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

body {
    font-family: 'Noto Serif SC', serif;
    background: linear-gradient(135deg, #f5f7fa 0%, #e4e8eb 100%);
    min-height: 100vh;
    padding: 20px;
    color: #4a4a4a;
}

.container {
    max-width: 1200px;
    margin: 0 auto;
}

header {
    text-align: center;
    margin-bottom: 40px;
    padding: 30px 0;
}

header h1 {
    font-size: 2.5rem;
    font-weight: 600;
    color: #6b8e9e;
    margin-bottom: 10px;
}

.subtitle {
    font-size: 1rem;
    color: #8a9ea8;
    font-style: italic;
}

.main-content {
    display: grid;
    grid-template-columns: 1fr 1fr;
    gap: 30px;
}

.calendar-section, .todo-section {
    background: rgba(255, 255, 255, 0.9);
    border-radius: 20px;
    padding: 25px;
    box-shadow: 0 8px 32px rgba(0, 0, 0, 0.08);
}

.calendar-header {
    display: flex;
    justify-content: space-between;
    align-items: center;
    margin-bottom: 20px;
}

.calendar-header h2 {
    font-size: 1.5rem;
    color: #6b8e9e;
}

.nav-btn {
    background: #d4e2e8;
    border: none;
    width: 40px;
    height: 40px;
    border-radius: 50%;
    font-size: 1.2rem;
    color: #6b8e9e;
    cursor: pointer;
    transition: all 0.3s ease;
}

.nav-btn:hover {
    background: #b8ccd6;
    transform: scale(1.05);
}

.calendar-weekdays {
    display: grid;
    grid-template-columns: repeat(7, 1fr);
    gap: 5px;
    margin-bottom: 10px;
}

.calendar-weekdays span {
    text-align: center;
    font-weight: 600;
    color: #8a9ea8;
    padding: 10px 0;
}

.calendar-grid {
    display: grid;
    grid-template-columns: repeat(7, 1fr);
    gap: 5px;
}

.calendar-day {
    aspect-ratio: 1;
    display: flex;
    flex-direction: column;
    justify-content: center;
    align-items: center;
    border-radius: 12px;
    cursor: pointer;
    transition: all 0.3s ease;
    position: relative;
}

.calendar-day:hover {
    background: #e8f0f4;
}

.calendar-day.empty {
    cursor: default;
    background: transparent;
}

.calendar-day.empty:hover {
    background: transparent;
}

.calendar-day.today {
    background: linear-gradient(135deg, #a8c5d4 0%, #8fb3c6 100%);
    color: white;
}

.calendar-day.selected {
    background: linear-gradient(135deg, #d4a5a5 0%, #c68f8f 100%);
    color: white;
}

.calendar-day .day-number {
    font-size: 1rem;
    font-weight: 500;
}

.calendar-day .has-todo {
    position: absolute;
    bottom: 5px;
    width: 6px;
    height: 6px;
    background: #d4a5a5;
    border-radius: 50%;
}

.todo-header {
    display: flex;
    justify-content: space-between;
    align-items: center;
    margin-bottom: 20px;
}

.todo-header h3 {
    font-size: 1.3rem;
    color: #6b8e9e;
}

.add-btn {
    background: linear-gradient(135deg, #a8d4c5 0%, #8fc6b3 100%);
    border: none;
    padding: 10px 20px;
    border-radius: 25px;
    color: white;
    font-size: 0.95rem;
    cursor: pointer;
    transition: all 0.3s ease;
    font-family: inherit;
}

.add-btn:hover {
    transform: translateY(-2px);
    box-shadow: 0 4px 12px rgba(137, 198, 179, 0.4);
}

.todo-list {
    max-height: 400px;
    overflow-y: auto;
}

.todo-item {
    background: #f8fafb;
    border-radius: 12px;
    padding: 15px;
    margin-bottom: 12px;
    display: flex;
    align-items: flex-start;
    gap: 12px;
    transition: all 0.3s ease;
}

.todo-item:hover {
    transform: translateX(5px);
    box-shadow: 0 4px 12px rgba(0, 0, 0, 0.06);
}

.todo-item.completed {
    opacity: 0.6;
}

.todo-item.completed .todo-title {
    text-decoration: line-through;
}

.todo-checkbox {
    width: 22px;
    height: 22px;
    border: 2px solid #d4a5a5;
    border-radius: 50%;
    cursor: pointer;
    display: flex;
    align-items: center;
    justify-content: center;
    transition: all 0.3s ease;
    flex-shrink: 0;
    margin-top: 3px;
}

.todo-checkbox.checked {
    background: #d4a5a5;
    color: white;
}

.todo-content {
    flex: 1;
}

.todo-title {
    font-weight: 600;
    color: #5a6a72;
    margin-bottom: 5px;
}

.todo-desc {
    font-size: 0.9rem;
    color: #8a9ea8;
    margin-bottom: 5px;
}

.todo-time {
    font-size: 0.85rem;
    color: #a8b8c0;
}

.todo-delete {
    background: transparent;
    border: none;
    color: #d4a5a5;
    cursor: pointer;
    font-size: 1.2rem;
    opacity: 0;
    transition: all 0.3s ease;
}

.todo-item:hover .todo-delete {
    opacity: 1;
}

.modal {
    display: none;
    position: fixed;
    top: 0;
    left: 0;
    width: 100%;
    height: 100%;
    background: rgba(0, 0, 0, 0.4);
    z-index: 1000;
    justify-content: center;
    align-items: center;
}

.modal.active {
    display: flex;
}

.modal-content {
    background: white;
    border-radius: 20px;
    padding: 30px;
    width: 90%;
    max-width: 450px;
    box-shadow: 0 10px 40px rgba(0, 0, 0, 0.2);
    animation: slideUp 0.3s ease;
}

@keyframes slideUp {
    from {
        opacity: 0;
        transform: translateY(20px);
    }
    to {
        opacity: 1;
        transform: translateY(0);
    }
}

.modal-content h3 {
    font-size: 1.5rem;
    color: #6b8e9e;
    margin-bottom: 20px;
}

.modal-content input,
.modal-content textarea {
    width: 100%;
    padding: 12px 15px;
    margin-bottom: 15px;
    border: 2px solid #e4e8eb;
    border-radius: 10px;
    font-size: 1rem;
    font-family: inherit;
    transition: all 0.3s ease;
}

.modal-content input:focus,
.modal-content textarea:focus {
    outline: none;
    border-color: #a8c5d4;
}

.modal-actions {
    display: flex;
    gap: 10px;
    justify-content: flex-end;
}

.btn-cancel, .btn-save {
    padding: 10px 25px;
    border-radius: 25px;
    font-size: 1rem;
    cursor: pointer;
    border: none;
    font-family: inherit;
    transition: all 0.3s ease;
}

.btn-cancel {
    background: #e4e8eb;
    color: #6b8e9e;
}

.btn-cancel:hover {
    background: #d4dde4;
}

.btn-save {
    background: linear-gradient(135deg, #a8c5d4 0%, #8fb3c6 100%);
    color: white;
}

.btn-save:hover {
    transform: translateY(-2px);
    box-shadow: 0 4px 12px rgba(143, 179, 198, 0.4);
}

.empty-state {
    text-align: center;
    padding: 40px 20px;
    color: #a8b8c0;
}

.empty-state p {
    font-size: 1rem;
}

@media (max-width: 768px) {
    .main-content {
        grid-template-columns: 1fr;
    }
    
    header h1 {
        font-size: 2rem;
    }
}