:root {
    --bg-overlay: rgba(44, 24, 16, 0.6);
    --bg-modal: #FDFBF7;
    --bg-panel: #FFFFFF;
    --text-primary: #2C1810;
    --text-secondary: #6D5E57;
    --brand-primary: #8D6E63;
    --brand-dark: #5D4037;
    --brand-accent: #A1887F;
    --border-color: #D7CCC8;
    --danger: #D32F2F;
    --success: #388E3C;
    --link: #0645AD;
    --input-bg: #FFFFFF;
    --paper: #f7f3e9;
    --ink: #222;
    --font-serif: "Playfair Display", Georgia, serif;
    --font-sans: "Lato", Arial, sans-serif;
    --white: #F9FAFB;
}


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


body {
    overflow-y: auto;
    background-color: var(--white);
    font-family: Arial, sans-serif;
    padding: 80px 0 0;
    display: flex;
    flex-direction: column;
    padding-bottom: 40px;
    min-height: 100vh;
}

main {
    flex: 1
}

.hidden {
    display: none !important
}

.centre {
    position: fixed;
    top: 50%;
    left: 50%;
    transform: translate(-50%, -50%);
}

.solid-line {
    border: 0;
    border-top: 2px solid #ccc;
    margin: 20px 0;
}

.section {
    max-width: 1100px;

}

.skill-container {
    width: 90%;
    height: 90vh;
    margin: auto;
    padding: 20px;
}

#topicsGrid, #categories, #titles {
    flex: 1;
    display: grid;
    grid-template-columns: repeat(auto-fill, minmax(238px, 1fr));
    gap: 12px;
    align-items: stretch;
    grid-auto-rows: 1fr;
}
.page-header {
    display: flex;
    justify-content: space-between;
    align-items: center;
    margin-bottom: 30px;
    flex-wrap: wrap;
    color: var(--ink);
}

.section-header {
    display: flex;
    justify-content: space-between;
    align-items: center;
    margin-top: 20px;
}

.section-header h3,
.page-title {
    font-size: 28px;
    font-weight: bold;
    color: var(--text-primary);
    font-family: var(--font-serif);
    margin: 0;
}

.section-header h3 {
    font-size: 22px;
}

.vb-rules {
    margin: 10px auto 20px;
    height: 6px;
    border-top: 1px solid #c8c2b3;
    border-bottom: 1px solid #c8c2b3;
    background: repeating-linear-gradient(90deg, transparent, transparent 14px, rgba(0, 0, 0, .08) 14px, rgba(0, 0, 0, .08) 16px);
}

.lesson-progress {
    position: absolute;
    bottom: 20px;
    left: 20px;
    color: var(--text-secondary);
    font-size: 0.85rem;
}

.category-item,
.title-item,
.mode-item,
.lesson-item {
    padding: 14px;
    border-radius: 14px;
    font-variant: small-caps;
    letter-spacing: .06em;
    transition: background .15s ease, border-color .15s ease;
    cursor: pointer;
    display: flex;
    flex-direction: column;
    width: 238px;
    margin: 8px;
    background: var(--white);
    border: 1px solid #c8c2b3;
    color: #222;
    box-shadow:
        0 4px 6px -1px rgba(0, 0, 0, 0.1),
        0 -1px 10px rgba(0, 0, 0, 0.05),
        4px 0 15px rgba(0, 0, 0, 0.05),
        -4px 0 15px rgba(0, 0, 0, 0.05);
}

.category-item:hover,
.title-item:hover,
.mode-item:hover,
.lesson-item:hover {
    background: #f0eadc;
    border-color: #9a917c;
    transform: translateY(-2px);
}

.category-item.active,
.title-item.active,
.lesson-item.active .mode-item.active {
    background: #f0eadc;
    border-color: #9a917c;
}

.category-item.completed,
.title-item.completed,
.step-card.completed,
.lesson-item.completed {
    position: relative;
    background: #e9f7ec;
    color: black;
    border-color: #8fbf9b;
}

.category-item.completed::after,
.title-item.completed::after,
.step-card.completed::after,
.lesson-item.completed::after {
    content: "✓";
    position: absolute;
    top: -8px;
    left: -8px;
    background: #8fbf9b;
    color: #fff;
    width: 18px;
    height: 18px;
    border-radius: 50%;
    display: grid;
    place-items: center;
    font-size: 12px;
}

.premium {
  color: #8c826c;
  cursor: not-allowed;
  position: relative;
  overflow: hidden;
  pointer-events: none;
  background: #fffefc;
  border-color: #d6d0c4;
  background-image: repeating-linear-gradient(-45deg,
      transparent,
      transparent 4px,
      rgba(190, 179, 150, 0.15) 4px,
      rgba(190, 179, 150, 0.15) 5px);
}

.premium::before {
  content: '';
  position: absolute;
  top: 0;
  right: 0;
  border-width: 0 32px 32px 0;
  border-style: solid;
  border-color: transparent #b0996d transparent transparent;
  transition: border-color 0.2s;
}

.premium::after {
  content: "★";
  position: absolute;
  top: 4px;
  right: 4px;
  font-size: 11px;
  color: #fffef7;
  transform: rotate(45deg);
}

#group-container {
    display: flex;
    gap: 15px;
    align-items: flex-start;
}

.continue-restart-popup {
    position: fixed;
    top: 50%;
    left: 50%;
    transform: translate(-50%, -50%);
    display: flex;
    flex-direction: column;
    align-items: center;
    justify-content: center;
    box-sizing: border-box;
    padding: 20px;
    background: linear-gradient(180deg, #ffffff 0%, #f9f9f9 100%);
    border: 1px solid #ddd;
    border-radius: 16px;
    box-shadow: 0 8px 24px rgba(0, 0, 0, 0.12);
    transition: transform 0.2s ease, width 0.3s ease, height 0.3s ease;
    z-index: 9999;

}

.button-row {
    display: flex;
    gap: 15px;
    margin-top: 15px;
    justify-content: space-between;
}

.btn,
.choice-btn {
    padding: 10px 18px;
    cursor: pointer;
    font-size: 16px;
    background: var(--brand-dark);
    color: white;
    border-radius: 10px;
    border: none;
    font-family: var(--font-sans);
    font-weight: 600;
    transition: background 0.3s;
}

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

.close-button {
    position: absolute;
    top: 15px;
    right: 15px;
    font-size: 24px;
    background: none;
    border: none;
    color: var(--text-secondary);
    cursor: pointer;
}

.close-button:hover {
    color: var(--brand-dark);
}

#back-button {
    width: fit-content;
    color: white;
    background: var(--brand-dark);
}

#back-wrapper {
    flex: 0 0 auto;
}

.popup {
    position: fixed;
    top: 50%;
    left: 50%;
    transform: translate(-50%, -50%);
    width: 480px;
    height: auto;
    min-height: 550px;
    display: flex;
    flex-direction: column;
    align-items: center;
    box-sizing: border-box;
    padding: 30px;
    background: var(--bg-modal);
    border: 1px solid var(--border-color);
    border-radius: 20px;
    box-shadow: 0 10px 40px rgba(44, 24, 16, 0.2);
    z-index: 9997;
}


.mcq-options {
    display: grid;
    grid-template-columns: repeat(2, 1fr);
    gap: 12px;
    justify-items: center;
    margin-top: 10px;
    align-items: stretch;
    grid-auto-rows: 1fr;
}

.option-btn {
    padding: 14px;
    font-size: 0.85rem;
    font-family: var(--font-serif);
    background: var(--bg-panel);
    border: 1px solid var(--border-color);
    color: var(--text-primary);
    border-radius: 12px;
    cursor: pointer;
    min-width: 200px;
    text-align: center;
    transition: all 0.2s ease-in-out;
    box-shadow: 0 2px 5px rgba(44, 24, 16, 0.05);
}

.option-btn:hover {
    background: var(--brand-primary);
    border-color: var(--brand-primary);
    color: #FFFFFF;
    transform: translateY(-2px);
    box-shadow: 0 4px 12px rgba(93, 64, 55, 0.25);
}


.option-btn.correct {
    background: #E8F5E9;
    border: 1px solid var(--success);
    color: var(--success);
    font-weight: 600;
    box-shadow: none;
}

.option-btn.wrong {
    background: #FFEBEE;
    border: 1px solid var(--danger);
    color: var(--danger);
    font-weight: 600;
    box-shadow: none;
}


.config-btn {
    background: none;
    border: none;
    color: var(--text-secondary);
    cursor: pointer;
    padding: 8px;
    border-radius: 50%;
    transition: background 0.2s, color 0.2s;
    display: grid;
    place-items: center;
}

.config-btn:hover {
    background: rgba(141, 110, 99, 0.1);
    color: var(--brand-dark);
}

.settings-menu {
    position: absolute;
    top: 40px;
    left: 0;
    width: 220px;
    background: var(--bg-panel);
    border: 1px solid var(--border-color);
    border-radius: 12px;
    box-shadow: 0 4px 15px rgba(0, 0, 0, 0.1);
    padding: 10px;
    display: none;
    flex-direction: column;
    gap: 8px;
    z-index: 1000;
}

.settings-menu.visible {
    display: flex;
}

.settings-item {
    display: flex;
    align-items: center;
    gap: 10px;
    padding: 8px;
    border-radius: 8px;
    cursor: pointer;
    font-family: var(--font-sans);
    font-size: 0.7rem;
    color: var(--text-primary);
    transition: background 0.1s;
    user-select: none;
}

.settings-item:hover {
    background: var(--paper);
}

.settings-item input[type="checkbox"] {
    accent-color: var(--brand-primary);
    width: 16px;
    height: 16px;
    cursor: pointer;
}

.settings-icon {
    display: flex;
    align-items: center;
    color: var(--brand-primary);
}

#toast-container {
    position: fixed;
    bottom: 20px;
    right: 20px;
    z-index: 9999;
    display: flex;
    flex-direction: column;
    gap: 10px;
}

.toast {
    padding: 15px 20px;
    border-radius: 8px;
    color: #fff;
    font-family: sans-serif;
    opacity: 0;
    transform: translateY(20px);
    transition: all 0.3s ease-in-out;
    box-shadow: 0 4px 12px rgba(0, 0, 0, 0.2);
}

.toast.show {
    opacity: 1;
    transform: translateY(0);
}

.toast.info {
    background-color: #007bff;
}

.toast.success {
    background-color: #28a745;
}

.toast.error {
    background-color: #dc3545;
}

.blur {
    filter: blur(20px);
    pointer-events: none;
    user-select: none;
}


@media (max-width: 600px) {
    .mcq-options {
        grid-template-columns: 1fr !important;
    }

    .option-btn {
        width: fit-content;
    }

    .continue-restart-popup {
        width: 90%;
    }

    .category-item,
    .title-item,
    .mode-item,
    .lesson-item {
        width: 90%;
    }

    .popup {
        width: 100%;
    }

    #group-container {
        flex-direction: column;
    }
}