:root {
    /* Color Scheme */
    --primary-color: #58CC02;
    /*  Green */
    --primary-shadow: #58A700;
    --secondary-color: #1CB0F6;
    /* Sky Blue */
    --secondary-shadow: #1899D6;
    --wrong-red: #FF4B4B;
    --wrong-shadow: #EA2B2B;
    --bg-color: #FFFFFF;
    --text-main: #4B4B4B;
    --text-light: #AFAFAF;
    --border-color: #E5E5E5;
    --card-bg: #FFFFFF;
    --hover-overlay: rgba(0, 0, 0, 0.05);

    --font-main: 'Nunito', sans-serif;
}

/* Global Reset & Base */
* {
    box-sizing: border-box;
    margin: 0;
    padding: 0;
    font-family: var(--font-main);
}

body {
    background-color: var(--bg-color);
    color: var(--text-main);
    display: flex;
    justify-content: center;
    min-height: 100vh;
}

#app-container {
    width: 100%;
    max-width: 600px;
    /* Mobile First, max-width for Desktop View */
    display: flex;
    flex-direction: column;
    padding: 20px;
    padding-bottom: 80px;
    /* Space for bottom nav */
    position: relative;
    overflow-x: hidden;
}

/* Header & Navigation */
#main-header {
    display: flex;
    justify-content: space-between;
    align-items: center;
    padding: 10px 0 20px 0;
}

#btn-back {
    background: none;
    border: none;
    color: var(--text-light);
    font-size: 1rem;
    font-weight: bold;
    cursor: pointer;
}


#progress-container {
    flex-grow: 1;
    height: 16px;
    background-color: var(--border-color);
    border-radius: 8px;
    margin: 0 20px;
    overflow: hidden;
}

#progress-fill {
    height: 100%;
    width: 0%;
    background-color: var(--primary-color);
    transition: width 0.3s ease;
    border-radius: 8px;
}

/* Bottom Navigation */
#bottom-nav {
    position: fixed;
    bottom: 0;
    left: 50%;
    transform: translateX(-50%);
    width: 100%;
    max-width: 600px;
    background-color: var(--card-bg);
    border-top: 2px solid var(--border-color);
    display: flex;
    justify-content: space-around;
    padding: 10px 0;
    z-index: 100;
}

#bottom-nav.hidden {
    display: none;
}

.nav-item {
    background: none;
    border: none;
    display: flex;
    flex-direction: column;
    align-items: center;
    color: var(--text-light);
    cursor: pointer;
    font-size: 0.9rem;
    font-weight: bold;
}

.nav-item .icon {
    font-size: 1.5rem;
    margin-bottom: 4px;
}

.nav-item .label {
    font-size: 0.9rem;
}

.nav-item.active {
    color: var(--secondary-color);
}

/* View Control */
.view {
    display: none;
    flex-direction: column;
    flex-grow: 1;
    animation: fadeIn 0.3s ease;
}

.view.active {
    display: flex;
}

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

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

/* Typography & Titles */
h1,
h2 {
    color: var(--text-main);
    margin-bottom: 20px;
    text-align: center;
}

/*  Style Buttons */
.btn-primary,
.btn-secondary,
.btn-wrong {
    color: white;
    border: none;
    border-radius: 14px;
    padding: 12px 18px;
    font-size: 1.1rem;
    font-weight: 800;
    cursor: pointer;
    transition: all 0.1s ease;
    text-transform: uppercase;
    width: 100%;
    margin-top: auto;
    /* Push to bottom */
    display: flex;
    justify-content: center;
    align-items: center;
}

.btn-primary:active,
.btn-secondary:active,
.btn-wrong:active {
    transform: translateY(4px);
}

.btn-primary {
    background-color: var(--primary-color);
    box-shadow: 0 4px 0 var(--primary-shadow);
}

.btn-primary:active {
    box-shadow: 0 0 0 var(--primary-shadow);
}

.btn-secondary {
    background-color: var(--secondary-color);
    box-shadow: 0 4px 0 var(--secondary-shadow);
}

.btn-secondary:active {
    box-shadow: 0 0 0 var(--secondary-shadow);
}

.btn-wrong {
    background-color: var(--wrong-red);
    box-shadow: 0 4px 0 var(--wrong-shadow);
}

.btn-wrong:active {
    box-shadow: 0 0 0 var(--wrong-shadow);
}

/* Chapter & Module layout */
.chapter-card {
    border: 2px solid var(--border-color);
    border-radius: 20px;
    padding: 20px;
    margin-bottom: 24px;
    background-color: var(--card-bg);
    transition: background-color 0.3s ease, border-color 0.3s ease;
}

.chapter-card.chapter-completed {
    background-color: #d8ffb8;
    border-color: var(--primary-color);
}

.chapter-card.chapter-locked {
    opacity: 0.6;
    background-color: #f5f5f5;
    border-color: #ccc;
    cursor: not-allowed;
}

.chapter-card.chapter-locked .chapter-header {
    color: #999;
}

.chapter-header {
    display: flex;
    justify-content: space-between;
    align-items: center;
    cursor: pointer;
    font-size: 1.4rem;
    color: var(--text-main);
    margin: 0;
    user-select: none;
}

.chapter-card:not(.closed) .chapter-header {
    margin-bottom: 15px;
}

.chapter-card.closed .module-buttons {
    display: none;
}

.toggle-icon {
    font-size: 1.2rem;
    color: var(--text-light);
}

.chapter-card h2 {
    text-align: left;
    font-size: 1.4rem;
    margin-bottom: 20px;
    color: var(--text-main);
}

.module-buttons {
    display: flex;
    flex-direction: column;
    gap: 16px;
}

/* Settings Overlay */
/* Settings Overlay & Modals */
#settings-overlay,
#confirm-overlay {
    position: fixed;
    top: 0;
    left: 0;
    right: 0;
    bottom: 0;
    background: rgba(0, 0, 0, 0.5);
    display: flex;
    justify-content: center;
    align-items: center;
    z-index: 1000;
}

#settings-overlay.hidden,
#confirm-overlay.hidden {
    display: none;
}

.settings-modal {
    background: white;
    padding: 30px;
    border-radius: 20px;
    width: 90%;
    max-width: 400px;
    box-shadow: 0 10px 25px rgba(0, 0, 0, 0.1);
}

.flex-col-center {
    display: flex;
    flex-direction: column;
    align-items: center;
}

.setting-row {
    display: flex;
    justify-content: space-between;
    align-items: center;
    margin-bottom: 20px;
    font-weight: bold;
    color: var(--text-main);
}

/* Custom CSS Toggle Switch */
.toggle-switch {
    position: relative;
    display: inline-block;
    width: 50px;
    height: 28px;
}

.toggle-switch input {
    opacity: 0;
    width: 0;
    height: 0;
}

.slider {
    position: absolute;
    cursor: pointer;
    top: 0;
    left: 0;
    right: 0;
    bottom: 0;
    background-color: var(--border-color);
    transition: .4s;
    border-radius: 34px;
}

.slider:before {
    position: absolute;
    content: "";
    height: 20px;
    width: 20px;
    left: 4px;
    bottom: 4px;
    background-color: white;
    transition: .4s;
    border-radius: 50%;
}

input:checked+.slider {
    background-color: var(--primary-color);
}

input:checked+.slider:before {
    transform: translateX(22px);
}

/* Japanese Text Display Options */
/* Hide Furigana if disabled */
body.hide-furigana rt {
    display: none;
}

/* Hide Romaji if disabled */
body.hide-romaji .romaji-label {
    display: none;
}

/* General Japanese Text Styling */
.jap-word {
    display: inline-flex;
    flex-direction: column;
    align-items: center;
    margin: 0 5px;
    position: relative;
}

ruby {
    font-size: 1.5rem;
    font-weight: 700;
    ruby-align: center;
}

rt {
    font-size: 0.75rem;
    color: var(--text-light);
    font-weight: normal;
}

.romaji-label {
    font-size: 0.8rem;
    color: var(--secondary-color);
    margin-top: 2px;
}

/* Speaker Icon */
.btn-speaker {
    background: none;
    border: none;
    font-size: 1.5rem;
    cursor: pointer;
    color: var(--secondary-color);
    transition: transform 0.2s ease;
    position: absolute;
    left: 100%;
    top: 50%;
    transform: translateY(-50%);
    margin-left: 10px;
}

.btn-speaker:active {
    transform: translateY(-50%) scale(0.9);
}

/* Utilities */
.hidden {
    display: none !important;
}

/* Exercise UI (Vocab / Grammar / Chat) */
.exercise-container {
    display: flex;
    flex-direction: column;
    flex-grow: 1;
    padding-bottom: 80px;
    /* Space for feedback bar */
}

.question-header {
    font-size: 1.5rem;
    font-weight: 800;
    margin-bottom: 20px;
    text-align: center;
}

.big-question-word {
    font-size: 4.5rem;
    font-weight: bold;
    text-align: center;
    margin: 20px 0 40px 0;
    color: var(--primary-color);
}

/* Intro List */
.intro-list {
    display: flex;
    flex-direction: column;
    gap: 10px;
}

.intro-item {
    display: flex;
    justify-content: space-between;
    align-items: center;
    padding: 15px;
    background: white;
    border: 2px solid var(--border-color);
    border-radius: 16px;
}

.intro-german {
    font-weight: bold;
    width: 45%;
}

.intro-jap {
    width: 50%;
    text-align: right;
    padding-right: 40px;
}

/* Options Grid (Singlechoice) */
.options-grid {
    display: grid;
    grid-template-columns: 1fr;
    gap: 10px;
    margin-bottom: 20px;
}

.option-btn {
    background: var(--bg-color);
    border: 2px solid var(--border-color);
    border-radius: 16px;
    padding: 15px;
    font-size: 1.2rem;
    cursor: pointer;
    box-shadow: 0 4px 0 var(--border-color);
    color: var(--text-main);
    transition: all 0.1s;
    display: flex;
    flex-direction: column;
    align-items: center;
}

.option-btn:active {
    transform: translateY(4px);
    box-shadow: 0 0 0 var(--border-color);
}

.option-btn.selected {
    border-color: var(--secondary-color);
    background: #e1f4fc;
}

.option-btn.correct,
.matching-btn.correct {
    border-color: var(--primary-color);
    background: #d8ffb8;
    color: var(--primary-color);
    pointer-events: none;
}

.option-btn.wrong,
.matching-btn.wrong {
    border-color: var(--wrong-red);
    background: #ffdbdb;
    color: var(--wrong-red);
}

.option-btn.disabled {
    pointer-events: none;
}

/* Matching Grid */
.matching-grid {
    display: grid;
    grid-template-columns: 1fr 1fr;
    gap: 15px;
}

.matching-btn {
    background: var(--bg-color);
    border: 2px solid var(--border-color);
    border-radius: 12px;
    padding: 15px 10px;
    text-align: center;
    cursor: pointer;
    box-shadow: 0 4px 0 var(--border-color);
    font-weight: bold;
    display: flex;
    flex-direction: column;
    align-items: center;
    justify-content: center;
    min-height: 80px;
}

.matching-btn.selected {
    border-color: var(--secondary-color);
    background: #e1f4fc;
}

.matching-btn.disabled {
    opacity: 0.5;
    pointer-events: none;
}

/* Big Speaker */
.big-speaker-btn {
    background: var(--secondary-color);
    color: white;
    border: none;
    border-radius: 50%;
    width: 100px;
    height: 100px;
    font-size: 3rem;
    margin: 0 auto 30px auto;
    display: flex;
    align-items: center;
    justify-content: center;
    cursor: pointer;
    box-shadow: 0 6px 0 var(--secondary-shadow);
}

.big-speaker-btn:active {
    transform: translateY(6px);
    box-shadow: 0 0 0 var(--secondary-shadow);
}

/* Feedback Bar */
#feedback-bar {
    position: fixed;
    bottom: -150px;
    left: 50%;
    transform: translateX(-50%);
    width: 100%;
    max-width: 600px;
    padding: 20px;
    background: white;
    border-top: 2px solid var(--border-color);
    display: flex;
    justify-content: space-between;
    align-items: center;
    transition: bottom 0.3s cubic-bezier(0.175, 0.885, 0.32, 1.275);
    z-index: 100;
}

#feedback-bar.show {
    bottom: 0;
}

#feedback-bar.correct {
    background: #d8ffb8;
    border-color: var(--primary-color);
}

#feedback-bar.correct #feedback-msg {
    color: var(--primary-shadow);
}

#feedback-bar.wrong {
    background: #ffdbdb;
    border-color: var(--wrong-red);
}

#feedback-bar.wrong #feedback-msg {
    color: var(--wrong-shadow);
}

#feedback-content {
    display: flex;
    align-items: center;
    gap: 10px;
}

#feedback-icon {
    font-size: 2rem;
}

#feedback-msg {
    font-weight: 900;
    font-size: 1.4rem;
}

@media (min-width: 600px) {
    #feedback-bar {
        border-radius: 20px 20px 0 0;
        border: 2px solid var(--border-color);
        border-bottom: none;
    }

    #feedback-bar.correct {
        border-color: var(--primary-color);
    }

    #feedback-bar.wrong {
        border-color: var(--wrong-red);
    }
}

/* Grammar Explanation Screen */
.grammar-explanation {
    background: white;
    padding: 20px;
    border-radius: 16px;
    border: 2px solid var(--border-color);
    margin-bottom: 20px;
    line-height: 1.6;
}

.grammar-example {
    margin-top: 15px;
    padding: 15px;
    background: #f7f7f7;
    border-radius: 12px;
    border-left: 4px solid var(--secondary-color);
}

.grammar-example-jp {
    font-size: 1.2rem;
    font-weight: bold;
    margin-bottom: 5px;
    display: flex;
    align-items: center;
}

/* Grammar Puzzle */
.puzzle-question {
    font-size: 1.1rem;
    font-weight: bold;
    text-align: center;
    margin-bottom: 15px;
    color: var(--text-main);
}

.puzzle-target-area {
    min-height: 55px;
    border-bottom: 3px solid var(--border-color);
    margin-bottom: 20px;
    display: flex;
    flex-wrap: wrap;
    align-items: flex-end;
    gap: 6px;
    padding-bottom: 5px;
}

.puzzle-source-area {
    display: flex;
    flex-wrap: wrap;
    justify-content: center;
    gap: 6px;
    min-height: 80px;
}

.puzzle-block {
    background: white;
    border: 2px solid var(--border-color);
    border-radius: 10px;
    padding: 8px 12px;
    font-size: 1.1rem;
    font-weight: bold;
    cursor: pointer;
    box-shadow: 0 4px 0 var(--border-color);
    color: var(--text-main);
    display: flex;
    flex-direction: column;
    align-items: center;
    transition: transform 0.1s;
    user-select: none;
}

.puzzle-block:active {
    transform: translateY(4px);
    box-shadow: 0 0 0 var(--border-color);
}

.puzzle-block.hidden-block {
    visibility: hidden;
    /* Behält den Platz im Source-Grid */
}

/* Chat Module */
#chat-interaction-area {
    min-height: 200px;
    /* Verhindert das Kollabieren des Layouts beim "Leeren" */
    display: flex;
    flex-direction: column;
    justify-content: flex-end;
}

.chat-history {
    flex-grow: 1;
    overflow-y: auto;
    display: flex;
    flex-direction: column;
    gap: 10px;
    padding: 8px 10px;
    margin-bottom: 15px;
    max-height: 52vh;
    border: 2px solid var(--border-color);
    border-radius: 12px;
    background-color: white;
}

.chat-bubble {
    max-width: 90%;
    padding: 10px 14px;
    border-radius: 18px;
    font-size: 1rem;
    position: relative;
    box-shadow: 0 4px 0 rgba(0, 0, 0, 0.05);
    display: flex;
    flex-wrap: wrap;
    align-items: center;
}

.chat-partner {
    align-self: flex-start;
    background-color: #f7f7f7;
    border-bottom-left-radius: 4px;
    border: 2px solid var(--border-color);
}

.chat-user {
    align-self: flex-end;
    background-color: var(--secondary-color);
    color: white;
    border-bottom-right-radius: 4px;
}

.chat-user .romaji-label,
.chat-user rt {
    color: #e0f6ff;
}

.chat-partner-name {
    width: 100%;
    font-weight: 800;
    font-size: 0.9rem;
    margin-bottom: 5px;
    color: var(--text-light);
}

/* Typing Indicator Animation */
.typing-bubble {
    padding: 10px 16px;
}

.typing-indicator {
    display: flex;
    align-items: center;
    gap: 4px;
    padding: 0px 4px;
}

.typing-dot {
    width: 8px;
    height: 8px;
    background-color: var(--text-light);
    border-radius: 50%;
    animation: typingBounce 1.4s infinite ease-in-out both;
}

.typing-dot:nth-child(1) {
    animation-delay: -0.32s;
}

.typing-dot:nth-child(2) {
    animation-delay: -0.16s;
}

.typing-dot:nth-child(3) {
    animation-delay: 0s;
}

@keyframes typingBounce {

    0%,
    80%,
    100% {
        transform: scale(0);
        opacity: 0.4;
    }

    40% {
        transform: scale(1);
        opacity: 1;
    }
}

/* Alphabet View Layout & Tabs */
.alpha-tab-bar {
    display: flex;
    justify-content: space-between;
    background-color: var(--border-color);
    border-radius: 12px;
    padding: 4px;
    margin-bottom: 20px;
}

.alpha-tab {
    flex: 1;
    background: transparent;
    border: none;
    padding: 10px 0;
    font-weight: bold;
    color: var(--text-light);
    border-radius: 8px;
    cursor: pointer;
    transition: all 0.2s ease;
}

.alpha-tab.active {
    background-color: white;
    color: var(--primary-color);
    box-shadow: 0 2px 5px rgba(0, 0, 0, 0.1);
}

.alpha-chart-grid {
    display: grid;
    grid-template-columns: repeat(5, 1fr);
    gap: 8px;
    margin-bottom: 30px;
}

.alpha-char {
    background-color: white;
    border: 2px solid var(--border-color);
    border-radius: 10px;
    padding: 10px 0;
    text-align: center;
    cursor: pointer;
    transition: transform 0.1s;
}

.alpha-char:active {
    transform: scale(0.95);
}

.alpha-char .kana {
    font-size: 1.5rem;
    font-weight: bold;
    color: var(--text-main);
}

.alpha-char .rom {
    font-size: 0.8rem;
    color: var(--text-light);
    margin-top: 4px;
}

.alpha-empty {
    visibility: hidden;
}

.alpha-section-title {
    margin-top: 20px;
    margin-bottom: 10px;
    color: var(--text-main);
    font-size: 1.2rem;
    border-bottom: 2px solid var(--border-color);
    padding-bottom: 5px;
}