body {
    font-family: -apple-system, BlinkMacSystemFont, "Segoe UI", Roboto, sans-serif;
    background-color: #e9ecef;
    margin: 0;
    display: flex;
    justify-content: center;
    align-items: center;
    min-height: 100vh;
}

.app-container {
    background: white;
    width: 100%;
    max-width: 400px;
    height: 80vh;
    min-height: 650px;
    border-radius: 20px;
    box-shadow: 0 10px 30px rgba(0,0,0,0.1);
    display: flex;
    flex-direction: column;
    overflow: hidden;
    position: relative;
}

.app-header {
    display: flex;
    justify-content: space-between;
    align-items: center;
    padding: 20px;
    border-bottom: 1px solid #eee;
}
.app-header h1 { margin: 0; font-size: 20px; color: #1a73e8; cursor: pointer; }
.text-btn { background: none; border: none; font-weight: bold; cursor: pointer; color: #555; font-size: 14px; }
.text-danger { color: #ff4757; }
.user-info { font-size: 14px; color: #1a73e8; font-weight: bold; }

.view { display: none; flex: 1; padding: 20px; box-sizing: border-box; overflow-y: auto; }
.view.active { display: block; animation: fadeIn 0.3s ease; }

@keyframes fadeIn {
    from { opacity: 0; transform: translateY(10px); }
    to { opacity: 1; transform: translateY(0); }
}

.content-center { text-align: center; margin-top: 100px; }
.content-center h2 { color: #333; font-size: 28px; }
.content-center p { color: #666; line-height: 1.6; }

.form-box { margin-top: 10px; }
.form-box h2 { margin-bottom: 20px; text-align: center; color: #333; }

input {
    width: 100%; padding: 15px; margin-bottom: 15px;
    border: 1px solid #ddd; border-radius: 10px; box-sizing: border-box;
    font-size: 15px; background: #f8f9fa; transition: border 0.2s;
}
input:focus { outline: none; border-color: #1a73e8; background: white; }

.primary-btn {
    width: 100%; padding: 15px; border: none; border-radius: 10px;
    background: #1a73e8; color: white; font-size: 16px; font-weight: bold; cursor: pointer;
}
.primary-btn:hover { background: #1557b0; }

.google-btn {
    width: 100%; padding: 12px; border: 1px solid #ddd; border-radius: 10px;
    background: white; color: #333; font-size: 15px; font-weight: bold; cursor: pointer;
    display: flex; align-items: center; justify-content: center; gap: 10px;
    margin-bottom: 15px; transition: background 0.2s;
}
.google-btn:hover { background: #f8f9fa; }
.google-btn img { width: 20px; height: 20px; }

.divider { text-align: center; margin: 20px 0; position: relative; }
.divider::before { content: ""; position: absolute; left: 0; top: 50%; width: 100%; height: 1px; background: #ddd; z-index: 1; }
.divider span { background: white; padding: 0 10px; color: #888; font-size: 13px; position: relative; z-index: 2; }

.switch-text { text-align: center; margin-top: 20px; font-size: 14px; color: #666; }
.switch-text span { color: #1a73e8; font-weight: bold; cursor: pointer; }
.error-msg { color: #ff4757; font-size: 13px; text-align: center; margin-top: 15px; word-break: keep-all; }