:root {
    --tg-theme-bg-color: #ffffff;
    --tg-theme-text-color: #000000;
    --tg-theme-hint-color: #999999;
    --tg-theme-link-color: #2481cc;
    --tg-theme-button-color: #2481cc;
    --tg-theme-button-text-color: #ffffff;
    --tg-theme-secondary-bg-color: #f0f0f0;
}

body {
    background-color: var(--tg-theme-bg-color);
    color: var(--tg-theme-text-color);
    font-family: -apple-system, BlinkMacSystemFont, "Segoe UI", Roboto, Helvetica, Arial, sans-serif;
    margin: 0;
    padding: 0;
}

#app {
    padding: 16px;
}

header {
    margin-bottom: 20px;
    text-align: center;
}

nav {
    display: flex;
    justify-content: space-around;
    margin-bottom: 20px;
    border-bottom: 1px solid var(--tg-theme-hint-color);
}

.tab-btn {
    background: none;
    border: none;
    color: var(--tg-theme-hint-color);
    padding: 10px;
    font-size: 16px;
    cursor: pointer;
}

.tab-btn.active {
    color: var(--tg-theme-link-color);
    border-bottom: 2px solid var(--tg-theme-link-color);
}

.tab-content {
    display: none;
}

.tab-content.active {
    display: block;
}

.form-group, .form-row {
    margin-bottom: 15px;
}

.form-row {
    display: flex;
    gap: 10px;
}

.form-group.row {
    display: flex;
    align-items: center;
    justify-content: space-between;
}

input, select {
    width: 100%;
    padding: 10px;
    box-sizing: border-box;
    border: 1px solid var(--tg-theme-hint-color);
    border-radius: 8px;
    background-color: var(--tg-theme-secondary-bg-color);
    color: var(--tg-theme-text-color);
}

button.primary-btn {
    width: 100%;
    padding: 12px;
    background-color: var(--tg-theme-button-color);
    color: var(--tg-theme-button-text-color);
    border: none;
    border-radius: 8px;
    font-size: 16px;
    cursor: pointer;
    margin-top: 10px;
}

button.secondary-btn {
    width: 100%;
    padding: 8px;
    background-color: transparent;
    color: var(--tg-theme-button-color);
    border: 1px solid var(--tg-theme-button-color);
    border-radius: 8px;
    margin-top: 5px;
    cursor: pointer;
}

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

.birthdays-list li {
    padding: 10px;
    background-color: var(--tg-theme-secondary-bg-color);
    margin-bottom: 5px;
    border-radius: 8px;
    display: flex;
    justify-content: space-between;
    align-items: center;
}

.delete-btn {
    background: none;
    border: none;
    color: red;
    font-size: 20px;
    cursor: pointer;
}