* {
    margin: 0;
    padding: 0;
    box-sizing: border-box;
}

@import url('https://fonts.googleapis.com/css2?family=Crimson+Text:ital@0;1&display=swap');

:root {
    /* Colores temáticos */
    --azul-oscuro: rgb(14, 2, 102);
    --rojo: rgb(122, 0, 0);
    --blanco: #ffffff;
    --gris-claro: #f5f5f5;
    --gris-medio: #e0e0e0;
    --gris-oscuro: #333333;
    --verde: #10b981;
    --naranja: #f59e0b;
    
    --shadow: 0 10px 30px rgba(0, 0, 0, 0.15);
    --shadow-sm: 0 4px 12px rgba(0, 0, 0, 0.1);
}

html, body {
    width: 100%;
    height: 100%;
}

body {
    font-family: 'Segoe UI', Tahoma, Geneva, Verdana, sans-serif;
    background: var(--blanco);
    color: var(--gris-oscuro);
    padding: 0;
    margin: 0;
}

/* ====== PAGE WRAPPER Y HEADER ====== */
.page-wrapper {
    display: flex;
    flex-direction: column;
    min-height: 100vh;
    border: 25px solid var(--azul-oscuro);
    background: var(--blanco);
}

.page-header {
    background: var(--blanco);
    padding: 20px 40px;
    border-bottom: 4px solid var(--rojo);
    position: relative;
    display: flex;
    justify-content: center;
    align-items: center;
}

.header-content {
    display: flex;
    justify-content: center;
    align-items: center;
    width: 100%;
    position: relative;
}

.page-title {
    font-size: 2.8em;
    font-weight: 900;
    color: var(--azul-oscuro);
    text-align: center;
    letter-spacing: 2px;
    font-family: 'Crimson Text', serif;
}

/* ====== MAIN FRAME ====== */
.main-frame {
    flex: 1;
    padding: 30px;
    overflow-y: auto;
}

.container {
    width: 100%;
    max-width: 700px;
    margin: 0 auto;
}

/* ====== LÍNEAS DE SEPARACIÓN ====== */
.separator {
    border: none;
    border-top: 3px solid var(--rojo);
    margin: 25px 0;
    opacity: 0.8;
}

/* Pantalla */
.screen {
    display: none;
    animation: fadeIn 0.4s ease-in;
}

.screen.active {
    display: block;
}

@keyframes fadeIn {
    from {
        opacity: 0;
        transform: translateY(15px);
    }
    to {
        opacity: 1;
        transform: translateY(0);
    }
}

/* ====== PANTALLA INICIAL ====== */
.start-content,
.countdown-content,
.game-content,
.results-content {
    background: var(--blanco);
    border-radius: 15px;
    padding: 30px;
    border: 2px solid var(--azul-oscuro);
}

.app-header {
    text-align: center;
    margin-bottom: 20px;
}

.app-title {
    font-size: 2.2em;
    color: var(--azul-oscuro);
    margin-bottom: 8px;
    text-align: center;
    font-weight: 900;
    font-family: 'Crimson Text', serif;
}

.app-subtitle {
    text-align: center;
    font-size: 1.1em;
    color: var(--azul-oscuro);
    font-weight: 500;
}

.selection-section {
    margin-bottom: 20px;
}

.section-title {
    font-size: 1.2em;
    color: var(--rojo);
    margin-bottom: 18px;
    font-weight: 700;
    text-transform: uppercase;
    letter-spacing: 1px;
}

/* Grid de opciones de modalidad */
.options-grid {
    display: grid;
    grid-template-columns: repeat(auto-fit, minmax(110px, 1fr));
    gap: 12px;
    margin-bottom: 15px;
}

.option-card {
    position: relative;
    cursor: pointer;
}

.option-card input {
    display: none;
}

.option-card input:checked + .option-label {
    background: var(--azul-oscuro);
    color: var(--blanco);
    border-color: var(--rojo);
    box-shadow: 0 0 0 3px rgba(122, 0, 0, 0.2);
}

.option-label {
    display: block;
    padding: 12px 10px 8px;
    border: 2px solid var(--azul-oscuro);
    border-radius: 10px;
    text-align: center;
    font-weight: 600;
    transition: all 0.3s ease;
    color: var(--gris-oscuro);
    background: var(--gris-claro);
    font-size: 0.9em;
}

.option-card:hover .option-label {
    border-color: var(--rojo);
    background: #f0f4ff;
}

.option-icon {
    display: block;
    font-size: 1.4em;
    margin-top: 6px;
}

/* Grid de duración */
.duration-grid {
    display: grid;
    grid-template-columns: repeat(2, 1fr);
    gap: 12px;
}

.duration-card {
    position: relative;
    cursor: pointer;
}

.duration-card input {
    display: none;
}

.duration-card input:checked + .duration-value {
    background: var(--azul-oscuro);
    color: var(--blanco);
    border-color: var(--rojo);
}

.duration-value {
    display: block;
    font-size: 2em;
    font-weight: 900;
    text-align: center;
    padding: 18px 12px 8px;
    border: 2px solid var(--azul-oscuro);
    border-radius: 10px;
    transition: all 0.3s ease;
    color: var(--azul-oscuro);
    background: var(--gris-claro);
}

.duration-unit {
    display: block;
    font-size: 0.8em;
    text-align: center;
    padding-bottom: 8px;
    color: var(--gris-oscuro);
    font-weight: 600;
}

.duration-card:hover .duration-value {
    border-color: var(--rojo);
    background: #f0f4ff;
}

/* Resumen de configuración */
.config-summary {
    background: linear-gradient(135deg, #f0f4ff 0%, #fff5f0 100%);
    border-left: 4px solid var(--rojo);
    border: 2px solid var(--azul-oscuro);
    padding: 15px 20px;
    border-radius: 8px;
    margin: 20px 0;
    text-align: center;
}

#configText {
    color: var(--azul-oscuro);
    font-weight: 600;
    font-size: 0.95em;
}

/* Botones */
.btn-primary {
    padding: 13px 35px;
    border: 2px solid transparent;
    border-radius: 8px;
    font-size: 1.05em;
    cursor: pointer;
    font-weight: 700;
    transition: all 0.3s ease;
    text-transform: uppercase;
    letter-spacing: 1px;
    background: var(--azul-oscuro);
    color: var(--blanco);
    width: 100%;
    margin-top: 15px;
    border: 2px solid var(--azul-oscuro);
}

.btn-primary:hover {
    background: var(--azul-oscuro);
    transform: translateY(-3px);
    box-shadow: 0 12px 25px rgba(14, 2, 102, 0.3);
}

.btn-primary:active {
    transform: translateY(-1px);
}

/* ====== PANTALLA COUNTDOWN ====== */
.countdown-content {
    text-align: center;
    padding: 60px 40px;
}

.countdown-content p {
    font-size: 1.3em;
    color: var(--azul-oscuro);
    margin-bottom: 30px;
    font-weight: 600;
}

.countdown-number {
    font-size: 5.5em;
    font-weight: 900;
    color: var(--azul-oscuro);
    font-family: 'Crimson Text', serif;
    animation: countdownPulse 1s ease-out;
}

@keyframes countdownPulse {
    0% {
        transform: scale(1);
        opacity: 1;
    }
    50% {
        transform: scale(1.3);
    }
    100% {
        transform: scale(1);
        opacity: 0.8;
    }
}

/* ====== PANTALLA DEL JUEGO ====== */
.game-header {
    display: flex;
    justify-content: space-between;
    align-items: center;
    margin-bottom: 20px;
    flex-wrap: wrap;
    gap: 15px;
}

.timer {
    display: flex;
    align-items: center;
    gap: 10px;
    font-size: 1.1em;
    font-weight: 700;
    background: var(--azul-oscuro);
    color: var(--blanco);
    padding: 10px 20px;
    border-radius: 8px;
    box-shadow: var(--shadow-sm);
}

.timer-value {
    font-size: 1.5em;
    font-weight: 900;
}

.stats {
    display: flex;
    gap: 15px;
    flex-wrap: wrap;
}

.stat-item {
    display: flex;
    flex-direction: column;
    align-items: center;
    background: var(--gris-claro);
    padding: 8px 12px;
    border-radius: 8px;
    border: 2px solid var(--azul-oscuro);
}

.stat-label {
    font-size: 0.85em;
    color: var(--gris-oscuro);
    font-weight: 600;
}

.stat-value {
    font-size: 1.6em;
    font-weight: 900;
    color: var(--rojo);
}

.operation-card {
    background: linear-gradient(135deg, #f0f4ff 0%, #fff5f0 100%);
    border: 3px solid var(--azul-oscuro);
    border-radius: 12px;
    padding: 45px 25px;
    text-align: center;
    margin-bottom: 25px;
    box-shadow: var(--shadow-sm);
    min-height: 150px;
    display: flex;
    align-items: center;
    justify-content: center;
    position: relative;
}

.operation {
    font-size: 3.2em;
    font-weight: 900;
    color: var(--rojo);
    letter-spacing: 3px;
    font-family: 'Crimson Text', serif;
    line-height: 1.2;
}

/* Checkmark animation for correct answers */
.checkmark {
    position: absolute;
    font-size: 4em;
    color: var(--verde);
    animation: checkmarkPop 0.8s ease-out forwards;
    pointer-events: none;
}

@keyframes checkmarkPop {
    0% {
        transform: scale(0) rotate(-45deg);
        opacity: 1;
    }
    50% {
        transform: scale(1.3) rotate(10deg);
    }
    100% {
        transform: scale(1) translateY(-80px);
        opacity: 0;
    }
}

/* Correct answer animation for incorrect answers */
.correct-answer-display {
    position: absolute;
    font-size: 2.5em;
    color: var(--verde);
    font-family: 'Crimson Text', serif;
    font-weight: 700;
    animation: correctAnswerFloat 1.2s ease-out forwards;
    pointer-events: none;
}

@keyframes correctAnswerFloat {
    0% {
        opacity: 1;
        transform: translateY(0) scale(1);
    }
    100% {
        opacity: 0;
        transform: translateY(-60px) scale(1.1);
    }
}

.input-section {
    display: flex;
    gap: 10px;
    margin-bottom: 18px;
}

.answer-input {
    flex: 1;
    padding: 14px;
    font-size: 1.2em;
    border: 2px solid var(--azul-oscuro);
    border-radius: 8px;
    transition: all 0.3s ease;
    font-weight: 600;
    color: var(--gris-oscuro);
}

.answer-input:focus {
    outline: none;
    border-color: var(--rojo);
    box-shadow: 0 0 0 3px rgba(122, 0, 0, 0.1);
    background: #f0f4ff;
}

.feedback-message {
    min-height: 35px;
    text-align: center;
    font-weight: 700;
    font-size: 1.1em;
    padding: 10px;
    border-radius: 8px;
    animation: feedbackAnimation 0.5s ease;
}

.feedback-message.correct {
    color: var(--verde);
    background: #ecfdf5;
    border-left: 4px solid var(--verde);
}

.feedback-message.incorrect {
    color: var(--rojo);
    background: #fff5f5;
    border-left: 4px solid var(--rojo);
}

@keyframes feedbackAnimation {
    0% {
        opacity: 0;
        transform: scale(0.9);
    }
    100% {
        opacity: 1;
        transform: scale(1);
    }
}

/* ====== PANTALLA DE RESULTADOS ====== */
.results-content h2 {
    font-size: 2em;
    color: var(--azul-oscuro);
    text-align: center;
    margin-bottom: 15px;
    font-weight: 900;
    font-family: 'Crimson Text', serif;
}

.results-stats {
    background: var(--gris-claro);
    border-radius: 10px;
    padding: 25px;
    margin: 20px 0;
    border: 2px solid var(--azul-oscuro);
}

.result-item {
    display: flex;
    justify-content: space-between;
    align-items: center;
    padding: 12px 0;
    border-bottom: 2px solid var(--rojo);
}

.result-item:last-child {
    border-bottom: none;
}

.result-label {
    font-size: 1em;
    color: var(--gris-oscuro);
    font-weight: 700;
}

.result-value {
    font-size: 1.6em;
    font-weight: 900;
    color: var(--rojo);
}

.result-value.score {
    font-size: 2.2em;
    color: var(--verde);
}

.results-feedback {
    background: linear-gradient(135deg, #f0f4ff 0%, #fff5f0 100%);
    border-left: 4px solid var(--azul-oscuro);
    border: 2px solid var(--azul-oscuro);
    padding: 20px;
    border-radius: 8px;
    margin-bottom: 20px;
    font-size: 1.1em;
    color: var(--azul-oscuro);
    text-align: center;
    font-weight: 700;
}

/* ====== TIMER WARNING ====== */
.timer.low-time {
    background: var(--rojo);
    animation: timerWarning 0.6s ease infinite;
}

@keyframes timerWarning {
    0%, 100% {
        transform: scale(1);
    }
    50% {
        transform: scale(1.08);
    }
}

/* ====== FOOTER ====== */
.page-footer {
    background: var(--blanco);
    padding: 40px 30px;
    border-top: 4px solid var(--rojo);
    text-align: center;
    flex-shrink: 0;
}

.footer-content {
    max-width: 700px;
    margin: 0 auto;
    display: flex;
    flex-direction: column;
    align-items: center;
    gap: 15px;
}

.footer-logo {
    height: 90px;
    width: auto;
    object-fit: contain;
    filter: drop-shadow(0 2px 4px rgba(0, 0, 0, 0.1));
}

.footer-text {
    font-size: 0.95em;
    color: var(--azul-oscuro);
    font-weight: 600;
    line-height: 1.6;
    max-width: 500px;
}

/* ====== RESPONSIVE ====== */
@media (max-width: 768px) {
    .page-wrapper {
        border: 20px solid var(--azul-oscuro);
    }

    .page-header {
        padding: 15px 20px;
    }

    .page-title {
        font-size: 2em;
    }

    .main-frame {
        padding: 20px;
    }

    .page-footer {
        padding: 30px 20px;
    }

    .footer-logo {
        height: 70px;
    }

    .footer-text {
        font-size: 0.9em;
    }
}

@media (max-width: 600px) {
    .page-wrapper {
        border: 15px solid var(--azul-oscuro);
    }

    .page-header {
        padding: 12px 15px;
    }

    .page-title {
        font-size: 1.6em;
    }

    .main-frame {
        padding: 15px;
    }

    .start-content,
    .countdown-content,
    .game-content,
    .results-content {
        padding: 20px;
    }

    .app-title {
        font-size: 1.8em;
    }

    .app-subtitle {
        font-size: 1em;
    }

    .section-title {
        font-size: 1em;
    }

    .options-grid {
        grid-template-columns: repeat(2, 1fr);
        gap: 10px;
    }

    .duration-grid {
        grid-template-columns: 1fr;
    }

    .operation {
        font-size: 2.5em;
    }

    .countdown-number {
        font-size: 4em;
    }

    .game-header {
        flex-direction: column;
    }

    .timer {
        width: 100%;
        justify-content: center;
    }

    .stats {
        width: 100%;
        justify-content: space-around;
    }

    .input-section {
        flex-direction: column;
    }

    .result-item {
        flex-direction: column;
        align-items: flex-start;
        gap: 8px;
    }

    .result-value {
        align-self: flex-end;
    }

    .page-footer {
        padding: 20px 15px;
    }

    .footer-logo {
        height: 60px;
    }

    .footer-text {
        font-size: 0.85em;
    }
}

@media (max-width: 400px) {
    .page-title {
        font-size: 1.3em;
    }

    .options-grid {
        grid-template-columns: 1fr;
    }

    .option-label {
        font-size: 0.85em;
    }

    .operation {
        font-size: 2em;
    }

    .answer-input {
        font-size: 1em;
        padding: 12px;
    }

    .footer-logo {
        height: 50px;
    }

    .footer-text {
        font-size: 0.8em;
    }
}