:root {
    /* Japanese Traditional Colors */
    --jp-indigo: #2e4a62;
    --jp-blue: #3b6c9b;
    --jp-red: #c9171e;
    --jp-paper: #f4f1ea;
    --jp-bamboo: #d3def1;
    --jp-gold: #d4af37;

    /* Semantic Variables (Light Mode Default) */
    --bg-color: var(--jp-paper);
    --text-color: #333;
    --card-bg: #fff;
    --navbar-bg: linear-gradient(135deg, var(--jp-indigo), var(--jp-blue));
    --navbar-text: #fff;
    --btn-primary-bg: linear-gradient(135deg, var(--jp-indigo), var(--jp-blue));
    --btn-primary-text: #fff;
    --input-bg: #fff;
    --input-text: #333;
    --border-color: rgba(0, 0, 0, 0.1);
}

body.dark-mode {
    --bg-color: #121212;
    --text-color: #e0e0e0;
    --card-bg: #1e1e1e;
    --navbar-bg: linear-gradient(135deg, #0f2027, #203a43, #2c5364);
    /* Deep dark blue gradient */
    --navbar-text: #e0e0e0;
    /* Keep the primary button gradient consistent but maybe slightly brighter or same */
    --btn-primary-bg: linear-gradient(135deg, #3b6c9b, #2e4a62);
    --input-bg: #2c2c2c;
    --input-text: #e0e0e0;
    --border-color: rgba(255, 255, 255, 0.1);
}

body {
    background-color: var(--bg-color);
    font-family: 'Noto Sans JP', 'Helvetica Neue', Helvetica, Arial, sans-serif;
    color: var(--text-color);
    margin: 0;
    padding: 0;
    overflow-x: hidden;
    transition: background-color 0.3s ease, color 0.3s ease;
}

/* Navbar Tweaks */
.navbar {
    background: var(--navbar-bg) !important;
    border-bottom: 3px solid rgba(0, 0, 0, 0.05);
}

.navbar-light .navbar-brand,
.navbar-light .nav-link,
.text-light {
    color: var(--navbar-text) !important;
}

/* Card Styling */
.card {
    border-radius: 12px;
    transition: transform 0.2s ease, box-shadow 0.2s ease, background-color 0.3s ease;
    border: 1px solid var(--border-color);
    background-color: var(--card-bg);
    color: var(--text-color);
}

.menu-card:hover {
    transform: translateY(-5px);
    cursor: pointer;
    box-shadow: 0 10px 20px rgba(0, 0, 0, 0.2) !important;
}

/* Buttons */
.btn-primary,
.btn-gradient-blue {
    background: var(--btn-primary-bg);
    border: none;
    color: var(--btn-primary-text);
    transition: opacity 0.2s;
}

.btn-primary:hover,
.btn-gradient-blue:hover {
    opacity: 0.9;
    color: var(--btn-primary-text);
}

.btn-outline-dark {
    color: var(--text-color);
    border-color: var(--text-color);
}

.btn-outline-dark:hover {
    background-color: var(--text-color);
    color: var(--bg-color);
}

.text-muted {
    color: #888 !important;
    /* Force readable muted in dark mode */
}

/* Form Inputs */
.form-control {
    background-color: var(--input-bg);
    color: var(--input-text);
    border-color: var(--border-color);
}

.form-control:focus {
    background-color: var(--input-bg);
    color: var(--input-text);
}

/* Misc */
.exercise-card {
    background-color: var(--card-bg);
    border-left: 5px solid var(--jp-blue);
}

.hint-box {
    background-color: rgba(59, 108, 155, 0.1);
    /* Transparent blue for adaptability */
    border-radius: 6px;
    border-left: 4px solid var(--jp-indigo);
    color: var(--text-color);
}

/* Typography */
.japanese-text {
    font-family: 'Noto Sans JP', sans-serif;
    font-weight: 500;
}

/* Animations */
.fade-in {
    animation: fadeIn 0.4s ease-in-out;
}

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

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

.correct-animation {
    animation: pulse-green 0.5s ease-in-out;
    border-color: #28a745 !important;
}

@keyframes pulse-green {
    0% {
        transform: scale(1);
    }

    50% {
        transform: scale(1.02);
    }

    100% {
        transform: scale(1);
    }
}

/* Word Chips */
.word-chip {
    border-radius: 20px;
    font-weight: 500;
    transition: all 0.2s;
    background-color: var(--card-bg);
    color: var(--text-color);
    border: 1px solid var(--text-color);
}

.word-chip:hover:not(:disabled) {
    background-color: var(--jp-blue);
    color: white;
    border-color: var(--jp-blue);
}

/* Scrollbar */
::-webkit-scrollbar {
    width: 8px;
}

::-webkit-scrollbar-track {
    background: var(--bg-color);
}

::-webkit-scrollbar-thumb {
    background: #888;
    border-radius: 4px;
}

::-webkit-scrollbar-thumb:hover {
    background: #555;
}

/* Dark Mode Overrides for Bootstrap Utilities */
body.dark-mode .bg-light {
    background-color: #2c2c2c !important;
    color: #e0e0e0 !important;
}

body.dark-mode .bg-white {
    background-color: #1e1e1e !important;
    color: #e0e0e0 !important;
}

body.dark-mode .text-primary {
    color: #6ea8fe !important;
    /* Lighter blue for dark backgrounds */
}

body.dark-mode .border {
    border-color: var(--border-color) !important;
}

/* Dark Mode Accordions */
body.dark-mode .accordion-item {
    background-color: var(--card-bg);
    border-color: var(--border-color);
}

body.dark-mode .accordion-button {
    background-color: var(--card-bg);
    color: var(--text-color);
}

body.dark-mode .accordion-button:not(.collapsed) {
    background-color: rgba(59, 108, 155, 0.3);
    color: #fff;
}

body.dark-mode .accordion-button::after {
    filter: invert(1);
}

/* Dark Mode Inputs */
body.dark-mode .form-control::placeholder {
    color: #aaa;
    opacity: 0.7;
}

body.dark-mode .form-control {
    background-color: var(--input-bg);
    color: var(--input-text);
    border-color: var(--border-color);
}

body.dark-mode .form-control:focus {
    background-color: #333;
    color: #fff;
    border-color: #3b6c9b;
}

/* Fix Bootstrap Validation States in Dark Mode */
body.dark-mode .form-control.is-valid,
body.dark-mode .was-validated .form-control:valid {
    background-color: #1e3a2e;
    /* Dark Green tint */
    border-color: #198754;
    color: #e0e0e0;
    background-image: none !important;
    /* Remove the checkmark icon if it clashes, or keep it. Let's keep it but ensure bg is dark. */
    background-image: url("data:image/svg+xml,%3csvg xmlns='http://www.w3.org/2000/svg' viewBox='0 0 8 8'%3e%3cpath fill='%23198754' d='M2.3 6.73L.6 4.53c-.4-1.04.46-1.4 1.1-.8l1.1 1.4 3.4-3.8c.6-.63 1.6-.27 1.2.7l-4 4.6c-.43.5-.8.4-1.1.1z'/%3e%3c/svg%3e") !important;
}

body.dark-mode .form-control.is-invalid,
body.dark-mode .was-validated .form-control:invalid {
    background-color: #3a1e1e;
    /* Dark Red tint */
    border-color: #dc3545;
    color: #e0e0e0;
    background-image: url("data:image/svg+xml,%3csvg xmlns='http://www.w3.org/2000/svg' viewBox='0 0 12 12' width='12' height='12' fill='none' stroke='%23dc3545'%3e%3ccircle cx='6' cy='6' r='4.5'/%3e%3cpath stroke-linejoin='round' d='M5.8 3.6h.4L6 6.5z'/%3e%3ccircle cx='6' cy='8.2' r='.6' fill='%23dc3545' stroke='none'/%3e%3c/svg%3e") !important;
}

/* Dark Mode Modals */
body.dark-mode .modal-content {
    background-color: var(--card-bg);
    border: 1px solid var(--border-color);
}

body.dark-mode .modal-header {
    border-bottom-color: var(--border-color);
}

body.dark-mode .modal-footer {
    border-top-color: var(--border-color);
}

body.dark-mode .btn-close {
    filter: invert(1);
}

/* Dark Mode Tables */
body.dark-mode .table {
    --bs-table-bg: transparent;
    --bs-table-color: var(--text-color);
    --bs-table-striped-bg: rgba(255, 255, 255, 0.05);
    --bs-table-striped-color: var(--text-color);
    --bs-table-active-bg: rgba(255, 255, 255, 0.1);
    --bs-table-active-color: var(--text-color);
    --bs-table-hover-bg: rgba(255, 255, 255, 0.075);
    --bs-table-hover-color: var(--text-color);
    color: var(--text-color);
    border-color: var(--border-color);
}

body.dark-mode .table-hover>tbody>tr:hover>* {
    color: var(--text-color);
    background-color: var(--bs-table-hover-bg);
}

body.dark-mode .table-light {
    --bs-table-bg: #2c2c2c;
    --bs-table-color: #e0e0e0;
    background-color: #2c2c2c;
    color: #e0e0e0;
}

/* Dark Mode List Groups */
body.dark-mode .list-group-item {
    background-color: var(--card-bg);
    color: var(--text-color);
    border-color: var(--border-color);
}

body.dark-mode .list-group-item.active {
    background-color: #3b6c9b;
    border-color: #3b6c9b;
    color: #fff;
}

body.dark-mode .list-group-item-action:hover:not(.active) {
    background-color: #2c2c2c;
    color: #e0e0e0;
}