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

:root {
    --primary-color: #4285f4;
    --secondary-color: #34a853;
    --danger-color: #ea4335;
    --text-color: #202124;
    --bg-color: #f8f9fa;
    --card-bg: #ffffff;
    --border-radius: 8px;
}

body {
    font-family: -apple-system, BlinkMacSystemFont, 'Segoe UI', 'Helvetica Neue', Arial, sans-serif;
    background-color: var(--bg-color);
    color: var(--text-color);
    line-height: 1.6;
}

#app {
    max-width: 800px;
    margin: 0 auto;
    min-height: 100vh;
    display: flex;
    flex-direction: column;
}

header {
    background-color: var(--primary-color);
    color: white;
    padding: 1rem;
    display: flex;
    justify-content: space-between;
    align-items: center;
}

header h1 {
    font-size: 1.5rem;
}

.icon-btn {
    background: none;
    border: none;
    font-size: 1.5rem;
    cursor: pointer;
    padding: 0.5rem;
}

main {
    flex: 1;
    padding: 1rem;
}

.page {
    display: none;
}

.page.active {
    display: block;
}

/* トップページ */
.home-buttons {
    display: flex;
    gap: .5rem;
}

.big-btn {
    flex: 1;
    padding: .5rem;
    font-size: .7rem;
    background-color: var(--primary-color);
    color: white;
    border: none;
    border-radius: var(--border-radius);
    cursor: pointer;
    transition: opacity 0.2s;
}

.big-btn:hover {
    opacity: 0.9;
}

.big-btn.secondary {
    background-color: var(--secondary-color);
}

/* 学習ページ */
.card-navigation {
    display: flex;
    justify-content: space-between;
    align-items: center;
    margin-bottom: 1rem;
}

.nav-btn {
    background-color: var(--primary-color);
    color: white;
    border: none;
    padding: 0.5rem 1rem;
    border-radius: var(--border-radius);
    cursor: pointer;
    font-size: 1.2rem;
}

.flash-card {
    background-color: var(--card-bg);
    border-radius: var(--border-radius);
    padding: 2rem;
    min-height: 400px;
    box-shadow: 0 2px 8px rgba(0,0,0,0.1);
    display: flex;
    flex-direction: column;
    justify-content: space-between;
    margin-bottom: 1rem;
}

.card-content {
    flex: 1;
}

.card-text {
    font-size: 1.5rem;
    margin-bottom: 1rem;
    white-space: pre-wrap;
}

.card-image-container img {
    max-width: 100%;
    cursor: pointer;
    border-radius: var(--border-radius);
    margin: 1rem 0;
}

.card-audio-container {
    margin: 1rem 0;
}

.audio-controls {
    display: flex;
    gap: 0.5rem;
}

.audio-controls button {
    padding: 0.5rem 1rem;
    background-color: var(--primary-color);
    color: white;
    border: none;
    border-radius: var(--border-radius);
    cursor: pointer;
}

.card-youtube-container iframe {
    width: 100%;
    height: 315px;
    border-radius: var(--border-radius);
    margin: 1rem 0;
}

.card-youtube-container iframe.audio-only {
    display: none;
    position: absolute;
    width: 0;
    height: 0;
    border: none;
}

.flip-btn {
    width: 100%;
    padding: 1rem;
    background-color: var(--secondary-color);
    color: white;
    border: none;
    border-radius: var(--border-radius);
    font-size: 1.1rem;
    cursor: pointer;
}

.review-schedule {
    background-color: var(--card-bg);
    padding: 1.5rem;
    border-radius: var(--border-radius);
    margin-bottom: 1rem;
}

.review-schedule.hidden {
    display: none;
}

.schedule-buttons {
    display: grid;
    grid-template-columns: repeat(3, 1fr);
    gap: 0.5rem;
    margin: 1rem 0;
}

.schedule-btn {
    padding: 0.75rem;
    background-color: var(--primary-color);
    color: white;
    border: none;
    border-radius: var(--border-radius);
    cursor: pointer;
}

.schedule-btn.auto {
    background-color: var(--secondary-color);
}

.custom-time {
    display: flex;
    gap: 0.5rem;
    margin-top: 1rem;
}

.custom-time input {
    flex: 1;
    padding: 0.75rem;
    border: 1px solid #ddd;
    border-radius: var(--border-radius);
    font-size: 1rem;
}

.custom-time button {
    padding: 0.75rem 1.5rem;
    background-color: var(--primary-color);
    color: white;
    border: none;
    border-radius: var(--border-radius);
    cursor: pointer;
}

.back-btn {
    width: 100%;
    padding: 1rem;
    background-color: #5f6368;
    color: white;
    border: none;
    border-radius: var(--border-radius);
    cursor: pointer;
}

/* 編集ページ */
.card-section {
    background-color: var(--card-bg);
    padding: 1.5rem;
    border-radius: var(--border-radius);
    margin-bottom: 1rem;
}

.card-section h3 {
    margin-bottom: 1rem;
}

.card-section textarea,
.card-section input[type="text"] {
    width: 100%;
    padding: 0.75rem;
    border: 1px solid #ddd;
    border-radius: var(--border-radius);
    font-size: 1rem;
    margin-bottom: 1rem;
    font-family: inherit;
}

.youtube-mode {
    display: flex;
    gap: 1rem;
    margin-bottom: 1rem;
}

.youtube-mode label {
    display: flex;
    align-items: center;
    gap: 0.5rem;
    cursor: pointer;
}

.youtube-mode input[type="radio"] {
    cursor: pointer;
}

.card-section textarea {
    min-height: 100px;
    resize: vertical;
}

.drop-zone {
    border: 2px dashed #ddd;
    border-radius: var(--border-radius);
    padding: 2rem;
    text-align: center;
    margin-bottom: 1rem;
    cursor: pointer;
    transition: background-color 0.2s;
}

.drop-zone.drag-over {
    background-color: #e8f0fe;
    border-color: var(--primary-color);
}

.drop-zone input[type="file"] {
    display: none;
}

.preview {
    margin-bottom: 1rem;
}

.preview img {
    max-width: 200px;
    border-radius: var(--border-radius);
    cursor: pointer;
}

.form-buttons {
    display: flex;
    gap: 0.5rem;
}

.submit-btn,
.cancel-btn,
.delete-btn {
    flex: 1;
    padding: 1rem;
    border: none;
    border-radius: var(--border-radius);
    font-size: 1rem;
    cursor: pointer;
}

.submit-btn {
    background-color: var(--primary-color);
    color: white;
}

.cancel-btn {
    background-color: #5f6368;
    color: white;
}

.delete-btn {
    background-color: var(--danger-color);
    color: white;
}

.delete-btn.hidden {
    display: none;
}

/* カード一覧 */
.card-list {
    display: flex;
    flex-direction: column;
    gap: 1rem;
    margin-bottom: 1rem;
}

.card-item {
    background-color: var(--card-bg);
    padding: 1rem;
    border-radius: var(--border-radius);
    box-shadow: 0 1px 3px rgba(0,0,0,0.1);
    cursor: pointer;
    transition: box-shadow 0.2s;
}

.card-item:hover {
    box-shadow: 0 2px 8px rgba(0,0,0,0.15);
}

.card-item-header {
    display: flex;
    justify-content: space-between;
    align-items: start;
    margin-bottom: 0.5rem;
}

.card-item-text {
    flex: 1;
    font-weight: 500;
}

.card-item-meta {
    font-size: 0.85rem;
    color: #5f6368;
}

.card-item-buttons {
    display: flex;
    gap: 0.5rem;
    margin-top: 0.5rem;
}

.card-item-buttons button {
    padding: 0.5rem 1rem;
    border: none;
    border-radius: var(--border-radius);
    cursor: pointer;
    font-size: 0.9rem;
}

.view-btn {
    background-color: var(--primary-color);
    color: white;
}

.edit-btn {
    background-color: var(--secondary-color);
    color: white;
}

/* モーダル */
.modal {
    display: none;
    position: fixed;
    top: 0;
    left: 0;
    width: 100%;
    height: 100%;
    background-color: rgba(0,0,0,0.8);
    z-index: 1000;
    justify-content: center;
    align-items: center;
}

.modal.active {
    display: flex;
}

.modal img {
    max-width: 90%;
    max-height: 90%;
}

/* レスポンシブ */
@media (max-width: 600px) {
    .schedule-buttons {
        grid-template-columns: repeat(2, 1fr);
    }
}