/* TEMEL STİLLER ve SİBER GÜVENLİK TEMASI */
:root {
    --bg-color: #1a1a1a;
    --sidebar-bg: #101010;
    --editor-bg: #1a1a1a;
    --console-bg: #101010;
    --text-color: #e0e0e0;
    --text-color-light: #9a9a9a;
    --border-color: #333333;
    --accent-color: #00ff9c;
    --accent-text: #101010;
    --button-bg: #00ff9c;
    --button-text: #101010;
    --button-hover: #4dffbd;
    --danger-color: #ff8a80;
    --font-family: 'Roboto Mono', 'Courier New', Courier, monospace;
}

body, html {
    margin: 0;
    padding: 0;
    height: 100%;
    font-family: var(--font-family);
    background-color: var(--bg-color);
    color: var(--text-color);
    font-size: 14px;
    overflow: hidden;
}

/* ANA LAYOUT */
.container {
    display: flex;
    height: 100vh;
}

/* 1. SÜTUN: Navigasyon/Kenar Çubuğu */
.sidebar {
    width: 250px;
    background-color: var(--sidebar-bg);
    border-right: 2px solid var(--border-color);
    padding: 20px;
    box-sizing: border-box;
    display: flex;
    flex-direction: column;
    flex-shrink: 0;
    overflow-y: auto;
}
.sidebar h2 {
    font-size: 20px;
    margin-top: 0;
    border-bottom: 1px solid var(--border-color);
    padding-bottom: 10px;
    color: var(--accent-color);
    text-shadow: 0 0 5px rgba(0, 255, 156, 0.5);
}

#reset-progress-button {
    width: 100%;
    margin-top: 15px;
    margin-bottom: 10px;
}
.sidebar nav {
    width: 100%;
}
#lesson-tree-container {
    list-style: none;
    padding: 0;
    margin: 0;
}
.topic-header {
    font-size: 16px;
    font-weight: 700;
    color: var(--accent-color);
    margin-top: 20px;
    margin-bottom: 10px;
    padding-bottom: 5px;
    border-bottom: 1px solid var(--border-color);
    cursor: pointer;
    position: relative;
    transition: color 0.2s ease;
}
.topic-header:hover {
    color: var(--button-hover);
}
.topic-header:first-child {
    margin-top: 0;
}
.topic-header::before {
    content: '+';
    position: absolute;
    right: 5px;
    top: 0;
    font-size: 20px;
    color: var(--text-color-light);
}
.topic-header.active::before {
    content: '−';
}
.exercise-list {
    list-style: none;
    padding-left: 10px;
    margin: 0;
    max-height: 0;
    overflow: hidden;
    transition: max-height 0.3s ease-out;
}
.exercise-list.expanded {
    max-height: 1000px; /* İçeriğin sığabileceği kadar büyük bir değer */
    transition: max-height 0.5s ease-in;
}
.exercise-item {
    padding: 10px 15px;
    cursor: pointer;
    border-radius: 4px;
    margin-bottom: 5px;
    transition: all 0.2s ease-in-out;
    border-left: 3px solid transparent;
    color: var(--text-color-light);
    font-size: 13px;
    position: relative;
}
.exercise-item:hover {
    background-color: #2a2a2a;
    color: var(--text-color);
    border-left: 3px solid var(--accent-color);
}
.exercise-item.active {
    background-color: var(--accent-color);
    color: var(--accent-text);
    font-weight: 700;
    border-left: 3px solid var(--accent-color);
}
.exercise-item.completed {
    color: var(--text-color-light);
}
.exercise-item.completed::after {
    content: '✓';
    color: var(--accent-color);
    font-weight: 700;
    position: absolute;
    right: 15px;
    top: 50%;
    transform: translateY(-50%);
}
.exercise-item.completed.active {
    color: var(--accent-text);
}


/* 2. SÜTUN: İçerik Alanı */
.content {
    flex-grow: 1;
    padding: 30px;
    overflow-y: auto;
    box-sizing: border-box;
}
.content h1 {
    margin-top: 0;
    font-size: 28px;
    border-bottom: 1px solid var(--border-color);
    padding-bottom: 15px;
    color: var(--accent-color);
}
.content p {
    line-height: 1.8;
    font-size: 16px;
}
.content code {
    background-color: var(--console-bg);
    padding: 3px 6px;
    border-radius: 4px;
    font-size: 0.9em;
    color: var(--accent-color);
    border: 1px solid var(--border-color);
}
.content pre {
    background-color: var(--console-bg);
    padding: 15px;
    border-radius: 4px;
    border: 1px solid var(--border-color);
    font-size: 15px;
    overflow-x: auto;
}
.content .challenge {
    background-color: var(--sidebar-bg);
    border: 1px solid var(--border-color);
    border-left: 4px solid var(--accent-color);
    padding: 20px;
    border-radius: 4px;
    margin-top: 30px;
}
.content .challenge h3 {
    margin-top: 0;
}
#challenge-hint {
    display: none;
    margin-top: 20px;
    padding: 15px;
    background-color: var(--console-bg);
    border: 1px solid var(--border-color);
    border-left: 3px solid var(--text-color-light);
    color: var(--text-color-light);
    border-radius: 4px;
    font-style: italic;
}
#challenge-hint code {
    color: var(--accent-color);
    font-style: normal;
}

#ask-gemini-button {
    display: inline-block; /* Buton gibi davranması için */
    margin-top: 30px; /* Üstteki meydan okuma kutusundan boşluk */
    text-decoration: none; /* Alt çizgiyi kaldır */
    /* Opsiyonel: Farklı bir görünüm için */
    background-color: var(--sidebar-bg);
    color: var(--text-color-light);
    border: 1px solid var(--border-color);
}
#ask-gemini-button:hover {
    background-color: #2a2a2a;
    color: var(--text-color);
    border-color: var(--accent-color);
}
.external-icon {
    font-size: 0.8em; /* İkonu biraz küçült */
    margin-left: 5px;
    display: inline-block;
    transform: translateY(-1px); /* Dikey hizalama */
}

/* 3. SÜTUN: Kod Editörü ve Konsol */
.code-area {
    width: 50%;
    max-width: 50%;
    background-color: var(--editor-bg);
    border-left: 2px solid var(--border-color);
    flex-shrink: 0;
    height: 100%;
    /* YENİ: Mutlak konumlandırma için referans */
    position: relative;
    /* display: grid/flex kaldırıldı */
    overflow: hidden; /* Taşmayı engelle */
}
.editor-pane {
    /* YENİ: Mutlak Konumlandırma */
    position: absolute;
    top: 0;
    left: 0;
    right: 0;
    /* YENİ: Yüksekliği hesapla (Konsolun border'ını çıkar) */
    height: calc(60% - 2px); /* Konsol %40 alacak, bu %60 - border */
    /* İsteğe bağlı minimum yükseklik */
    min-height: 350px;

    /* İç düzen için flex kalmalı */
    display: flex;
    flex-direction: column;
    overflow: hidden;
}
.editor-header {
    padding: 10px 15px;
    background-color: var(--sidebar-bg);
    border-bottom: 1px solid var(--border-color);
    display: flex;
    justify-content: space-between;
    align-items: center;
    font-weight: 700;
    flex-shrink: 0;
}
.editor-header span {
    color: #4CAF50;
}
#code-editor {
    width: 100%;
    flex-grow: 1;
    overflow: hidden;
}
.editor-controls {
    display: flex;
    align-items: center;
    gap: 8px;
    flex-shrink: 0;
}

/* Tüm Utility Butonlar için Temel */
.utility-button {
    padding: 8px 12px;
    border-radius: 4px;
    cursor: pointer;
    font-weight: 700;
    font-size: 14px;
    transition: all 0.2s ease;
    font-family: var(--font-family);
    white-space: nowrap;
    border: 1px solid transparent;
}

/* İkon Buton Stili */
.icon-button {
    font-size: 18px;
    padding: 6px 8px;
    line-height: 1;
    background-color: transparent;
    color: var(--text-color-light);
    border: none;
}
.icon-button:hover {
    color: var(--accent-color);
    background-color: rgba(0, 255, 156, 0.1);
}
.icon-button.danger {
    color: var(--danger-color);
}
.icon-button.danger:hover {
    background-color: rgba(255, 138, 128, 0.1);
}

/* Metinli Utility Butonlar (Sonraki Alıştırma) */
.utility-button.primary {
    background-color: var(--accent-color);
    color: var(--accent-text);
    border: 1px solid var(--accent-color);
}
.utility-button.primary:hover {
    background-color: var(--button-hover);
    border-color: var(--button-hover);
    box-shadow: 0 0 10px rgba(0, 255, 156, 0.5);
}

/* İlerlemeyi Sıfırla Butonu (Sidebar'da, metinli) */
#reset-progress-button.danger {
    border: 1px solid var(--danger-color);
    color: var(--danger-color);
    background-color: transparent;
}
#reset-progress-button.danger:hover {
    background-color: var(--danger-color);
    color: var(--accent-text);
    box-shadow: 0 0 10px rgba(255, 138, 128, 0.5);
}

/* Kodu Çalıştır Butonu */
#run-button {
    background-color: var(--button-bg);
    color: var(--button-text);
    padding: 8px 16px;
    border: none;
    border-radius: 4px;
    cursor: pointer;
    font-weight: 700;
    font-size: 14px;
    transition: all 0.2s ease;
    font-family: var(--font-family);
}
#run-button:hover {
    background-color: var(--button-hover);
    box-shadow: 0 0 10px rgba(0, 255, 156, 0.5);
}
#run-button:disabled {
    background-color: #555;
    color: #999;
    cursor: not-allowed;
    box-shadow: none;
}

/* Konsol/Test Paneli */
.console-pane {
    /* YENİ: Mutlak Konumlandırma */
    position: absolute;
    bottom: 0;
    left: 0;
    right: 0;
    height: 40%; /* Sabit yükseklik */

    /* İç düzen için flex kalmalı */
    display: flex;
    flex-direction: column;
    border-top: 2px solid var(--border-color);
    background-color: var(--console-bg);
    overflow: hidden; /* Taşmayı engelle */
}
.tab-header {
    display: flex;
    background-color: var(--sidebar-bg);
    border-bottom: 1px solid var(--border-color);
    flex-shrink: 0;
}
.tab-item {
    padding: 10px 15px;
    cursor: pointer;
    font-weight: 700;
    color: var(--text-color-light);
    border-bottom: 3px solid transparent;
    transition: all 0.2s ease;
}
.tab-item:hover {
    color: var(--text-color);
}
.tab-item.active {
    color: var(--accent-color);
    border-bottom: 3px solid var(--accent-color);
}
.tab-content {
    flex-grow: 1; /* Konsol pane içinde kalan alanı doldurur */
    position: relative;
    overflow: hidden;
}
.tab-pane {
    position: absolute;
    top: 0;
    left: 0;
    width: 100%;
    height: 100%;
    padding: 15px;
    box-sizing: border-box;
    font-family: var(--font-family);
    font-size: 15px;
    white-space: pre-wrap;
    word-wrap: break-word;
    overflow-y: auto;
    color: var(--text-color);
    opacity: 0;
    visibility: hidden;
    transition: opacity 0.3s ease, visibility 0.3s ease;
}
.tab-pane.active {
    opacity: 1;
    visibility: visible;
}
#console-output .error, #test-result-output .error {
    color: var(--danger-color);
}
#console-output .system, #test-result-output .system {
    color: var(--text-color-light);
    font-style: italic;
}
#test-result-output .success {
    color: var(--accent-color);
    font-weight: 700;
}
#test-result-output .failure {
    color: var(--danger-color);
    font-weight: 700;
}