/* ── Base ─────────────────────────────────────────────────────────────────── */
*, *::before, *::after {
    box-sizing: border-box;
}

body {
    background-color: #0d0d0d;
    color: #e0e0e0;
    font-family: "Segoe UI", Arial, sans-serif;
    margin: 0;
    padding: 1.5rem;
    max-width: 860px;
    margin-inline: auto;
}

h1 {
    color: #00e5ff;
    margin-bottom: 0.25rem;
}

h2 {
    color: #00e5ff;
    font-size: 1.1rem;
    margin-top: 0;
}

h3 {
    color: #80deea;
    margin: 0.5rem 0;
}

p, label {
    color: #c0c0c0;
}

/* ── Cards (step containers) ─────────────────────────────────────────────── */
.card {
    background: #1a1a2e;
    border: 1px solid #00e5ff33;
    border-radius: 8px;
    padding: 1.25rem 1.5rem;
    margin-bottom: 1.5rem;
}

/* ── File upload ─────────────────────────────────────────────────────────── */
.file-label {
    display: inline-block;
    cursor: pointer;
}

.file-label-text {
    display: inline-block;
    background: #00e5ff;
    color: #0d0d0d;
    font-weight: 600;
    padding: 0.45rem 1rem;
    border-radius: 5px;
    margin-right: 0.5rem;
    transition: background 0.2s;
}

.file-label:hover .file-label-text {
    background: #00bcd4;
}

#pdf_upload {
    /* visually hidden but accessible */
    position: absolute;
    width: 1px;
    height: 1px;
    opacity: 0;
    overflow: hidden;
}

#upload-status {
    margin-top: 0.6rem;
    font-size: 0.9rem;
    min-height: 1.2em;
    color: #00e5ff;
}

/* ── Loading spinner ─────────────────────────────────────────────────────── */
.spinner {
    width: 28px;
    height: 28px;
    border: 4px solid #00e5ff44;
    border-top-color: #00e5ff;
    border-radius: 50%;
    animation: spin 0.8s linear infinite;
    margin-top: 0.5rem;
}

@keyframes spin {
    to { transform: rotate(360deg); }
}

/* ── Chapter list ────────────────────────────────────────────────────────── */
.chapter-list {
    display: flex;
    flex-direction: column;
    gap: 0.5rem;
    max-height: 320px;
    overflow-y: auto;
    padding-right: 4px;
}

.chapter-item {
    display: flex;
    justify-content: space-between;
    align-items: center;
    background: #0f3460;
    border: 1px solid #00e5ff33;
    border-radius: 6px;
    padding: 0.6rem 1rem;
    cursor: pointer;
    transition: background 0.15s, border-color 0.15s;
    gap: 1rem;
}

.chapter-item:hover {
    background: #16213e;
    border-color: #00e5ff88;
}

.chapter-item.selected {
    background: #004d60;
    border-color: #00e5ff;
    outline: 2px solid #00e5ff;
}

.chapter-title {
    color: #e0e0e0;
    font-size: 0.95rem;
    flex: 1;
}

.chapter-pages {
    color: #80deea;
    font-size: 0.8rem;
    white-space: nowrap;
}

/* ── Text preview ────────────────────────────────────────────────────────── */
.text-preview {
    background: #111;
    border: 1px solid #333;
    border-radius: 6px;
    padding: 1rem;
    max-height: 220px;
    overflow-y: auto;
    font-size: 0.85rem;
    line-height: 1.6;
    color: #d0d0d0;
    white-space: pre-wrap;
    word-break: break-word;
    margin-bottom: 1rem;
}

/* ── Buttons ─────────────────────────────────────────────────────────────── */
button {
    background: #00e5ff;
    color: #0d0d0d;
    border: none;
    border-radius: 5px;
    padding: 0.5rem 1.25rem;
    font-weight: 600;
    font-size: 0.95rem;
    cursor: pointer;
    transition: background 0.2s, opacity 0.2s;
}

button:hover:not(:disabled) {
    background: #00bcd4;
}

button:disabled {
    opacity: 0.4;
    cursor: not-allowed;
}

/* ── Selected info banner ────────────────────────────────────────────────── */
.selected-info {
    margin-top: 0.75rem;
    background: #00402a;
    border: 1px solid #00e676;
    border-radius: 5px;
    padding: 0.5rem 0.9rem;
    color: #00e676;
    font-size: 0.9rem;
}

/* ── Quiz section ────────────────────────────────────────────────────────── */
.question-container {
    display: flex;
    flex-direction: column;
    gap: 1rem;
    margin-bottom: 1rem;
}

.question {
    background: #0f3460;
    border: 1px solid #00e5ff22;
    border-radius: 6px;
    padding: 0.9rem 1.1rem;
}

.question p {
    margin: 0.4rem 0 0.7rem;
}

.question label {
    display: block;
    margin: 0.3rem 0;
    cursor: pointer;
}

.question label:hover {
    color: #00e5ff;
}

#quiz-result {
    margin-top: 0.6rem;
    font-weight: 600;
    color: #00e5ff;
}