:root {
    --primary-color: #007bff;
    --primary-color-dark: #0056b3;
    --background-color: #f4f7f6;
    --surface-color: #ffffff;
    --text-color: #333333;
    --border-color: #e0e0e0;
    --danger-color: #dc3545;
    --font-family: -apple-system, BlinkMacSystemFont, "Segoe UI", Roboto, Helvetica, Arial, sans-serif;
    --border-radius: 8px;
    --shadow: 0 4px 12px rgba(0, 0, 0, 0.08);
    --transition-speed: 0.3s;
}

*, *::before, *::after {
    box-sizing: border-box;
}

body {
    margin: 0;
    font-family: var(--font-family);
    background-color: var(--background-color);
    color: var(--text-color);
    display: flex;
    justify-content: center;
    align-items: flex-start;
    min-height: 100vh;
    padding: 1rem;
}

.app {
    width: 100%;
    max-width: 720px;
    margin: 0 auto;
    position: relative;
}

.screen {
    display: none;
    flex-direction: column;
    background-color: var(--surface-color);
    border-radius: var(--border-radius);
    box-shadow: var(--shadow);
    overflow: hidden;
    animation: fadeIn 0.5s ease-in-out;
}

.screen[aria-hidden="false"] {
    display: flex;
}

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

.screen--start {
    padding: 3rem 2rem;
    text-align: center;
    align-items: center;
}

.title {
    font-size: 2.5rem;
    font-weight: 700;
    margin: 0 0 0.5rem;
}

.subtitle {
    font-size: 1.1rem;
    color: #666;
    max-width: 500px;
    margin: 0 0 2.5rem;
}

.sex-select {
    display: flex;
    gap: 1.5rem;
    width: 100%;
    justify-content: center;
}

.sex-card {
    flex: 1;
    max-width: 220px;
    padding: 2rem 1rem;
    border: 2px solid var(--border-color);
    border-radius: var(--border-radius);
    font-size: 1.2rem;
    font-weight: 600;
    cursor: pointer;
    background-color: transparent;
    transition: all var(--transition-speed) ease;
    position: relative;
    overflow: hidden;
}

.sex-card:hover, .sex-card:focus-visible {
    transform: translateY(-5px);
    border-color: var(--primary-color);
    box-shadow: 0 8px 20px rgba(0, 123, 255, 0.15);
}

.sex-card::after {
    content: '';
    position: absolute;
    bottom: 0;
    left: 0;
    width: 100%;
    height: 4px;
    background-color: var(--primary-color);
    transform: scaleX(0);
    transition: transform var(--transition-speed) ease;
}

.sex-card:hover::after, .sex-card:focus-visible::after {
    transform: scaleX(1);
}

.screen--question {
    padding: 2rem;
}

.q-header {
    margin-bottom: 2rem;
}

.progress {
    margin-bottom: 1rem;
}

#progress-text {
    font-size: 0.9rem;
    color: #555;
    display: block;
    margin-bottom: 0.5rem;
}

.progress-bar {
    width: 100%;
    height: 8px;
    background-color: #e9ecef;
    border-radius: 4px;
    overflow: hidden;
}

.progress-fill {
    width: 0;
    height: 100%;
    background-color: var(--primary-color);
    transition: width 0.4s ease;
}

.nav-top {
    display: flex;
    justify-content: space-between;
    align-items: center;
}

.btn {
    padding: 0.6rem 1.2rem;
    font-size: 1rem;
    font-weight: 600;
    border-radius: var(--border-radius);
    border: 2px solid transparent;
    cursor: pointer;
    transition: all var(--transition-speed) ease;
    background-color: #f0f0f0;
    color: #333;
}

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

.btn--primary:hover, .btn--primary:focus-visible {
    background-color: var(--primary-color-dark);
    box-shadow: 0 4px 10px rgba(0, 123, 255, 0.2);
}

.btn--ghost {
    background-color: transparent;
    border-color: var(--border-color);
}

.btn--ghost:hover, .btn--ghost:focus-visible {
    background-color: #f8f9fa;
    border-color: #ccc;
}

.btn:disabled {
    opacity: 0.6;
    cursor: not-allowed;
}

.question-container {
    margin-bottom: 2rem;
}

.question-title {
    font-size: 1.5rem;
    font-weight: 600;
    margin: 0 0 1.5rem;
}

.question-help {
    font-size: 0.9rem;
    color: #666;
    margin: -1rem 0 1.5rem;
    border-left: 3px solid var(--border-color);
    padding-left: 1rem;
}

.option-list {
    list-style: none;
    padding: 0;
    margin: 0;
    display: flex;
    flex-direction: column;
    gap: 0.75rem;
}

.option-label {
    display: flex;
    align-items: center;
    padding: 1rem;
    border: 1px solid var(--border-color);
    border-radius: var(--border-radius);
    cursor: pointer;
    transition: all var(--transition-speed) ease;
}

.option-label:hover {
    border-color: var(--primary-color);
    background-color: #f8f9fa;
}

.option-label input {
    margin-right: 0.75rem;
    width: 1.2em;
    height: 1.2em;
}

.option-label.selected {
    border-color: var(--primary-color);
    background-color: #e9f2ff;
}

.q-actions {
    display: flex;
    justify-content: flex-end;
    align-items: center;
    border-top: 1px solid var(--border-color);
    padding-top: 1.5rem;
}

.validation {
    color: var(--danger-color);
    font-weight: 500;
    margin-right: auto;
}

.screen--result {
    padding: 2rem;
    text-align: center;
}

#result-title {
    font-size: 2rem;
    margin-bottom: 1.5rem;
}

.result-content {
    text-align: left;
    line-height: 1.6;
}

.result-section {
    margin-bottom: 2rem;
}

.result-section h3 {
    font-size: 1.3rem;
    color: var(--primary-color);
    border-bottom: 2px solid var(--border-color);
    padding-bottom: 0.5rem;
    margin-bottom: 1rem;
}

.result-actions {
    margin-top: 2.5rem;
    display: flex;
    justify-content: center;
    gap: 1rem;
}

.input-group {
    margin-bottom: 1.5rem;
}

.input-group label {
    display: block;
    font-weight: 600;
    margin-bottom: 0.5rem;
}

.input-field {
    width: 100%;
    padding: 0.8rem 1rem;
    font-size: 1rem;
    border: 1px solid var(--border-color);
    border-radius: var(--border-radius);
    transition: border-color var(--transition-speed);
}

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

.unit-toggle {
    margin-left: 1rem;
    font-size: 0.9rem;
    color: var(--primary-color);
    cursor: pointer;
    text-decoration: underline;
}

@media (max-width: 600px) {
    body {
        padding: 0;
    }
    .app {
        max-width: 100%;
    }
    .screen {
        border-radius: 0;
        min-height: 100vh;
    }
    .screen--start {
        padding: 2rem 1rem;
    }
    .sex-select {
        flex-direction: column;
        align-items: center;
    }
    .sex-card {
        width: 100%;
        max-width: 300px;
    }
    .screen--question, .screen--result {
        padding: 1.5rem 1rem;
    }
    .title {
        font-size: 2rem;
    }
    .q-actions {
        flex-direction: column;
        gap: 1rem;
    }
    #btn-next {
        width: 100%;
    }
    .validation {
        margin-right: 0;
        text-align: center;
    }
}

@media print {
    body {
        background-color: #fff;
        color: #000;
        padding: 0;
    }
    .app {
        box-shadow: none;
        max-width: 100%;
    }
    .screen--result {
        display: block !important;
        padding: 1rem;
    }
    .screen, .q-header, .q-actions, .result-actions {
        display: none;
    }
    #result-title, .result-section h3 {
        color: #000;
        border-bottom: 2px solid #ccc;
    }
    .print-summary {
        display: block !important;
        margin-top: 2rem;
        page-break-before: always;
    }
    .print-summary h3 {
        font-size: 1.2rem;
    }
    .print-summary ul {
        padding-left: 20px;
    }
}

.print-summary {
    display: none;
}