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

body {
    font-family: 'Segoe UI', Roboto, 'Helvetica Neue', Arial, sans-serif;
    background-color: #0f0f0f;
    color: #f1f1f1;
    min-height: 100vh;
}

.loading,
.error {
    display: flex;
    flex-direction: column;
    align-items: center;
    justify-content: center;
    min-height: 60vh;
    text-align: center;
    padding: 24px;
}

.loading .spinner {
    width: 40px;
    height: 40px;
    border: 3px solid #333;
    border-top-color: #3ea6ff;
    border-radius: 50%;
    animation: spin 0.8s linear infinite;
    margin-bottom: 16px;
}

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

.error h2 {
    font-size: 20px;
    margin-bottom: 8px;
    color: #f1f1f1;
}

.error p {
    color: #aaa;
    font-size: 14px;
}

.error a {
    color: #3ea6ff;
    text-decoration: none;
}

.error a:hover {
    text-decoration: underline;
}

.container {
    max-width: 1600px;
    margin: 0 auto;
    padding: 24px 24px;
}

.header {
    margin-bottom: 20px;
}

.header h1 {
    font-size: 18px;
    font-weight: 600;
    color: #f1f1f1;
    margin-bottom: 4px;
    line-height: 1.4;
}

.header .meta {
    font-size: 13px;
    color: #aaa;
}

.main {
    display: flex;
    flex-direction: column;
    gap: 20px;
}

.video-wrapper {
    position: relative;
    width: 100%;
    padding-bottom: 56.25%;
    background: #000;
    border-radius: 12px;
    overflow: hidden;
}

.video-wrapper iframe {
    position: absolute;
    top: 0;
    left: 0;
    width: 100%;
    height: 100%;
    border: none;
}

.notes-panel {
    background: #1a1a1a;
    border-radius: 12px;
    border: 1px solid #333;
    overflow: hidden;
    display: flex;
    flex-direction: column;
}

.notes-header {
    padding: 16px;
    border-bottom: 1px solid #333;
    display: flex;
    align-items: center;
    justify-content: space-between;
}

.notes-header h2 {
    font-size: 16px;
    font-weight: 600;
}

.notes-header .count {
    font-size: 13px;
    color: #aaa;
}

.notes-list {
    list-style: none;
    overflow-y: auto;
    max-height: 500px;
    padding: 8px 0;
}

.note-item {
    display: flex;
    gap: 12px;
    padding: 12px 16px;
    cursor: pointer;
    transition: background-color 0.15s;
    align-items: flex-start;
}

.note-item:hover {
    background: #252525;
}

.note-item.active {
    background: #1e2a3a;
}

.note-item.highlight {
    animation: highlight-fade 1.2s ease-out;
}

@keyframes highlight-fade {
    0% { background: #2a4a6a; }
    100% { background: transparent; }
}

.note-timestamp {
    flex-shrink: 0;
    background: #3ea6ff22;
    color: #3ea6ff;
    font-size: 12px;
    font-weight: 600;
    padding: 4px 8px;
    border-radius: 6px;
    font-family: 'SF Mono', 'Fira Code', monospace;
    min-width: 52px;
    text-align: center;
    border: none;
    cursor: pointer;
    line-height: 1.4;
}

.note-timestamp:hover {
    background: #3ea6ff44;
}

.note-text {
    font-size: 14px;
    line-height: 1.5;
    color: #ddd;
    white-space: pre-line;
    word-break: break-word;
}

.notes-empty {
    padding: 40px 16px;
    text-align: center;
    color: #777;
    font-size: 14px;
    line-height: 1.6;
}

.notes-empty .empty-icon {
    font-size: 32px;
    margin-bottom: 12px;
    opacity: 0.5;
}

.notes-empty p {
    margin-bottom: 4px;
}

.footer {
    text-align: center;
    padding: 32px 16px;
    font-size: 13px;
    color: #666;
}

.footer .footer-tagline {
    margin-bottom: 12px;
}

.footer a {
    color: #3ea6ff;
    text-decoration: none;
    font-weight: 500;
}

.footer a:hover {
    text-decoration: underline;
}

.footer .cta-button {
    display: inline-block;
    background: #3ea6ff;
    color: #0f0f0f;
    padding: 8px 20px;
    border-radius: 20px;
    font-size: 13px;
    font-weight: 600;
    text-decoration: none;
    transition: background 0.2s, transform 0.15s;
}

.footer .cta-button:hover {
    background: #69bbff;
    text-decoration: none;
    transform: scale(1.03);
}

@media (min-width: 900px) {
    .container {
        padding: 24px 40px;
    }

    .main {
        flex-direction: row;
        align-items: flex-start;
    }

    .video-wrapper {
        flex: 3;
        min-width: 0;
    }

    .notes-panel {
        flex: 1;
        min-width: 300px;
        max-width: 380px;
        flex-shrink: 0;
    }

    .notes-list {
        max-height: calc(100vh - 200px);
    }
}

@media (min-width: 1400px) {
    .container {
        padding: 32px 60px;
    }

    .notes-panel {
        max-width: 420px;
    }

    .header h1 {
        font-size: 22px;
    }
}