:root {
    --color-brand: hsl(210, 80%, 55%);
    --color-brand-hover: hsl(210, 80%, 45%);
    --color-brand-light-text: hsl(210, 100%, 95%);
    --color-correct: hsl(145, 63%, 42%);
    --color-correct-hover: hsl(145, 63%, 35%);
    --color-wrong: hsl(0, 72%, 50%);
    --color-wrong-hover: hsl(0, 72%, 40%);
    --bg-light: #f4f7fa;
    --card-bg-light: #ffffff;
    --text-light: #1f2937;
    --text-light-subtle: #6b7280;
    --border-light: #e5e7eb;
    --shadow-light: rgba(0, 0, 0, 0.08);
    --bg-dark: #111827;
    --card-bg-dark: #1f2937;
    --text-dark: #f9fafb;
    --text-dark-subtle: #9ca3af;
    --border-dark: #374151;
    --shadow-dark: rgba(0, 0, 0, 0.2);
    --bg-color: var(--bg-light);
    --card-bg-color: var(--card-bg-light);
    --text-color: var(--text-light);
    --text-subtle-color: var(--text-light-subtle);
    --border-color: var(--border-light);
    --shadow-color: var(--shadow-light);
    --toggle-handle-color: #ffffff;
}
body.dark-mode {
    --bg-color: var(--bg-dark);
    --card-bg-color: var(--card-bg-dark);
    --text-color: var(--text-dark);
    --text-subtle-color: var(--text-dark-subtle);
    --border-color: var(--border-dark);
    --shadow-color: var(--shadow-dark);
    --toggle-handle-color: #374151;
}
* {
    box-sizing: border-box;
    margin: 0;
    padding: 0;
}
html {
    height: 100%;
}
body {
    min-height: 100%;
    font-family: 'Noto Sans JP', sans-serif;
    background-color: var(--bg-color);
    color: var(--text-color);
    transition: background-color 0.3s ease, color 0.3s ease;
}
.header-controls {
    position: absolute;
    top: 20px;
    right: 20px;
    z-index: 950;
    display: flex;
    flex-direction: row;
    align-items: center;
    gap: 0.75rem;
}
body.mode-bebas .header-controls,
body.mode-test .header-controls {
    right: auto;
    left: 20px;
    width: calc(100% - 40px);
    justify-content: space-between;
}
body.menu-page {
    display: flex;
    justify-content: center;
    align-items: flex-start;
    padding: 6vh 20px 150px;
}
.menu-container {
    width: 100%;
    max-width: 700px;
    text-align: center;
    position: relative;
    margin-top: 40px;
}
.menu-container h1 {
    font-size: 2.8rem;
    color: var(--color-brand);
    margin-bottom: 0.5rem;
    font-weight: 700;
}
.menu-container .subtitle {
    font-size: 1.25rem;
    color: var(--text-subtle-color);
    margin-bottom: 2.5rem;
}
.category-list {
    width: 100%;
    display: flex;
    flex-direction: column;
    gap: 0.75rem;
}
.category-item {
    background-color: var(--card-bg-color);
    border-radius: 12px;
    border: 1px solid var(--border-color);
    box-shadow: 0 4px 10px var(--shadow-color);
    overflow: hidden;
    transition: all 0.3s ease-in-out;
}
.category-header {
    font-family: 'Noto Sans JP', sans-serif;
    display: flex;
    justify-content: space-between;
    align-items: center;
    width: 100%;
    padding: 1.25rem 1.5rem;
    font-size: 1.5rem;
    font-weight: 700;
    color: var(--text-color);
    background-color: var(--card-bg-color);
    border: none;
    cursor: pointer;
    transition: background-color 0.2s ease;
}
.category-header:hover {
    background-color: var(--bg-color);
}
.category-item.active .category-header {
    color: var(--color-brand);
}
.category-header .icon {
    font-size: 1.5rem;
    font-weight: 400;
    color: var(--text-subtle-color);
    transition: transform 0.3s ease;
}
.category-item.active .icon {
    transform: rotate(45deg);
    color: var(--color-brand);
}
.category-content {
    max-height: 0;
    overflow: hidden;
    transition: max-height 0.4s ease-in-out;
    padding: 0;
}
.category-content-inner {
    padding: 1.5rem 1.5rem;
}
.chapter-link-grid {
    display: grid;
    grid-template-columns: repeat(auto-fit, minmax(100px, 1fr));
    gap: 1rem;
    align-items: stretch;
}
.chapter-link {
    font-family: 'Noto Sans JP', sans-serif;
    font-size: 1rem;
    font-weight: 700;
    text-decoration: none;
    color: var(--text-color);
    background-color: var(--bg-color);
    padding: 1rem;
    border-radius: 10px;
    border: 1px solid var(--border-color);
    transition: all 0.2s ease;
    width: 100%;
    display: flex;
    justify-content: center;
    align-items: center;
    aspect-ratio: 1 / 0.6;
    box-shadow: 0 2px 5px var(--shadow-color);
    cursor: pointer;
}
.chapter-link:hover {
    background-color: var(--color-brand);
    color: white;
    border-color: var(--color-brand-hover);
    transform: translateY(-3px);
    box-shadow: 0 4px 10px var(--shadow-color);
}
.chapter-link.selected {
    background-color: var(--color-brand);
    color: white;
    border-color: var(--color-brand-hover);
    transform: translateY(-3px);
    box-shadow: 0 4px 10px var(--shadow-color);
}
.watermark-logo-menu {
    position: absolute;
    top: 20px;
    left: 50%;
    transform: translateX(-50%);
    width: 60px;
    height: auto;
    opacity: 0.5;
    z-index: 10;
    user-select: none;
    -webkit-user-drag: none;
}
body.dark-mode .watermark-logo-menu {
    opacity: 0.7;
    filter: invert(1);
}
.app-container {
    display: flex;
    flex-direction: column;
    min-height: 100vh;
    padding: 20px;
    position: relative;
    padding-bottom: calc(var(--controls-height, 230px) + env(safe-area-inset-bottom));
    transition: padding-bottom 0.3s ease;
}
#back-to-menu-btn {
    position: static;
}
.theme-toggle-btn {
    width: 50px;
    height: 50px;
    display: flex;
    justify-content: center;
    align-items: center;
    background-color: var(--card-bg-color);
    border: 1px solid var(--border-color);
    border-radius: 50%;
    cursor: pointer;
    transition: all 0.2s ease;
    box-shadow: 0 2px 8px var(--shadow-color);
    -webkit-tap-highlight-color: transparent;
    padding: 0;
    overflow: hidden;
}
.theme-toggle-btn:hover {
    transform: translateY(-2px);
    box-shadow: 0 4px 12px var(--shadow-color);
}
.theme-toggle-btn img {
    width: 24px;
    height: 24px;
    filter: invert(0.5);
    position: absolute;
    transition: opacity 0.3s ease, transform 0.3s ease;
}
body.dark-mode .theme-toggle-btn img {
    filter: invert(0.8);
}
.theme-toggle-btn .icon-sun { opacity: 1; transform: scale(1) rotate(0deg); }
.theme-toggle-btn .icon-moon { opacity: 0; transform: scale(0) rotate(90deg); }
body.dark-mode .theme-toggle-btn .icon-sun { opacity: 0; transform: scale(0) rotate(-90deg); }
body.dark-mode .theme-toggle-btn .icon-moon { opacity: 1; transform: scale(1) rotate(0deg); }
.card-scene-wrapper {
    flex-grow: 1;
    display: flex;
    justify-content: center;
    align-items: center;
    width: 100%;
    position: relative;
    margin-top: 40px;
}
.watermark-logo {
    position: absolute;
    top: -30px;
    left: 50%;
    transform: translateX(-50%);
    width: 60px;
    height: auto;
    opacity: 0.5;
    z-index: 5;
    user-select: none;
    -webkit-user-drag: none;
}
body.dark-mode .watermark-logo {
    opacity: 0.7;
    filter: invert(1);
}
.card-scene {
    width: 90vw;
    max-width: 500px;
    height: 55vh;
    max-height: 350px;
    perspective: 1500px;
    transition: transform 0.2s ease-out;
}
.app-container.is-changing .card-scene { transform: scale(0.95); transition-timing-function: ease-in; }
.card { width: 100%; height: 100%; position: relative; transform-style: preserve-3d; transition: transform 0.6s cubic-bezier(0.25, 0.46, 0.45, 0.94); cursor: pointer; }
.card.is-flipped { transform: rotateX(180deg); }
.card__face {
    position: absolute;
    width: 100%;
    height: 100%;
    backface-visibility: hidden;
    display: flex;
    justify-content: center;
    align-items: center;
    font-weight: 700;
    text-align: center;
    padding: 25px;
    background-color: var(--card-bg-color);
    color: var(--text-color);
    border-radius: 16px;
    box-shadow: 0 8px 24px var(--shadow-color);
    border: 2px solid var(--border-color);
    transition: background-color 0.3s ease, color 0.3s ease, border-color 0.3s ease;
}
.card__face--front { font-size: 4.5rem; }
.card__face--back { transform: rotateX(180deg); flex-direction: column; justify-content: center; align-items: center; line-height: 1.6; padding: 30px; }
.card__face--back .hiragana {
    font-size: 2.2rem;
    font-weight: 700;
    color: var(--color-brand);
    margin-bottom: 15px;
}
.card__face--back .definition { font-size: 1.6rem; font-weight: 500; margin-bottom: 20px; }
.card__face--back .level {
    font-size: 1rem;
    font-weight: 700;
    color: var(--text-subtle-color);
    position: absolute;
    bottom: 20px;
    right: 25px;
    background-color: var(--bg-color);
    padding: 5px 10px;
    border-radius: 5px;
    transition: background-color 0.3s ease;
}
.controls-container {
    position: fixed;
    bottom: 0;
    left: 0;
    width: 100%;
    background-color: var(--bg-color);
    border-top: 1px solid var(--border-color);
    display: flex;
    flex-direction: column;
    align-items: center;
    gap: 10px;
    padding: 1rem 20px;
    padding-bottom: calc(1rem + env(safe-area-inset-bottom));
    z-index: 50;
    box-shadow: 0 -4px 15px var(--shadow-color);
    transition: height 0.3s ease;
}
.autoplay-controls {
    width: 100%;
    max-width: 500px;
    flex-direction: column;
    align-items: center;
    gap: 5px;
    color: var(--text-subtle-color);
}
.autoplay-controls label {
    font-size: 0.9rem;
    font-weight: 600;
}
.speed-slider {
    width: 80%;
    max-width: 300px;
    cursor: pointer;
    accent-color: var(--color-brand);
}
.progress-bar-container {
    width: 100%;
    max-width: 500px;
    height: 10px;
    background-color: var(--border-color);
    border-radius: 10px;
    overflow: hidden;
}
.progress-bar {
    width: 0%;
    height: 100%;
    background-color: var(--color-brand);
    border-radius: 10px;
    transition: width 0.4s cubic-bezier(0.25, 1, 0.5, 1);
}
.button-bar {
    display: flex;
    flex-direction: row;
    justify-content: center;
    align-items: center;
    gap: 1rem;
    width: 100%;
    max-width: 500px;
}
.nav-btn-svg, .shuffle-btn {
    width: 50px;
    height: 50px;
    display: flex;
    justify-content: center;
    align-items: center;
    background-color: var(--card-bg-color);
    border: 1px solid var(--border-color);
    border-radius: 50%;
    cursor: pointer;
    transition: all 0.2s ease;
    box-shadow: 0 2px 8px var(--shadow-color);
    -webkit-tap-highlight-color: transparent;
}
.nav-btn-svg:hover, .shuffle-btn:hover {
    transform: translateY(-2px);
    box-shadow: 0 4px 12px var(--shadow-color);
}
.nav-btn-svg:active, .shuffle-btn:active {
    transform: scale(0.95);
}
.shuffle-btn img, .nav-btn-svg img {
    width: 24px;
    height: 24px;
    transition: filter 0.3s ease;
    filter: invert(0.5);
}
body.dark-mode .shuffle-btn img,
body.dark-mode .nav-btn-svg img {
    filter: invert(0.8);
}
.shuffle-btn:hover img, .nav-btn-svg:hover img {
    filter: invert(0.3);
}
body.dark-mode .shuffle-btn:hover img,
body.dark-mode .nav-btn-svg:hover img {
    filter: invert(1);
}
.shuffle-btn.active,
.nav-btn-svg.active {
    background-color: var(--color-brand);
    border-color: var(--color-brand);
}
.shuffle-btn.active img,
.nav-btn-svg.active img {
    filter: invert(1);
}
body.dark-mode .shuffle-btn.active img,
body.dark-mode .nav-btn-svg.active img {
    filter: invert(1);
}
.controls-test #wrong-button-svg,
.controls-test #correct-button-svg {
    display: none;
}
.btn-action {
    font-family: 'Noto Sans JP', sans-serif;
    font-size: 1.1rem;
    font-weight: 700;
    color: white;
    border: none;
    border-radius: 50px;
    padding: 0.8rem;
    height: 60px;
    cursor: pointer;
    flex-grow: 1;
    display: flex;
    justify-content: center;
    align-items: center;
    gap: 0.5rem;
    box-shadow: 0 4px 15px -5px rgba(0,0,0,0.3);
    transition: all 0.2s ease;
    -webkit-tap-highlight-color: transparent;
}
.btn-action img {
    width: 20px;
    height: 20px;
    filter: invert(1);
}
.btn-action:hover {
    transform: translateY(-3px);
    box-shadow: 0 6px 20px -5px rgba(0,0,0,0.4);
}
.btn-action:active {
    transform: scale(0.98);
    box-shadow: 0 2px 10px -5px rgba(0,0,0,0.3);
}
#btn-action-wrong {
    background-color: var(--color-wrong);
}
#btn-action-wrong:hover {
    background-color: var(--color-wrong-hover);
}
#btn-action-correct {
    background-color: var(--color-correct);
}
#btn-action-correct:hover {
    background-color: var(--color-correct-hover);
}
.card-counter {
    font-size: 1.2rem;
    font-weight: 600;
    color: var(--text-subtle-color);
}
.nav-instructions {
    display: none;
}
.controls-bebas,
.controls-test {
    display: none;
    flex-direction: row;
    justify-content: center;
    align-items: center;
    gap: 1rem;
    width: 100%;
}
body.mode-bebas .controls-bebas {
    display: flex;
    justify-content: space-around;
}
body.mode-test .controls-test {
    display: flex;
    justify-content: center;
    align-items: center;
    gap: 0.75rem;
}
.controls-test #prev-button-svg-test {
    width: 50px;
    height: 50px;
}
.controls-test #shuffle-button-test {
    width: 50px;
    height: 50px;
}
.modal-overlay {
    position: fixed;
    top: 0;
    left: 0;
    width: 100%;
    height: 100%;
    background-color: rgba(0, 0, 0, 0.6);
    display: flex;
    justify-content: center;
    align-items: center;
    z-index: 1000;
    backdrop-filter: blur(5px);
}
.modal-content {
    background-color: var(--card-bg-color);
    padding: 2.5rem;
    border-radius: 16px;
    text-align: center;
    box-shadow: 0 10px 30px var(--shadow-color);
    position: relative;
    width: 90%;
    max-width: 400px;
}
.modal-content h3 {
    font-size: 1.6rem;
    margin-bottom: 2rem;
    color: var(--text-color);
}
.modal-buttons {
    display: flex;
    flex-direction: column;
    gap: 1rem;
}
.modal-button {
    font-family: 'Noto Sans JP', sans-serif;
    font-size: 1.1rem;
    font-weight: 700;
    padding: 0.8rem 1.5rem;
    border: none;
    border-radius: 10px;
    cursor: pointer;
    transition: all 0.2s ease;
}
.modal-button.btn-primary {
    background-color: var(--color-brand);
    color: white;
}
.modal-button.btn-primary:hover {
    background-color: var(--color-brand-hover);
    transform: scale(1.03);
}
.modal-button.btn-secondary {
    background-color: transparent;
    color: var(--color-brand);
    border: 2px solid var(--color-brand);
}
.modal-button.btn-secondary:hover {
    background-color: var(--bg-color);
    transform: scale(1.03);
}
.modal-close-btn {
    position: absolute;
    top: 15px;
    right: 20px;
    font-size: 2.2rem;
    color: var(--text-subtle-color);
    background: none;
    border: none;
    cursor: pointer;
    transition: color 0.2s ease;
}
.modal-close-btn:hover {
    color: var(--text-color);
}
.selection-bar {
    position: fixed;
    bottom: 0;
    left: 0;
    width: 100%;
    background-color: var(--card-bg-color);
    border-top: 1px solid var(--border-color);
    box-shadow: 0 -4px 15px var(--shadow-color);
    display: flex;
    justify-content: space-between;
    align-items: center;
    padding: 1rem 1.5rem;
    padding-bottom: calc(1rem + env(safe-area-inset-bottom));
    z-index: 900;
}
.selection-info {
    font-size: 1.1rem;
    font-weight: 600;
    color: var(--text-subtle-color);
}
.selection-info span {
    color: var(--color-brand);
    font-weight: 700;
}
.selection-start-btn {
    font-family: 'Noto Sans JP', sans-serif;
    font-size: 1.1rem;
    font-weight: 700;
    background-color: var(--color-brand);
    color: white;
    border: none;
    border-radius: 10px;
    padding: 0.8rem 1.5rem;
    cursor: pointer;
    transition: all 0.2s ease;
}
.selection-start-btn:hover {
    background-color: var(--color-brand-hover);
    transform: scale(1.03);
}
.contact-fab-container {
    position: relative;
}
.contact-fab {
    width: 50px;
    height: 50px;
    display: flex;
    justify-content: center;
    align-items: center;
    background-color: var(--card-bg-color);
    border: 1px solid var(--border-color);
    border-radius: 50%;
    cursor: pointer;
    transition: all 0.2s ease;
    box-shadow: 0 2px 8px var(--shadow-color);
    -webkit-tap-highlight-color: transparent;
    padding: 0;
}
.contact-fab:hover {
    transform: translateY(-2px);
    box-shadow: 0 4px 12px var(--shadow-color);
}
.contact-fab svg {
    stroke: var(--text-subtle-color);
    width: 24px;
    height: 24px;
    transition: stroke 0.3s ease;
}
.contact-fab:hover svg {
    stroke: var(--text-color);
}
body.dark-mode .contact-fab svg {
    stroke: var(--text-dark-subtle);
}
body.dark-mode .contact-fab:hover svg {
    stroke: var(--text-dark);
}
/* ATURAN BARU UNTUK IKON IMG */
.contact-fab img {
    width: 24px;
    height: 24px;
    transition: filter 0.3s ease;
    filter: invert(0.5);
}
.contact-fab:hover img {
    filter: invert(0.3);
}
body.dark-mode .contact-fab img {
    filter: invert(0.8);
}
body.dark-mode .contact-fab:hover img {
    filter: invert(1);
}
/* AKHIR ATURAN BARU */
.contact-menu {
    position: absolute;
    top: 60px;
    right: 0;
    width: 280px;
    background-color: var(--card-bg-color);
    border-radius: 12px;
    box-shadow: 0 6px 20px var(--shadow-color);
    padding: 1rem;
    display: flex;
    flex-direction: column;
    gap: 1rem;
    opacity: 0;
    visibility: hidden;
    transform: translateY(10px);
    transition: opacity 0.3s ease, visibility 0.3s ease, transform 0.3s ease;
    z-index: 960;
}
.contact-menu.show-menu {
    opacity: 1;
    visibility: visible;
    transform: translateY(0);
}
.contact-section {
    border-bottom: 1px solid var(--border-color);
    padding-bottom: 1rem;
}
.contact-section:last-child {
    border-bottom: none;
    padding-bottom: 0;
}
.contact-description {
    font-size: 0.9rem;
    color: var(--text-subtle-color);
    margin-bottom: 0.8rem;
    line-height: 1.4;
}
.contact-icons {
    display: flex;
    justify-content: center;
    gap: 1.5rem;
}
.contact-icons a {
    display: inline-block;
    transition: transform 0.2s ease;
}
.contact-icons a:hover {
    transform: scale(1.15);
}
.contact-icons img {
    width: 32px;
    height: 32px;
    filter: invert(0.5);
}
body.dark-mode .contact-icons img {
    filter: invert(0.8);
}
@media (max-width: 600px) {
    .card__face--front { font-size: 3.5rem; }
    .card__face--back .hiragana { font-size: 1.8rem; }
    .card__face--back .definition { font-size: 1.3rem; }
    #back-to-menu-btn { width: 44px; height: 44px; }
    #back-to-menu-btn img { width: 20px; height: 20px; }
    .header-controls {
        top: 15px;
        right: 15px;
        gap: 0.5rem;
    }
    body.mode-bebas .header-controls,
    body.mode-test .header-controls {
        right: auto;
        left: 15px;
        width: calc(100% - 30px);
        justify-content: space-between;
    }
    .theme-toggle-btn {
        width: 44px;
        height: 44px;
    }
    .theme-toggle-btn img {
        width: 20px;
        height: 20px;
    }
    .controls-test {
        gap: 0.5rem;
    }
    .controls-test #prev-button-svg-test {
        position: static;
        width: 44px;
        height: 44px;
    }
    .controls-test #shuffle-button-test {
        width: 44px;
        height: 44px;
    }
    .controls-test #prev-button-svg-test img,
    .controls-test #shuffle-button-test img {
        width: 20px;
        height: 20px;
    }
    .btn-action {
        height: 55px;
        font-size: 1rem;
    }
    
    .contact-fab {
        width: 44px;
        height: 44px;
    }
    .contact-fab svg {
        width: 20px;
        height: 20px;
    }
    /* ATURAN BARU UNTUK IKON IMG */
    .contact-fab img {
        width: 20px;
        height: 20px;
    }
    /* AKHIR ATURAN BARU */
    .contact-menu {
        top: 50px;
        width: calc(100vw - 40px);
        max-width: 280px;
        right: 0;
        left: auto;
    }
    .contact-icons img {
        width: 30px;
        height: 30px;
    }
    .selection-bar {
        padding: 0.75rem 1rem;
        padding-bottom: calc(0.75rem + env(safe-area-inset-bottom));
    }
    .selection-info {
        font-size: 1rem;
    }
    .selection-start-btn {
        font-size: 1rem;
        padding: 0.7rem 1.2rem;
    }
}