:root {
    --bg-color: #f3f4f6;
    --primary-color: #2563eb;
    --primary-hover: #1d4ed8;
    --secondary-color: #9ca3af;
    --secondary-hover: #6b7280;

    --card-bg: #ffffff;
    --text-main: #1f2937;
    --text-muted: #6b7280;
    --border-radius: 12px;
    --shadow: 0 4px 6px -1px rgba(0, 0, 0, 0.1),
        0 2px 4px -1px rgba(0, 0, 0, 0.06);
}

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

body {
    font-family: 'Noto Sans JP', sans-serif;
    background-color: var(--bg-color);
}

/* Responsive Layouts */
@media (max-width: 768px) {
    .container {
        height: 100%;
        justify-content: flex-start;
        gap: 10px;
        padding: 10px;
    }

    .card {
        padding: 16px;
        gap: 10px;
        overflow-y: auto;
        flex-shrink: 1;
    }

    .input-section {
        margin-top: auto;
        flex-shrink: 0;
        background: var(--bg-color);
        padding-top: 10px;
        z-index: 10;
    }

    .info-block {
        padding-bottom: 8px;
    }

    .content-text {
        font-size: 1rem;
    }

    .label {
        font-size: 0.75rem;
        margin-bottom: 2px;
    }

    .btn {
        padding: 12px;
    }

    input[type="text"].main-input {
        padding: 12px;
    }
}

header h1 {
    font-size: 1.8rem;
    color: var(--primary-color);
    margin-bottom: 5px;
    margin-right: 15px;
}

header p {
    color: var(--text-muted);
    font-size: 0.9rem;
    width: 100%;
    flex-basis: 100%;
}

header {
    display: flex;
    flex-wrap: wrap;
    align-items: center;
    position: relative;
}

.stats-container {
    display: flex;
    flex-direction: column;
    justify-content: center;
    font-size: 0.85rem;
    color: var(--text-muted);
    font-weight: bold;
    background: #f3f4f6;
    padding: 4px 8px;
    border-radius: 6px;
    margin-right: auto;
}

.stat-item {
    line-height: 1.2;
}

.card {
    background: var(--card-bg);
    border-radius: var(--border-radius);
    padding: 24px;
    box-shadow: var(--shadow);
    display: flex;
    flex-direction: column;
    gap: 20px;
}

.info-block {
    border-bottom: 1px solid #e5e7eb;
    padding-bottom: 12px;
}

.info-block:last-child {
    border-bottom: none;
    padding-bottom: 0;
}

.info-block-header {
    display: flex;
    justify-content: space-between;
    align-items: center;
    margin-bottom: 4px;
}

.label {
    display: block;
    font-size: 0.85rem;
    font-weight: 700;
    color: var(--text-muted);
    text-transform: uppercase;
    letter-spacing: 0.05em;
}

.mask-toggle {
    display: flex;
    align-items: center;
    gap: 6px;
    font-size: 0.85rem;
    color: var(--text-muted);
    cursor: pointer;
    user-select: none;
}

.mask-toggle input {
    cursor: pointer;
}

.content-text {
    font-size: 1.2rem;
    font-weight: 500;
    white-space: pre-line;
}

#innervation-input {
    width: 100%;
    padding: 8px 12px;
    font-size: 1.1rem;
    border: 2px solid #e5e7eb;
    border-radius: 8px;
    outline: none;
    transition: border-color 0.2s;
    margin-top: 4px;
}

#innervation-input:focus {
    border-color: var(--primary-color);
}

.input-section {
    display: flex;
    flex-direction: column;
    gap: 12px;
}

input[type="text"].main-input {
    width: 100%;
    padding: 16px;
    font-size: 1.1rem;
    border: 2px solid #e5e7eb;
    border-radius: var(--border-radius);
    outline: none;
    transition: border-color 0.2s;
}

input[type="text"].main-input:focus {
    border-color: var(--primary-color);
}

.btn {
    width: 100%;
    padding: 16px;
    font-size: 1.1rem;
    font-weight: 700;
    border: none;
    border-radius: var(--border-radius);
    cursor: pointer;
    transition: background-color 0.2s;
    color: white;
}

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

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

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

.btn.secondary:hover {
    background-color: var(--secondary-hover);
}

.feedback {
    padding: 16px;
    border-radius: var(--border-radius);
    text-align: center;
    font-weight: bold;
    font-size: 1.2rem;
    animation: fadeIn 0.3s ease;
}

.feedback.correct {
    background-color: #d1fae5;
    color: #065f46;
    border: 1px solid #a7f3d0;
}

.feedback.incorrect {
    background-color: #fee2e2;
    color: #991b1b;
    border: 1px solid #fecaca;
}

.hidden {
    display: none;
}

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

    to {
        opacity: 1;
        transform: translateY(0);
    }
}

/* Region Selector */
.region-selector {
    background: #f9fafb;
    border-radius: var(--border-radius);
    border: 1px solid #e5e7eb;
    margin-top: 10px;
    overflow: hidden;
    transition: all 0.3s ease;
}

.region-header {
    display: flex;
    justify-content: space-between;
    align-items: center;
    padding: 16px;
    cursor: pointer;
    background: #f9fafb;
    user-select: none;
}

.region-header:hover {
    background: #f3f4f6;
}

.region-selector h3 {
    font-size: 1rem;
    color: var(--text-muted);
    margin: 0;
    font-weight: 700;
}

.toggle-icon {
    font-size: 0.8rem;
    color: var(--text-muted);
    transition: transform 0.3s ease;
}

.region-selector.open .toggle-icon {
    transform: rotate(180deg);
}

.region-content {
    max-height: 0;
    opacity: 0;
    padding: 0 16px;
    transition: all 0.3s ease;
    visibility: hidden;
}

.region-selector.open .region-content {
    max-height: 500px;
    opacity: 1;
    padding-bottom: 16px;
    visibility: visible;
}

.checkbox-group {
    display: flex;
    flex-wrap: wrap;
    gap: 12px;
    margin-bottom: 12px;
}

.checkbox-group label {
    display: flex;
    align-items: center;
    gap: 6px;
    cursor: pointer;
    font-size: 0.95rem;
    user-select: none;
}

.btn.outline {
    background-color: transparent;
    border: 2px solid var(--primary-color);
    color: var(--primary-color);
    padding: 10px;
    font-size: 1rem;
}

.btn.outline:hover {
    background-color: #eff6ff;
}

/* Mobile Menu Button */
.mobile-menu-btn {
    display: none;
    position: absolute;
    top: 15px;
    right: 15px;
    width: 40px;
    height: 40px;
    background: transparent;
    border: none;
    cursor: pointer;
    z-index: 1001;
    flex-direction: column;
    justify-content: center;
    align-items: center;
    gap: 6px;
    padding: 0;
}

.mobile-menu-btn span {
    display: block;
    width: 24px;
    height: 2px;
    background-color: var(--primary-color);
    transition: all 0.3s ease;
}

/* Mobile Styles & Overlay */
@media (max-width: 768px) {
    header h1 {
        font-size: 1.5rem;
    }

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

    .mobile-menu-btn {
        display: flex;
    }

    .region-selector {
        display: none;
    }

    .region-selector.overlay-open {
        display: flex;
        flex-direction: column;
        position: fixed;
        top: 0;
        left: 0;
        width: 100%;
        height: 100%;
        background: rgba(255, 255, 255, 0.98);
        z-index: 1000;
        margin: 0;
        border-radius: 0;
        padding: 20px;
        box-shadow: none;
        border: none;
    }

    .region-selector.overlay-open .region-header {
        display: none;
    }

    .region-selector.overlay-open .region-content {
        max-height: none;
        opacity: 1;
        visibility: visible;
        padding: 60px 0 20px;
        flex-grow: 1;
        overflow-y: auto;
        display: flex;
        flex-direction: column;
    }

    .region-selector.overlay-open .checkbox-group {
        display: flex;
        flex-direction: column;
        gap: 15px;
        margin-bottom: auto;
    }

    .region-selector.overlay-open .checkbox-group label {
        display: flex;
        flex-direction: row-reverse;
        justify-content: space-between;
        align-items: center;
        width: 100%;
        padding: 15px;
        background: #f3f4f6;
        border-radius: 8px;
        font-size: 1.1rem;
        font-weight: bold;
    }

    .region-selector.overlay-open .checkbox-group label input {
        width: 24px;
        height: 24px;
    }

    .region-selector.overlay-open #update-range-btn {
        display: block;
        width: 100%;
        padding: 16px;
        background-color: var(--primary-color);
        color: white;
        border: none;
        font-weight: bold;
        margin-top: 20px;
        border-radius: var(--border-radius);
    }

    body.menu-open .mobile-menu-btn span:nth-child(1) {
        transform: translateY(8px) rotate(45deg);
    }

    body.menu-open .mobile-menu-btn span:nth-child(2) {
        opacity: 0;
    }

    body.menu-open .mobile-menu-btn span:nth-child(3) {
        transform: translateY(-8px) rotate(-45deg);
    }
}