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

:root {
    --primary: #6366f1;
    --primary-hover: #4f46e5;
    --bg: #f8fafc;
    --card-bg: #ffffff;
    --text: #1e293b;
    --text-light: #64748b;
    --border: #e2e8f0;
    --today-bg: #e0e7ff;
    --today-border: #6366f1;
    --selected-bg: #c7d2fe;
    --event-bg: #f1f5f9;
    --danger: #ef4444;
    --shadow: 0 4px 6px -1px rgba(0, 0, 0, 0.1), 0 2px 4px -2px rgba(0, 0, 0, 0.1);
}

body {
    font-family: 'Inter', sans-serif;
    background: var(--bg);
    color: var(--text);
    min-height: 100vh;
    padding: 20px;
}

.app-container {
    max-width: 900px;
    margin: 0 auto;
}

.header {
    text-align: center;
    margin-bottom: 30px;
}

.header h1 {
    font-size: 2.5rem;
    font-weight: 700;
    color: var(--text);
    margin-bottom: 5px;
}

.subtitle {
    color: var(--text-light);
    font-size: 1rem;
}

.calendar-container {
    background: var(--card-bg);
    border-radius: 16px;
    padding: 24px;
    box-shadow: var(--shadow);
    margin-bottom: 20px;
}

.calendar-header {
    display: flex;
    justify-content: space-between;
    align-items: center;
    margin-bottom: 24px;
}

.calendar-header h2 {
    font-size: 1.5rem;
    font-weight: 600;
}

.nav-btn {
    background: var(--bg);
    border: 1px solid var(--border);
    padding: 10px 16px;
    border-radius: 8px;
    cursor: pointer;
    font-size: 1rem;
    color: var(--text);
    transition: all 0.2s ease;
}

.nav-btn:hover {
    background: var(--primary);
    color: white;
    border-color: var(--primary);
}

.weekdays {
    display: grid;
    grid-template-columns: repeat(7, 1fr);
    gap: 4px;
    margin-bottom: 8px;
}

.weekday {
    text-align: center;
    font-weight: 600;
    color: var(--text-light);
    font-size: 0.875rem;
    padding: 8px;
}

.calendar-days {
    display: grid;
    grid-template-columns: repeat(7, 1fr);
    gap: 4px;
}

.day {
    aspect-ratio: 1;
    display: flex;
    flex-direction: column;
    align-items: center;
    justify-content: center;
    border-radius: 12px;
    cursor: pointer;
    transition: all 0.2s ease;
    position: relative;
    font-weight: 500;
    background: transparent;
    border: 2px solid transparent;
}

.day:hover:not(.empty) {
    background: var(--event-bg);
}

.day.today {
    background: var(--today-bg);
    border-color: var(--today-border);
    color: var(--primary);
    font-weight: 700;
}

.day.selected {
    background: var(--selected-bg);
    border-color: var(--primary);
}

.day.empty {
    cursor: default;
}

.day.other-month {
    color: var(--border);
}

.day.has-events::after {
    content: '';
    position: absolute;
    bottom: 6px;
    width: 6px;
    height: 6px;
    border-radius: 50%;
    background: var(--primary);
}

.events-panel {
    background: var(--card-bg);
    border-radius: 16px;
    padding: 24px;
    box-shadow: var(--shadow);
}

.events-panel h3 {
    font-size: 1.25rem;
    margin-bottom: 16px;
    color: var(--text);
}

.events-list {
    min-height: 100px;
    max-height: 200px;
    overflow-y: auto;
}

.no-events {
    color: var(--text-light);
    font-style: italic;
    text-align: center;
    padding: 20px;
}

.event-item {
    display: flex;
    justify-content: space-between;
    align-items: center;
    background: var(--event-bg);
    padding: 12px 16px;
    border-radius: 8px;
    margin-bottom: 8px;
    transition: all 0.2s ease;
}

.event-item:hover {
    background: var(--border);
}

.event-text {
    flex: 1;
    font-size: 0.95rem;
}

.delete-event {
    background: none;
    border: none;
    color: var(--danger);
    cursor: pointer;
    padding: 4px 8px;
    font-size: 1.2rem;
    opacity: 0.6;
    transition: opacity 0.2s;
}

.delete-event:hover {
    opacity: 1;
}

.event-form {
    display: flex;
    gap: 10px;
    margin-top: 16px;
}

.event-form.hidden {
    display: none;
}

#eventInput {
    flex: 1;
    padding: 12px 16px;
    border: 2px solid var(--border);
    border-radius: 8px;
    font-size: 1rem;
    font-family: inherit;
    transition: border-color 0.2s;
}

#eventInput:focus {
    outline: none;
    border-color: var(--primary);
}

.add-btn {
    background: var(--primary);
    color: white;
    border: none;
    padding: 12px 24px;
    border-radius: 8px;
    font-size: 1rem;
    font-weight: 600;
    cursor: pointer;
    transition: background 0.2s;
}

.add-btn:hover {
    background: var(--primary-hover);
}

.today-btn {
    position: fixed;
    bottom: 30px;
    right: 30px;
    background: var(--primary);
    color: white;
    border: none;
    padding: 14px 24px;
    border-radius: 30px;
    font-size: 1rem;
    font-weight: 600;
    cursor: pointer;
    box-shadow: 0 4px 15px rgba(99, 102, 241, 0.4);
    transition: all 0.3s ease;
}

.today-btn:hover {
    background: var(--primary-hover);
    transform: translateY(-2px);
}

@media (max-width: 600px) {
    .app-container {
        padding: 0 10px;
    }
    
    .calendar-container, .events-panel {
        padding: 16px;
    }
    
    .header h1 {
        font-size: 2rem;
    }
    
    .day {
        font-size: 0.875rem;
    }
}