
    height: 10px;
    background: var(--accent-red);
    top: -10px;
    opacity: 0;
    animation: confetti-fall linear forwards;
}

@keyframes confetti-fall {
    0% {
        opacity: 1;
        transform: translateY(0) rotateZ(0deg);
    }
    100% {
        opacity: 0;
        transform: translateY(100vh) rotateZ(720deg);
    }
}

/* ========== Enhanced Success Screen ========== */
.results-container.success {
    background: linear-gradient(135deg, #667eea 0%, #764ba2 100%);
    border: 4px solid #FFD700;
    color: var(--primary-white);
    animation: pulse-success 2s ease-in-out infinite;
}

.results-container.success h1 {
    color: var(--primary-white);
    font-size: 3rem;
    text-shadow: 2px 2px 4px rgba(0, 0, 0, 0.3);
    animation: bounce-in 0.6s ease-out;
}

.results-container.success .score-display {
    color: #FFD700;
    font-size: 2.5rem;
    text-shadow: 2px 2px 4px rgba(0, 0, 0, 0.5);
}

.results-container.success .score-display span {
    color: #FFD700;
}

@keyframes pulse-success {
    0%, 100% {
        transform: scale(1);
    }
    50% {
        transform: scale(1.02);
    }
}

@keyframes bounce-in {
    0% {
        transform: scale(0.3);
        opacity: 0;
    }
    50% {
        transform: scale(1.05);
    }
    70% {
        transform: scale(0.9);
    }
    100% {
        transform: scale(1);
        opacity: 1;
    }
}

/* ========== Enhanced Failure Screen ========== */
.results-container.failure {
    background-color: rgba(255, 0, 0, 0.05);
    border: 2px solid var(--accent-red);
}

.results-container.failure h1 {
    color: var(--accent-red);
}

.results-container.failure .score-display {
    color: var(--accent-red);
}

.results-container.failure .score-display span {
    color: var(--accent-red);
}

.results-container.failure .result-message {
    color: var(--neutral-gray);
}

/* ========== Review Section ========== */
.review-container {
    margin-top: calc(var(--spacing-unit) * 4);
    padding: calc(var(--spacing-unit) * 4);
    border: 2px solid var(--primary-black);
    background-color: var(--light-gray);
}

.review-container h2 {
    margin-bottom: calc(var(--spacing-unit) * 3);
    padding-bottom: calc(var(--spacing-unit) * 2);
    border-bottom: 2px solid var(--primary-black);
}

.review-question {
    margin-bottom: calc(var(--spacing-unit) * 4);
    padding: calc(var(--spacing-unit) * 3);
    background-color: var(--primary-white);
    border-left: 4px solid var(--neutral-gray);
}

.review-question.correct {
    border-left-color: var(--success-green);
    background-color: rgba(0, 128, 0, 0.05);
}

.review-question.incorrect {
    border-left-color: var(--accent-red);
    background-color: rgba(255, 0, 0, 0.05);
}

.review-question-header {
    display: flex;
    justify-content: space-between;
    align-items: center;
    margin-bottom: calc(var(--spacing-unit) * 2);
}

.review-question-number {
    font-weight: 700;
    font-size: 0.875rem;
    text-transform: uppercase;
    letter-spacing: 0.05em;
}

.review-status {
    font-weight: 700;
    font-size: 0.875rem;
    padding: calc(var(--spacing-unit) / 2) calc(var(--spacing-unit));
    border-radius: 4px;
}

.review-status.correct {
    background-color: var(--success-green);
    color: var(--primary-white);
}

.review-status.incorrect {
    background-color: var(--accent-red);
    color: var(--primary-white);
}

.review-question-text {
    font-size: 1.125rem;
    font-weight: 700;
    margin-bottom: calc(var(--spacing-unit) * 2);
}

.review-answers {
    margin-left: calc(var(--spacing-unit) * 2);
}

.review-answer-item {
    padding: calc(var(--spacing-unit)) calc(var(--spacing-unit) * 2);
    margin-bottom: calc(var(--spacing-unit));
    border-radius: 4px;
}

.review-answer-item.user-answer {
    background-color: rgba(0, 102, 204, 0.1);
    border-left: 3px solid var(--focus-blue);
    font-weight: 600;
}

.review-answer-item.correct-answer {
    background-color: rgba(0, 128, 0, 0.1);
    border-left: 3px solid var(--success-green);
    font-weight: 600;
}

.review-answer-label {
    font-size: 0.75rem;
    text-transform: uppercase;
    font-weight: 700;
    letter-spacing: 0.05em;
    color: var(--neutral-gray);
    margin-right: calc(var(--spacing-unit));
}