:root {
    --bg-color: #121212;
    --surface: #1e1e1e;
    --primary: #03A9F4;
    --text: #e0e0e0;
    --border: #333;
    --danger: #f44336;
    --success: #4CAF50;
    --warning: #FF9800;
}

body {
    background-color: var(--bg-color);
    color: var(--text);
    font-family: 'Segoe UI', Tahoma, Geneva, Verdana, sans-serif;
    margin: 0;
    padding: 0;
}

.login-container { display: flex; flex-direction: column; align-items: center; justify-content: center; height: 100vh; text-align: center; }
.app-container { max-width: 1200px; margin: 0 auto; padding: 10px; }

/* FROZEN HEADER */
header {
    display: flex; justify-content: space-between; align-items: center; background: var(--surface); padding: 15px 20px;
    border-radius: 8px; margin-bottom: 20px; position: sticky; top: 5px; z-index: 1000; box-shadow: 0 4px 10px rgba(0,0,0,0.5);
}

.user-info { display: flex; align-items: center; gap: 15px; }
.user-info img { width: 45px; height: 45px; border-radius: 50%; }

.header-actions { display: flex; align-items: center; gap: 20px; }
.notification { font-size: 24px; cursor: pointer; position: relative; }
.badge {
    position: absolute; top: -5px; right: -8px; background: var(--danger); color: white; font-size: 12px; font-weight: bold;
    padding: 2px 6px; border-radius: 50%;
}
.badge-warning { background: var(--warning); color: #000; }

.admin-nav { display: flex; gap: 10px; margin-bottom: 20px; }
.admin-nav button {
    background: var(--surface); color: var(--text); border: 1px solid var(--border); padding: 12px 20px; cursor: pointer; border-radius: 5px; flex: 1;
}
.admin-nav button:hover, .admin-nav button.active-tab { background: #333; border-color: var(--primary); }

.tab-content { display: none; }
.tab-content.active { display: block; }

input, textarea, select {
    width: 100%; padding: 12px; margin-bottom: 15px; background: var(--surface); border: 1px solid var(--border);
    color: var(--text); border-radius: 5px; box-sizing: border-box;
}

.btn { padding: 10px 15px; border: none; border-radius: 5px; cursor: pointer; color: #fff; font-weight: bold;}
.btn-primary { background: var(--primary); }
.btn-danger { background: var(--danger); }
.btn-success { background: var(--success); }
.btn-warning { background: var(--warning); color: #000; }

/* Calendar Headers & Controls */
.calendar-header { display: flex; justify-content: space-between; align-items: center; margin-bottom: 20px; flex-wrap: wrap; gap: 15px; }
.year-selector { display: flex; align-items: center; gap: 15px; background: #222; padding: 5px 15px; border-radius: 8px; border: 1px solid var(--border); }
.year-selector button { background: none; border: none; color: var(--primary); font-size: 20px; cursor: pointer; padding: 0 10px; transition: 0.2s;}
.year-selector button:hover { transform: scale(1.2); color: #fff; }
.year-selector span { font-size: 20px; font-weight: bold; }

/* Calendar Styles */
#calendar-grid { display: grid; grid-template-columns: repeat(auto-fit, minmax(250px, 1fr)); gap: 15px; }

/* scroll-margin ensures the frozen header doesn't cover the month when auto-scrolling */
.month-card { background: #222; padding: 15px; border-radius: 8px; text-align: center; scroll-margin-top: 110px;}
.days-grid { display: grid; grid-template-columns: repeat(7, 1fr); gap: 4px; margin-top: 15px; }

.day { 
    background: #333; color: #eee; border-radius: 6px; cursor: pointer; font-size: 15px; 
    user-select: none; display: flex; justify-content: center; align-items: center; height: 40px; box-sizing: border-box; transition: 0.2s;
}
.day:hover { background: #444; }

/* Past Dates Faded Out */
.day.past-date { opacity: 0.35; }

.day.has-appointment { background-color: var(--primary) !important; color: #ffffff !important; border: none !important; }
.day.has-appointment:hover { background-color: #0288D1 !important; }

/* Modal */
.modal { display: none; position: fixed; top: 0; left: 0; width: 100%; height: 100%; background: rgba(0,0,0,0.8); z-index: 2000; overflow-y: auto; }
.modal-content { background: var(--surface); margin: 10% auto; padding: 20px; width: 90%; max-width: 600px; border-radius: 8px; position: relative; }
.small-modal { max-width: 350px; text-align: center; margin-top: 20%;}
.close { position: absolute; right: 15px; top: 10px; cursor: pointer; font-size: 28px; color: #aaa; }
.close:hover { color: #fff; }
.popup-modal { z-index: 3000; }

/* Cards & Actions */
.appt-card { background: #252525; padding: 15px; border-radius: 8px; margin-bottom: 15px; border-left: 4px solid var(--primary); }
.appt-card p { margin: 5px 0; font-size: 14px; color: #ccc;}
.action-buttons { display: flex; gap: 8px; margin-top: 15px; flex-wrap: wrap; }
.action-buttons button { flex: 1; padding: 8px; font-size: 13px; }

.report-row { display: flex; justify-content: space-between; padding: 12px; border-bottom: 1px solid var(--border); }

/* MOBILE RESPONSIVENESS */
@media (max-width: 768px) {
    header { flex-direction: column; top: 0; border-radius: 0; padding: 10px; gap: 15px; }
    .header-actions { width: 100%; justify-content: space-between; }
    .admin-nav { flex-wrap: wrap; gap: 5px; }
    .admin-nav button { flex: 1 1 45%; padding: 10px; font-size: 13px; }
    .days-grid { gap: 4px; }
    .day { font-size: 14px; height: 40px; }
    .action-buttons button { flex: 1 1 45%; }
}