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

body {
    font-family: -apple-system, BlinkMacSystemFont, 'Segoe UI', Roboto, Oxygen, Ubuntu, Cantarell, sans-serif;
    line-height: 1.5;
    color: #d0d0d0;
    background-color: #050810;
}

.navbar {
    background-color: #0d1117;
    padding: 0.6rem 0;
    position: sticky;
    top: 0;
    z-index: 1000;
    box-shadow: 0 1px 3px rgba(0,0,0,0.5);
    border-bottom: 1px solid #161b22;
    position: relative;
}

.progress-bar-container {
    position: absolute;
    bottom: 0;
    left: 0;
    right: 0;
    height: 2px;
    background-color: #161b22;
    overflow: hidden;
}

.progress-bar-fill {
    height: 100%;
    background: linear-gradient(90deg, #00d4ff, #ffa500);
    width: 0%;
    transition: width 0.3s ease;
    animation: shimmer 2s infinite;
}

@keyframes shimmer {
    0%, 100% {
        opacity: 1;
    }
    50% {
        opacity: 0.7;
    }
}

.nav-container {
    max-width: 1400px;
    margin: 0 auto;
    padding: 0 2rem;
    display: flex;
    justify-content: space-between;
    align-items: center;
    position: relative;
    z-index: 10;
}

.logo {
    font-size: 1.3rem;
    font-weight: 700;
    color: #00d4ff;
    letter-spacing: 3px;
}

.nav-menu {
    display: flex;
    list-style: none;
    gap: 0;
    align-items: center;
}

.nav-menu > li {
    position: relative;
}

.nav-menu a {
    color: #b0b0b0;
    text-decoration: none;
    padding: 0.6rem 1rem;
    display: block;
    transition: all 0.2s;
    font-size: 0.9rem;
    font-weight: 500;
}

.nav-menu > li > a:hover {
    color: #00d4ff;
    background-color: rgba(0, 212, 255, 0.08);
}

.dropdown {
    position: relative;
}

.dropdown-content {
    display: none;
    position: absolute;
    top: calc(100% + 0.25rem);
    left: 0;
    background-color: #0d1117;
    min-width: 200px;
    box-shadow: 0 4px 12px rgba(0,0,0,0.4);
    border: 1px solid #30363d;
    border-radius: 4px;
    z-index: 100;
    padding: 0.5rem 0;
}

.dropdown:hover .dropdown-content,
.dropdown-content:hover {
    display: block;
}

.dropdown > a:hover + .dropdown-content {
    display: block;
}

.dropdown-content a {
    padding: 0.75rem 1.25rem;
    border-bottom: 1px solid #30363d;
    display: block;
    color: #b0b0b0;
}

.dropdown-content a:last-child {
    border-bottom: none;
}

.dropdown-content a:hover {
    background-color: rgba(0, 212, 255, 0.12);
    color: #00d4ff;
}

.dropdown > a::after {
    content: ' ▾';
    font-size: 0.8rem;
}

.week-info {
    background: linear-gradient(135deg, #0d1117 0%, #161b22 100%);
    border: 1px solid #30363d;
    border-radius: 6px;
    padding: 1.25rem 1.5rem;
    margin: 1.5rem auto;
    max-width: 1400px;
    display: grid;
    grid-template-columns: auto 1fr auto;
    gap: 1.5rem;
    align-items: center;
}

.week-number {
    font-size: 1.1rem;
    font-weight: 700;
    color: #00d4ff;
    text-transform: uppercase;
    letter-spacing: 1px;
}

.week-theme {
    color: #b0b0b0;
    font-size: 0.95rem;
}

.week-theme strong {
    color: #ffa500;
}

.practice-link {
    background-color: #00d4ff;
    color: #050810;
    padding: 0.5rem 1.25rem;
    border-radius: 4px;
    text-decoration: none;
    font-weight: 600;
    transition: all 0.2s;
    font-size: 0.9rem;
}

.practice-link:hover {
    background-color: #00e6ff;
    transform: translateY(-1px);
    box-shadow: 0 2px 8px rgba(0, 212, 255, 0.2);
}

.contest-container {
    background: linear-gradient(135deg, #0d1117 0%, #161b22 100%);
    border: 2px solid #ff4444;
    border-radius: 8px;
    padding: 2rem;
    margin: 1.5rem auto;
    max-width: 1400px;
    text-align: center;
}

.contest-title {
    font-size: 2rem;
    color: #ff4444;
    margin-bottom: 1rem;
    font-weight: 700;
    letter-spacing: 1px;
}

.countdown {
    font-size: 2.5rem;
    color: #00d4ff;
    font-weight: 700;
    margin: 1.5rem 0;
    font-family: 'Courier New', monospace;
    letter-spacing: 2px;
}

.countdown-label {
    font-size: 0.85rem;
    color: #808080;
    margin-bottom: 0.5rem;
    text-transform: uppercase;
    letter-spacing: 1px;
}

.problems-preview {
    display: grid;
    grid-template-columns: repeat(auto-fit, minmax(200px, 1fr));
    gap: 1rem;
    margin-top: 1.5rem;
}

.problem-card {
    background-color: #161b22;
    border: 1px solid #30363d;
    border-radius: 6px;
    padding: 1rem;
    transition: all 0.2s;
}

.problem-card:hover {
    border-color: #ff4444;
    transform: translateY(-2px);
    box-shadow: 0 2px 6px rgba(255, 68, 68, 0.15);
}

.problem-name {
    font-size: 1rem;
    color: #ffa500;
    font-weight: 600;
    margin-bottom: 0.5rem;
}

.problem-difficulty {
    font-size: 0.8rem;
    color: #808080;
}

.container {
    max-width: 1400px;
    margin: 0 auto;
    padding: 2rem;
}

.features {
    display: grid;
    grid-template-columns: repeat(auto-fit, minmax(300px, 1fr));
    gap: 2rem;
    margin-bottom: 4rem;
}

.feature-card {
    background: #16213e;
    padding: 2rem;
    border-radius: 8px;
    border: 2px solid #2a2a3e;
    transition: all 0.3s;
}

.feature-card:hover {
    transform: translateY(-5px);
    border-color: #ff6b6b;
}

.feature-card h3 {
    font-size: 1.5rem;
    margin-bottom: 1rem;
    color: #ff6b6b;
}

.latest h2 {
    font-size: 2rem;
    margin-bottom: 2rem;
    color: #ff6b6b;
}

.problem-list {
    display: grid;
    gap: 1.5rem;
}

.problem-item {
    background: #16213e;
    padding: 1.5rem;
    border-radius: 8px;
    border: 2px solid #2a2a3e;
    display: flex;
    flex-direction: column;
    gap: 0.5rem;
    transition: all 0.3s;
}

.problem-item:hover {
    border-color: #ff6b6b;
}

.problem-item h3 {
    color: #ffb800;
}

.difficulty {
    display: inline-block;
    padding: 0.25rem 0.75rem;
    border-radius: 12px;
    font-size: 0.875rem;
    font-weight: bold;
    width: fit-content;
}

.difficulty.easy {
    background-color: rgba(0, 168, 198, 0.2);
    color: #00a8c6;
    border: 1px solid #00a8c6;
}

.difficulty.medium {
    background-color: rgba(255, 184, 0, 0.2);
    color: #ffb800;
    border: 1px solid #ffb800;
}

.difficulty.hard {
    background-color: rgba(255, 107, 107, 0.2);
    color: #ff6b6b;
    border: 1px solid #ff6b6b;
}

.learn-more {
    color: #00d9ff;
    text-decoration: none;
    font-weight: bold;
    margin-top: 0.5rem;
    transition: color 0.2s;
}

.learn-more:hover {
    color: #0088a3;
}

footer {
    background-color: #0d1117;
    color: #606060;
    text-align: center;
    padding: 1.5rem;
    margin-top: 3rem;
    border-top: 1px solid #161b22;
    font-size: 0.9rem;
}

@media (max-width: 768px) {
    .nav-menu {
        gap: 1rem;
    }
}

/* Week Progress Section */
.week-progress {
    display: grid;
    grid-template-columns: repeat(auto-fit, minmax(320px, 1fr));
    gap: 1.5rem;
    margin-top: 2rem;
}

.week-card {
    background: linear-gradient(135deg, #0d1117 0%, #161b22 100%);
    border: 1px solid #30363d;
    border-radius: 8px;
    padding: 1.25rem;
    transition: all 0.2s;
    display: flex;
    flex-direction: column;
}

.week-card:hover {
    transform: translateY(-2px);
    border-color: #444c56;
}

.week-card.active {
    border-color: #00d4ff;
    box-shadow: 0 2px 8px rgba(0, 212, 255, 0.15);
}

.week-card.locked {
    opacity: 0.6;
}

.week-header {
    display: flex;
    justify-content: space-between;
    align-items: center;
    margin-bottom: 1rem;
}

.week-header h2 {
    color: #d0d0d0;
    font-size: 1.3rem;
    font-weight: 700;
}

.week-badge {
    background-color: #30363d;
    color: #808080;
    padding: 0.25rem 0.6rem;
    border-radius: 3px;
    font-size: 0.7rem;
    font-weight: 600;
    text-transform: uppercase;
    letter-spacing: 0.5px;
}

.week-card.active .week-badge {
    background-color: rgba(0, 212, 255, 0.15);
    color: #00d4ff;
}

.week-content {
    flex-grow: 1;
}

.week-theme {
    color: #ffa500;
    font-size: 1rem;
    margin-bottom: 0.75rem;
    font-weight: 500;
}

.week-status {
    display: flex;
    gap: 1rem;
    align-items: center;
    font-size: 0.9rem;
}

.status-indicator {
    color: #808080;
    font-size: 0.9rem;
}

.status-indicator.live {
    color: #00d4ff;
    font-weight: 600;
}

.contest-status {
    color: #00d4ff;
    font-weight: 600;
    font-size: 0.9rem;
}

.unlock-date {
    color: #808080;
    font-size: 0.9rem;
}

.week-link {
    display: inline-block;
    margin-top: 1rem;
    padding: 0.6rem 1.2rem;
    background-color: #00d4ff;
    color: #050810;
    text-decoration: none;
    border-radius: 4px;
    font-weight: 600;
    text-align: center;
    transition: all 0.2s;
    font-size: 0.9rem;
}

.week-link:hover {
    background-color: #00e6ff;
    transform: translateY(-1px);
    box-shadow: 0 2px 6px rgba(0, 212, 255, 0.2);
}

.week-link.disabled {
    background-color: #30363d;
    color: #606060;
    cursor: not-allowed;
}