/* Reset & Base */
*,
*::before,
*::after {
    margin: 0;
    padding: 0;
    box-sizing: border-box;
}

html {
    font-size: 16px;
    scroll-behavior: smooth;
}

body {
    font-family: 'Inter', -apple-system, BlinkMacSystemFont, 'Segoe UI', Roboto, sans-serif;
    background-color: #ffffff;
    color: #2c3e50;
    line-height: 1.7;
    -webkit-font-smoothing: antialiased;
}

/* Layout */
main {
    max-width: 720px;
    margin: 0 auto;
    padding: 3rem 1.5rem 2rem;
}

/* Hero */
.hero {
    text-align: center;
    margin-bottom: 3rem;
    padding-bottom: 2.5rem;
    border-bottom: 1px solid #e0e0e0;
}

.hero h1 {
    font-size: 2rem;
    font-weight: 700;
    line-height: 1.3;
    margin-bottom: 1.25rem;
    color: #1a1a1a;
}

.hero .highlight {
    color: #27ae60;
    text-decoration: underline;
    text-decoration-color: #27ae6066;
    text-underline-offset: 4px;
}

#rotating-text {
    display: inline-block;
    transition: opacity 0.3s ease-in-out;
}

.hero .subtitle {
    font-size: 1.1rem;
    color: #555;
    margin-bottom: 1rem;
}

.hero p {
    font-size: 1.05rem;
    color: #444;
}

.hero em {
    color: #e74c3c;
    font-style: italic;
}

/* Sections */
section {
    margin-bottom: 2.5rem;
}

h2 {
    font-size: 1.4rem;
    font-weight: 600;
    margin-bottom: 1rem;
    color: #1a1a1a;
}

/* Chat */
.chat {
    background-color: #f8f9fa;
    border: 1px solid #e0e0e0;
    border-radius: 12px;
    padding: 1.25rem;
    margin-bottom: 1rem;
}

.message {
    display: flex;
    gap: 0.75rem;
    margin-bottom: 1rem;
}

.message:last-child {
    margin-bottom: 0;
}

.avatar {
    width: 38px;
    height: 38px;
    border-radius: 8px;
    display: flex;
    align-items: center;
    justify-content: center;
    font-weight: 700;
    font-size: 0.9rem;
    color: #fff;
    flex-shrink: 0;
}

.content {
    flex: 1;
    min-width: 0;
}

.meta {
    display: flex;
    align-items: baseline;
    gap: 0.5rem;
    margin-bottom: 0.25rem;
}

.name {
    font-weight: 600;
    font-size: 0.95rem;
    color: #1a1a1a;
}

.time {
    font-size: 0.75rem;
    color: #999;
}

.bubble {
    font-size: 0.95rem;
    color: #333;
    line-height: 1.5;
}

.reaction {
    margin-top: 0.5rem;
    padding: 0.25rem 0.75rem;
    background-color: #e8e8e8;
    border: 1px solid #d0d0d0;
    border-radius: 20px;
    display: inline-block;
    font-size: 0.8rem;
    color: #666;
    margin-left: 3.25rem;
}

/* Explanation text */
.explanation {
    font-size: 0.95rem;
    color: #555;
    padding: 0 0.25rem;
    line-height: 1.6;
}

/* Example sections */
.example.bad h2 {
    color: #e74c3c;
}

.example.good h2 {
    color: #27ae60;
}

/* Why section */
.reasons {
    display: grid;
    grid-template-columns: repeat(auto-fit, minmax(200px, 1fr));
    gap: 1.25rem;
    margin-top: 1rem;
}

.reason {
    background-color: #f8f9fa;
    border: 1px solid #e0e0e0;
    border-radius: 12px;
    padding: 1.25rem;
    text-align: center;
}

.reason-icon {
    font-size: 2rem;
    margin-bottom: 0.5rem;
}

.reason h3 {
    font-size: 1rem;
    font-weight: 600;
    color: #1a1a1a;
    margin-bottom: 0.5rem;
}

.reason p {
    font-size: 0.9rem;
    color: #555;
    line-height: 1.5;
}

/* Tip section */
.tip p {
    color: #444;
    margin-bottom: 1rem;
}

.examples-list {
    display: flex;
    flex-direction: column;
    gap: 0.5rem;
}

.example-item {
    display: flex;
    align-items: center;
    gap: 0.75rem;
    padding: 0.75rem 1rem;
    border-radius: 8px;
    font-size: 0.95rem;
}

.good-item {
    background-color: #d4edda;
    border: 1px solid #c3e6cb;
    color: #155724;
}

.bad-item {
    background-color: #f8d7da;
    border: 1px solid #f5c6cb;
    color: #721c24;
}

.tag {
    flex-shrink: 0;
    font-size: 0.85rem;
}

/* Note */
.note {
    background-color: #f8f9fa;
    border: 1px solid #007bff44;
    border-left: 4px solid #007bff;
    border-radius: 8px;
    padding: 1rem 1.25rem;
    margin-bottom: 2.5rem;
}

.note p {
    font-size: 0.95rem;
    color: #333;
    line-height: 1.6;
}

/* Footer */
footer {
    text-align: center;
    padding-top: 2rem;
    border-top: 1px solid #e0e0e0;
}

footer p {
    font-size: 0.9rem;
    color: #666;
    margin-bottom: 0.5rem;
}

footer a {
    color: #007bff;
    text-decoration: none;
}

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

.footer-small {
    font-size: 0.8rem !important;
    color: #999 !important;
}

.footer-love {
    margin-top: 1.5rem;
    font-size: 0.85rem;
    color: #888;
    padding-top: 1rem;
    border-top: 1px solid #f0f0f0;
}

.footer-love a {
    color: #27ae60;
    font-weight: 600;
    text-decoration: none;
}

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

/* Responsive */
@media (max-width: 600px) {
    main {
        padding: 2rem 1rem 1.5rem;
    }

    .hero h1 {
        font-size: 1.5rem;
    }

    .reasons {
        grid-template-columns: 1fr;
    }
}