:root {
    --color-primary: #4361ee;
    --color-primary-light: #4895ef;
    --color-primary-dark: #3a0ca3;
    --color-secondary: #4cc9f0;
    --color-secondary-light: #72efdd;
    --color-secondary-dark: #3f8efc;
    --color-accent: #f72585;
    --color-accent-light: #ff8fab;
    --color-accent-dark: #b5179e;
    --color-success: #4CAF50;
    --color-error: #F44336;
    --color-neutral-50: #f8fafc;
    --color-neutral-100: #f1f5f9;
    --color-neutral-200: #e2e8f0;
    --color-neutral-800: #1e293b;
    --radius-md: 0.5rem;
    --shadow-md: 0 4px 6px -1px rgba(67, 97, 238, 0.08), 0 2px 4px -1px rgba(67, 97, 238, 0.04);
    --pane-bg: #fff;
    --pane-border: var(--color-neutral-200);
}

body {
    font-family: -apple-system, BlinkMacSystemFont, 'Segoe UI', Roboto, Oxygen, Ubuntu, Cantarell, sans-serif;
    line-height: 1.6;
    color: var(--color-neutral-800);
    background-color: var(--color-neutral-50);
    font-size: 0.97em;
    min-height: 100vh;
    overflow-x: hidden;
}

.simulation-container {
    width: 90vw;
    max-width: 1400px;
    margin: 0 auto;
    padding: 0;
    display: flex;
    flex-direction: column;
    align-items: center;
    justify-content: center;
    box-sizing: border-box;
}

.main-content {
    width: 100%;
    max-width: 1400px;
    margin: 0 auto;
    box-sizing: border-box;
    justify-items: center;
    display: grid;
    grid-template-rows: auto 1fr;
}

.instructions-bar, .instructions-panel {
    width: 100%;
    max-width: 1400px;
    margin: 1.2rem auto 1.2rem auto;
    box-sizing: border-box;
    display: flex;
    flex-direction: column;
    align-items: stretch;
    justify-content: center;
    padding: 0;
    border-radius: 0.75rem;
    grid-row: 1;
    grid-column: 1 / -1;
}
.instructions-header.clickable {
    display: flex;
    align-items: center;
    justify-content: center;
    gap: 0.7em;
    width: 100%;
    min-width: 0;
    max-width: 100%;
    cursor: pointer;
    padding: 0.7em 0;
    background: linear-gradient(90deg, #6ef2e6 0%, #4895ef 100%);
    border-radius: 1.2em 1.2em 0 0;
    transition: background 0.2s, box-shadow 0.2s;
    box-shadow: 0 2px 8px rgba(67,97,238,0.04);
    border-bottom: 1px solid var(--color-neutral-200);
    margin: 0;
    position: relative;
}
.instructions-header.clickable:hover, .instructions-header.clickable:focus {
    background: var(--color-secondary-light);
    box-shadow: 0 4px 16px rgba(67,97,238,0.10);
}
.instructions-header.clickable i.fas.fa-info-circle {
    font-size: 1.4em;
    color: var(--color-primary-dark);
    margin-left: 0.5em;
    display: flex;
    align-items: center;
}
.instructions-header.clickable h3 {
    margin: 0;
    font-size: 1.2em;
    font-weight: 700;
    color: #2a1a6e;
    letter-spacing: 0.01em;
    text-align: center;
    flex: 0 0 auto;
    display: flex;
    align-items: center;
}
.instructions-header .arrow-icon {
    margin-left: 0.7em;
    font-size: 1.3em;
    color: var(--color-primary-dark);
    display: flex;
    align-items: center;
}
.instructions-content {
    background-color: white;
    padding: 1rem;
    border: 1px solid var(--color-neutral-200);
    border-top: none;
    border-radius: 0 0 var(--radius-md) var(--radius-md);
    transition: max-height 0.3s ease-out, opacity 0.3s ease-out;
    max-height: 500px;
    opacity: 1;
    overflow: hidden;
}
.instructions-content.collapsed {
    max-height: 0;
    opacity: 0;
    padding-top: 0;
    padding-bottom: 0;
    border-bottom: none;
}
.instructions-list {
    list-style: disc inside;
    margin: 0.2em 0 0.2em 1em;
    padding: 0;
    font-size: 1em;
    color: var(--color-neutral-800);
    line-height: 1.5;
}
.instructions-list li {
    margin-bottom: 0.3em;
}

.three-pane-layout {
    display: grid;
    grid-template-columns: 1fr 1fr 1fr;
    gap: 2rem;
    width: 100%;
    max-width: 1400px;
    margin: 0 auto;
    box-sizing: border-box;
    justify-items: center;
    grid-row: 2;
    grid-column: 1 / -1;
}
.pane {
    box-sizing: border-box;
    width: 100%;
    min-width: 300px;
    max-width: 480px;
    padding: 1rem 0.5rem;
    box-shadow: var(--shadow-md);
    border-radius: var(--radius-md);
    border: 1px solid var(--pane-border);
    margin: 0 auto;
    background: #fff;
    display: flex;
    flex-direction: column;
}
.pane-header {
    display: flex;
    align-items: center;
    gap: 8px;
    margin-bottom: 18px;
}
.pane-header h3 {
    font-size: 1.1rem;
    color: var(--color-primary);
    margin: 0;
    flex: 1;
}
.pane-header .fa-info-circle {
    color: var(--color-primary);
    font-size: 1rem;
}

.features-grid {
    display: grid;
    grid-template-columns: 1fr 1fr;
    gap: 1.1rem 1.5rem;
    justify-content: flex-start;
    align-items: start;
    padding: 0;
    margin: 0;
}
.feature-group {
    display: flex;
    flex-direction: column;
    gap: 0.3rem;
    margin: 0;
    padding: 0;
    background: none;
    border: none;
}
.feature-group label {
    font-size: 0.98rem;
    font-weight: 600;
    color: var(--color-primary-dark);
    margin-bottom: 0.1rem;
}
select, .select-box {
    width: 100%;
    min-width: 100px;
    max-width: 160px;
    font-size: 0.98rem;
    padding: 0.35rem 0.5rem;
    margin: 0;
    border-radius: var(--radius-md);
    border: 1px solid var(--color-neutral-300);
    background-color: var(--color-neutral-100);
    color: var(--color-neutral-800);
    transition: all 0.2s;
}
select:disabled {
    background-color: var(--color-neutral-200);
    cursor: not-allowed;
}
select:focus {
    outline: 2px solid var(--color-primary);
    border-color: var(--color-primary);
    box-shadow: 0 0 0 2px rgba(67, 97, 238, 0.10);
}

.button-group, .button-container {
    margin-top: 20px;
    display: flex;
    gap: 0.5rem;
    flex-wrap: wrap;
    justify-content: flex-start;
}
.primary-button, .secondary-button, #resetButton {
    border: none;
    border-radius: 2.2em;
    font-size: 1.08em;
    font-weight: 700;
    padding: 0.7em 1.7em;
    margin: 0.2em 0.2em 0.2em 0;
    box-shadow: 0 2px 8px rgba(67,97,238,0.08);
    transition: background 0.2s, color 0.2s, box-shadow 0.2s, transform 0.1s;
    outline: none;
    cursor: pointer;
    display: inline-flex;
    align-items: center;
    gap: 0.5em;
}
.primary-button {
    background: linear-gradient(90deg, var(--color-primary) 60%, var(--color-secondary) 100%);
    color: #fff;
}
.primary-button:hover, .primary-button:focus {
    background: linear-gradient(90deg, var(--color-primary-dark) 60%, var(--color-accent) 100%);
    color: #fff;
    transform: translateY(-2px) scale(1.03);
    box-shadow: 0 4px 16px rgba(67,97,238,0.13);
}
.secondary-button, #resetButton {
    background: linear-gradient(90deg, var(--color-secondary) 60%, var(--color-accent-light) 100%);
    color: #fff;
}
.secondary-button:hover, .secondary-button:focus, #resetButton:hover, #resetButton:focus {
    background: linear-gradient(90deg, var(--color-secondary-dark) 60%, var(--color-accent) 100%);
    color: #fff;
    transform: translateY(-2px) scale(1.03);
    box-shadow: 0 4px 16px rgba(67,97,238,0.13);
}
button:disabled {
    opacity: 0.6;
    cursor: not-allowed;
}

.feedback-container, .feedback {
    margin-top: 20px;
    padding: 10px;
    border-radius: 4px;
    font-weight: 500;
}
.feedback.error {
    background-color: #ffebee;
    color: var(--color-error);
}
.feedback.success {
    background-color: #e8f5e9;
    color: var(--color-success);
}

.answer-container {
    margin-top: 0.7em;
    padding: 0.7em 0.5em;
    background: var(--color-neutral-100);
    border-radius: var(--radius-md);
    box-shadow: var(--shadow-md);
    font-size: 1em;
    color: var(--color-neutral-800);
    line-height: 1.7;
    letter-spacing: 0.01em;
    display: block;
}
.answer-container div {
    margin-bottom: 0.2em;
    padding-left: 0.1em;
}

.info-icon, .pane-header .fa-info-circle, .feature-group label i {
    color: var(--color-primary-dark) !important;
    background: var(--color-secondary-light);
    border-radius: 50%;
    width: 1.3em;
    height: 1.3em;
    text-align: center;
    line-height: 1.3em;
    font-weight: bold;
    border: 1px solid var(--color-primary-light);
    font-size: 0.9rem;
    margin-left: 0.5rem;
    display: inline-flex;
    align-items: center;
    justify-content: center;
}

.selection-block {
    display: grid;
    grid-template-columns: 1fr 1fr;
    gap: 1.1rem 1.5rem;
    margin-top: 0.5rem;
}
.form-group {
    display: flex;
    flex-direction: column;
    gap: 0.3rem;
}
.highlight-incorrect {
    border: 2px solid #F44336 !important;
    background: #ffeaea !important;
    box-shadow: 0 0 0 2px #f4433622;
    transition: border 0.2s, background 0.2s;
}

@media (max-width: 1100px) {
    .main-content, .three-pane-layout {
        max-width: 100vw;
        width: 100vw;
        padding-left: 0.5rem;
        padding-right: 0.5rem;
    }
    .pane {
        max-width: 98vw;
    }
    .instructions-bar, .instructions-panel {
        max-width: 100vw;
    }
}
@media (max-width: 900px) {
    .main-content {
        grid-template-rows: auto 1fr;
        max-width: 100vw;
        width: 100vw;
        padding-left: 0.2rem;
        padding-right: 0.2rem;
    }
    .instructions-bar, .instructions-panel {
        margin-bottom: 0.7rem;
        width: 100vw;
        padding-left: 0;
        padding-right: 0;
    }
    .three-pane-layout {
        display: block !important;
        width: 100vw;
        gap: 0;
        justify-items: unset;
        grid-template-columns: unset;
    }
    .pane {
        display: block;
        width: 100% !important;
        max-width: 100% !important;
        min-width: 0;
        margin: 0 auto 1.2rem auto;
        padding: 0.7rem 0.1rem;
        word-break: break-word;
        overflow-wrap: break-word;
        box-sizing: border-box;
    }
    .pane:last-child {
        margin-bottom: 0;
    }
    .feature-group label, .form-group label {
        font-size: 1em;
        word-break: break-word;
        overflow-wrap: break-word;
    }
    .button-group, .button-container {
        flex-direction: column;
        align-items: stretch;
        gap: 0.3rem;
    }
    .features-grid, .selection-block {
        grid-template-columns: 1fr;
        gap: 0.7rem 0;
    }
}
@media (max-width: 600px) {
    .main-content {
        padding-left: 0.2rem;
        padding-right: 0.2rem;
    }
    .instructions-bar, .instructions-panel {
        padding-left: 0.2rem;
        padding-right: 0.2rem;
    }
    .three-pane-layout {
        gap: 0.3rem;
    }
    .pane {
        padding: 0.5rem 0.1rem;
    }
    .features-grid, .selection-block {
        gap: 0.2rem;
    }
    .feature-group, .form-group {
        padding: 0.2rem 0.1rem;
        gap: 0.1rem;
    }
    .feature-group label, .form-group label {
        font-size: 0.93em;
    }
    select, .select-box {
        font-size: 0.93em;
        padding: 0.15rem 0.3rem;
    }
    .button-group, .button-container {
        gap: 0.2rem;
    }
    .primary-button, .secondary-button {
        padding: 0.3rem 0.7rem;
        font-size: 0.93em;
    }
}