:root {
    --bg: #0f172a;
    --surface: #1e293b;
    --primary: #6366f1;
    --primary-hover: #4f46e5;
    --text: #f1f5f9;
    --text-muted: #94a3b8;
    --border: #334155;
    --success: #22c55e;
    --error: #ef4444;
}

* {
    box-sizing: border-box;
}

body {
    margin: 0;
    font-family: "Segoe UI", Roboto, Helvetica, Arial, sans-serif;
    background: var(--bg);
    color: var(--text);
    line-height: 1.6;
}

.hero {
    background: linear-gradient(135deg, #4f46e5 0%, #7c3aed 60%, #0f172a 100%);
    padding-bottom: 4rem;
}

.navbar {
    display: flex;
    justify-content: space-between;
    align-items: center;
    padding: 1.5rem 2rem;
}

.brand {
    font-size: 1.4rem;
    font-weight: 600;
}

.nav-links a {
    color: var(--text);
    margin-left: 1.5rem;
    text-decoration: none;
    font-weight: 500;
}

.nav-links a:hover {
    text-decoration: underline;
}

.hero-content {
    text-align: center;
    padding: 4rem 1.5rem 1rem;
}

.hero-content h1 {
    font-size: 3.5rem;
    margin: 0 0 0.5rem;
}

.subtitle {
    font-size: 1.25rem;
    color: #e2e8f0;
}

.details {
    color: #cbd5e1;
    margin-bottom: 2rem;
}

.cta-button {
    display: inline-block;
    background: var(--primary);
    color: white;
    padding: 0.9rem 2rem;
    border-radius: 8px;
    font-weight: 600;
    text-decoration: none;
    transition: background 0.2s ease;
}

.cta-button:hover {
    background: var(--primary-hover);
}

.cta-button.secondary {
    background: transparent;
    border: 1px solid var(--border);
}

main {
    max-width: 1000px;
    margin: 0 auto;
    padding: 0 1.5rem;
}

.section {
    padding: 3rem 0;
    border-bottom: 1px solid var(--border);
}

.section h2 {
    font-size: 2rem;
    margin-bottom: 1.5rem;
}

.agenda-list {
    display: flex;
    flex-direction: column;
    gap: 1rem;
}

.agenda-item {
    display: flex;
    gap: 1.5rem;
    background: var(--surface);
    padding: 1rem 1.5rem;
    border-radius: 10px;
    align-items: center;
}

.agenda-time {
    font-weight: 700;
    color: var(--primary);
    min-width: 60px;
}

.agenda-title {
    margin: 0;
    font-weight: 600;
}

.agenda-track {
    font-size: 0.85rem;
    color: var(--text-muted);
}

.speakers-grid {
    display: grid;
    grid-template-columns: repeat(auto-fit, minmax(220px, 1fr));
    gap: 1.5rem;
}

.speaker-card {
    background: var(--surface);
    padding: 1.5rem;
    border-radius: 10px;
    text-align: center;
}

.speaker-card img {
    width: 88px;
    height: 88px;
    border-radius: 50%;
    margin-bottom: 1rem;
    object-fit: cover;
}

.speaker-card h3 {
    margin: 0.25rem 0;
}

.speaker-role {
    color: var(--text-muted);
    font-size: 0.9rem;
    margin: 0.25rem 0;
}

.speaker-topic {
    font-size: 0.9rem;
    color: #c7d2fe;
}

.login-section {
    text-align: center;
}

.login-hint {
    color: var(--text-muted);
    font-size: 0.9rem;
}

.login-form {
    max-width: 320px;
    margin: 1.5rem auto 0;
    display: flex;
    flex-direction: column;
    gap: 0.5rem;
    text-align: left;
}

.login-form label {
    font-size: 0.85rem;
    color: var(--text-muted);
}

.login-form input {
    padding: 0.65rem 0.75rem;
    border-radius: 6px;
    border: 1px solid var(--border);
    background: var(--surface);
    color: var(--text);
}

.login-form button {
    margin-top: 0.75rem;
    padding: 0.75rem;
    border: none;
    border-radius: 6px;
    background: var(--primary);
    color: white;
    font-weight: 600;
    cursor: pointer;
}

.login-form button:hover {
    background: var(--primary-hover);
}

.api-section ul {
    list-style: none;
    padding: 0;
}

.api-section li {
    margin-bottom: 0.5rem;
}

.api-section a {
    color: #93c5fd;
    text-decoration: none;
}

.api-section code {
    background: var(--surface);
    padding: 0.2rem 0.5rem;
    border-radius: 4px;
}

.flash-container {
    margin-top: 1.5rem;
    display: flex;
    flex-direction: column;
    gap: 0.5rem;
}

.flash {
    padding: 0.75rem 1rem;
    border-radius: 6px;
    font-weight: 500;
}

.flash-success {
    background: rgba(34, 197, 94, 0.15);
    color: var(--success);
    border: 1px solid var(--success);
}

.flash-error {
    background: rgba(239, 68, 68, 0.15);
    color: var(--error);
    border: 1px solid var(--error);
}

footer {
    text-align: center;
    padding: 2rem;
    color: var(--text-muted);
    font-size: 0.85rem;
}