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

body {
    font-family: -apple-system, BlinkMacSystemFont, 'Segoe UI', Roboto, Oxygen, Ubuntu, Cantarell, sans-serif;
    background: linear-gradient(135deg, #667eea 0%, #764ba2 100%);
    min-height: 100vh;
    padding: 20px;
}

.container {
    max-width: 1200px;
    margin: 0 auto;
    background: white;
    border-radius: 20px;
    padding: 30px;
    box-shadow: 0 20px 60px rgba(0, 0, 0, 0.3);
}

header {
    text-align: center;
    margin-bottom: 40px;
    padding-bottom: 20px;
    border-bottom: 2px solid #f0f0f0;
}

header h1 {
    color: #333;
    font-size: 2.5em;
    margin-bottom: 10px;
}

.subtitle {
    color: #666;
    font-size: 1.1em;
}

/* Ladder Grid Section */
.ladder-grid-section {
    margin-bottom: 40px;
}

.ladder-grid-section h2 {
    text-align: center;
    color: #333;
    margin-bottom: 30px;
    font-size: 1.8em;
}

.ladder-grid {
    display: flex;
    flex-direction: column;
    gap: 26px;
    align-items: flex-start;
}

.ladder-row {
    display: flex;
    gap: 30px;
    align-items: center;
}

.ladder-group {
    display: flex;
    gap: 10px;
}

.ladder-box {
    width: 50px;
    height: 50px;
    border: 3px solid #333;
    border-radius: 8px;
    background: white;
    transition: all 0.3s;
    cursor: pointer;
    position: relative;
}

.ladder-box:hover {
    transform: scale(1.1);
    box-shadow: 0 4px 12px rgba(0, 0, 0, 0.2);
}

.ladder-box.completed {
    background: linear-gradient(135deg, #C0C0C0 0%, #E8E8E8 100%);
    border-color: #A0A0A0;
}

.ladder-box.bonus.completed {
    background: linear-gradient(135deg, #FFD700 0%, #FFA500 100%);
    border-color: #DAA520;
}

.ladder-box::after {
    content: attr(data-ladder);
    position: absolute;
    bottom: -22px;
    left: 50%;
    transform: translateX(-50%);
    font-size: 0.75em;
    color: #666;
    font-weight: 600;
}

.ladder-box.bonus::after {
    content: 'B';
    color: #DAA520;
    font-weight: bold;
}

/* Filter Section */
.filter-section {
    display: flex;
    gap: 20px;
    align-items: center;
    margin-bottom: 30px;
    flex-wrap: wrap;
}

.filter-section label {
    font-weight: 600;
    color: #333;
}

.filter-section select {
    padding: 8px 16px;
    border: 2px solid #e0e0e0;
    border-radius: 8px;
    font-size: 1em;
    cursor: pointer;
    background: white;
    transition: border-color 0.3s;
}

.filter-section select:hover {
    border-color: #667eea;
}

/* Problems Section */
.problems-section h2 {
    color: #333;
    margin-bottom: 20px;
}

.problems-list {
    display: flex;
    flex-direction: column;
    gap: 12px;
}

.problem-card {
    border: 2px solid #e0e0e0;
    border-radius: 12px;
    padding: 15px 20px;
    background: white;
    transition: all 0.3s;
    display: flex;
    align-items: center;
    gap: 15px;
    justify-content: space-between;
}

.problem-card:hover {
    transform: translateY(-2px);
    box-shadow: 0 5px 20px rgba(0, 0, 0, 0.1);
}

.problem-card.completed {
    border-color: #4caf50;
    background: #f1f8f4;
}

.problem-card.in-progress {
    border-color: #ff9800;
    background: #fff8f1;
}

.problem-info {
    display: flex;
    align-items: center;
    gap: 10px;
    flex: 1;
}

.problem-name {
    font-size: 1.1em;
    font-weight: bold;
    color: #333;
}

.problem-location {
    color: #666;
    font-size: 0.95em;
}

.problem-color-indicator {
    width: 20px;
    height: 20px;
    border-radius: 50%;
    border: 2px solid #333;
    flex-shrink: 0;
}

.problem-status {
    display: flex;
    gap: 8px;
}

.status-btn {
    padding: 6px 12px;
    border: none;
    border-radius: 6px;
    cursor: pointer;
    font-size: 0.8em;
    font-weight: 600;
    transition: all 0.3s;
    white-space: nowrap;
}

.status-btn.not-started {
    background: #e0e0e0;
    color: #666;
}

.status-btn.in-progress {
    background: #ff9800;
    color: white;
}

.status-btn.completed {
    background: #4caf50;
    color: white;
}

.status-btn:hover {
    opacity: 0.8;
    transform: scale(1.05);
}

.status-btn.active {
    box-shadow: 0 2px 10px rgba(0, 0, 0, 0.2);
}

/* Responsive Design */
@media (max-width: 768px) {
    .container {
        padding: 20px;
    }

    header h1 {
        font-size: 2em;
    }

    .ladder-box {
        width: 45px;
        height: 45px;
    }

    .ladder-row {
        display: flex;
        align-items: flex-start;
        flex-direction: column; /* stack groups in this row */
        gap: 26px;
        width: 100%;
    }

    .ladder-group {
        display: flex;
        gap: 12px;
        flex-wrap: wrap; /* allow boxes within a group to wrap to next line */
        width: auto;
        align-items: center;
    }

    .problem-card {
        flex-direction: column;
        align-items: flex-start;
    }

    .problem-status {
        width: 100%;
        flex-direction: column;
    }

    .status-btn {
        width: 100%;
    }
}

@media (max-width: 480px) {
    .ladder-box {
        width: 36px;
        height: 36px;
    }

    .ladder-group {
        gap: 8px;
    }
}