/* Color Palette */
:root {
    --navy: #001f3f;
    --light-blue: #87ceeb;
    --light-blue-dark: #5fb9e0;
    --white: #ffffff;
    --light-gray: #f5f5f5;
    --medium-gray: #ddd;
    --dark-gray: #666;
    --success: #28a745;
    --danger: #dc3545;
    --warning: #ffc107;
    
    /* Theme variables */
    --bg-gradient-start: #fffacd;
    --bg-gradient-end: #f4d03f;
    --text-primary: #001f3f;
    --text-secondary: #ffffff;
    --card-bg: #ffffff;
    --input-bg: #ffffff;
    --input-border: #ddd;
}

/* Dark Mode */
body.dark-mode {
    --bg-gradient-start: #000814;
    --bg-gradient-end: #001f3f;
    --text-primary: #87ceeb;
    --text-secondary: #ffffff;
    --card-bg: #001a33;
    --input-bg: #002147;
    --input-border: #003d66;
}

/* Reset & Base Styles */
* {
    margin: 0;
    padding: 0;
    box-sizing: border-box;
}

body {
    font-family: 'Segoe UI', Tahoma, Geneva, Verdana, sans-serif;
    background: linear-gradient(135deg, var(--bg-gradient-start) 0%, var(--bg-gradient-end) 100%);
    min-height: 100vh;
    padding: 20px;
    color: var(--text-primary);
    transition: background 0.3s ease, color 0.3s ease;
}

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

/* Header */
header {
    text-align: center;
    color: var(--white);
    margin-bottom: 40px;
}

header h1 {
    font-size: 2.5rem;
    margin-bottom: 10px;
    text-shadow: 2px 2px 4px rgba(0, 0, 0, 0.3);
}

.subtitle-container {
    display: flex;
    align-items: center;
    justify-content: center;
    gap: 15px;
}

.subtitle {
    font-size: 1.1rem;
    opacity: 0.9;
}

.theme-toggle {
    background: var(--navy);
    border: 2px solid var(--navy);
    border-radius: 50%;
    width: 32px;
    height: 32px;
    display: flex;
    align-items: center;
    justify-content: center;
    cursor: pointer;
    transition: all 0.3s ease;
    font-size: 1rem;
}

.theme-toggle:hover {
    background: #003366;
    border-color: #003366;
    transform: scale(1.1) rotate(15deg);
}

/* Sections */
.add-event-section,
.events-section {
    background: var(--card-bg);
    border-radius: 12px;
    padding: 30px;
    margin-bottom: 30px;
    box-shadow: 0 4px 6px rgba(0, 0, 0, 0.1);
    transition: background 0.3s ease;
}

.add-event-section h2,
.events-section h2 {
    color: var(--text-primary);
    margin-bottom: 20px;
    font-size: 1.5rem;
}

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

/* Form Styles */
.form-group {
    margin-bottom: 20px;
}

.form-group label {
    display: block;
    margin-bottom: 8px;
    font-weight: 600;
    color: var(--text-primary);
}

.form-group input,
.form-group textarea {
    width: 100%;
    padding: 12px;
    border: 2px solid var(--input-border);
    border-radius: 8px;
    font-size: 1rem;
    background: var(--input-bg);
    color: var(--text-primary);
    transition: border-color 0.3s, background 0.3s;
}

.form-group input:focus,
.form-group textarea:focus {
    outline: none;
    border-color: var(--light-blue);
}

/* Buttons */
.btn {
    padding: 12px 24px;
    border: none;
    border-radius: 8px;
    font-size: 1rem;
    font-weight: 600;
    cursor: pointer;
    transition: all 0.3s;
    margin-right: 10px;
}

.btn-primary {
    background: var(--navy);
    color: var(--white);
}

.btn-primary:hover {
    background: #003366;
    transform: translateY(-2px);
    box-shadow: 0 4px 8px rgba(0, 0, 0, 0.2);
}

.btn-secondary {
    background: var(--medium-gray);
    color: var(--navy);
}

.btn-secondary:hover {
    background: var(--dark-gray);
    color: var(--white);
}

.btn-notification {
    background: var(--light-blue);
    color: var(--navy);
    padding: 10px 20px;
    font-size: 0.9rem;
}

.btn-notification:hover {
    background: var(--light-blue-dark);
}

.btn-notification.enabled {
    background: var(--success);
    color: var(--white);
}

/* Events Container */
.events-container {
    display: grid;
    grid-template-columns: repeat(auto-fill, minmax(300px, 1fr));
    gap: 20px;
}

.empty-state {
    grid-column: 1 / -1;
    text-align: center;
    color: var(--text-primary);
    opacity: 0.7;
    font-size: 1.1rem;
    padding: 40px;
}

/* Event Card */
.event-card {
    background: linear-gradient(135deg, var(--light-blue) 0%, var(--light-blue-dark) 100%);
    border-radius: 12px;
    padding: 20px;
    color: var(--white);
    position: relative;
    box-shadow: 0 4px 6px rgba(0, 0, 0, 0.1);
    transition: transform 0.3s;
}

.event-card:hover {
    transform: translateY(-5px);
    box-shadow: 0 6px 12px rgba(0, 0, 0, 0.15);
}

.event-card.expired {
    background: linear-gradient(135deg, var(--dark-gray) 0%, var(--medium-gray) 100%);
    opacity: 0.7;
}

/* Calendar Section */
.calendar-section {
    background: var(--card-bg);
}

.calendar-controls {
    display: flex;
    align-items: center;
    gap: 15px;
}

.current-month {
    font-size: 1.2rem;
    font-weight: 600;
    color: var(--text-primary);
    min-width: 200px;
    text-align: center;
}

.calendar-nav-btn {
    background: var(--navy);
    color: var(--white);
    border: none;
    border-radius: 6px;
    width: 36px;
    height: 36px;
    cursor: pointer;
    font-size: 1rem;
    display: flex;
    align-items: center;
    justify-content: center;
    transition: all 0.3s;
}

.calendar-nav-btn:hover {
    background: #003366;
    transform: scale(1.1);
}

.calendar-grid {
    margin-top: 20px;
}

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

.calendar-day-name {
    text-align: center;
    font-weight: 700;
    color: var(--text-primary);
    padding: 10px;
    font-size: 0.9rem;
}

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

.calendar-cell {
    min-height: 100px;
    border: 2px solid var(--input-border);
    border-radius: 8px;
    padding: 8px;
    background: var(--input-bg);
    position: relative;
    transition: all 0.3s;
}

.calendar-cell.empty {
    background: transparent;
    border: none;
}

.calendar-cell.today {
    border-color: var(--navy);
    background: rgba(135, 206, 235, 0.1);
}

.calendar-cell.past {
    opacity: 0.5;
}

.calendar-cell.has-events {
    background: rgba(135, 206, 235, 0.15);
}

.calendar-cell.has-events:hover {
    transform: translateY(-2px);
    box-shadow: 0 4px 8px rgba(0, 0, 0, 0.1);
}

.calendar-date {
    font-weight: 700;
    color: var(--text-primary);
    margin-bottom: 5px;
    font-size: 1rem;
}

.calendar-events {
    display: flex;
    flex-direction: column;
    gap: 4px;
    margin-top: 8px;
}

.calendar-event {
    background: linear-gradient(135deg, var(--light-blue) 0%, var(--light-blue-dark) 100%);
    color: var(--navy);
    padding: 4px 6px;
    border-radius: 4px;
    font-size: 0.75rem;
    font-weight: 600;
    overflow: hidden;
    text-overflow: ellipsis;
    white-space: nowrap;
    cursor: default;
}

/* Dark Mode Calendar */
body.dark-mode .calendar-nav-btn {
    background: var(--light-blue);
    color: var(--navy);
}

body.dark-mode .calendar-nav-btn:hover {
    background: var(--light-blue-dark);
}

body.dark-mode .calendar-cell.today {
    border-color: var(--light-blue);
    background: rgba(135, 206, 235, 0.2);
}

body.dark-mode .calendar-cell.has-events {
    background: rgba(135, 206, 235, 0.1);
}

.event-header {
    display: flex;
    justify-content: space-between;
    align-items: flex-start;
    margin-bottom: 15px;
}

.event-name {
    font-size: 1.3rem;
    font-weight: 700;
    margin-bottom: 5px;
    color: var(--navy);
}

.event-date {
    font-size: 0.9rem;
    opacity: 0.9;
    color: var(--navy);
}

.event-actions {
    display: flex;
    gap: 8px;
}

.icon-btn {
    background: rgba(255, 255, 255, 0.3);
    border: none;
    width: 32px;
    height: 32px;
    border-radius: 50%;
    cursor: pointer;
    display: flex;
    align-items: center;
    justify-content: center;
    transition: all 0.3s;
    font-size: 1rem;
}

.icon-btn:hover {
    background: rgba(255, 255, 255, 0.5);
    transform: scale(1.1);
}

.event-description {
    margin-bottom: 15px;
    font-size: 0.9rem;
    color: var(--navy);
    opacity: 0.9;
}

/* Countdown Display */
.countdown {
    display: grid;
    grid-template-columns: repeat(4, 1fr);
    gap: 10px;
    margin-top: 15px;
}

.countdown-item {
    background: rgba(0, 31, 63, 0.3);
    border-radius: 8px;
    padding: 12px 8px;
    text-align: center;
}

.countdown-value {
    display: block;
    font-size: 1.8rem;
    font-weight: 700;
    color: var(--white);
}

.countdown-label {
    display: block;
    font-size: 0.75rem;
    text-transform: uppercase;
    opacity: 0.8;
    margin-top: 4px;
}

.expired-message {
    text-align: center;
    padding: 15px;
    background: rgba(0, 0, 0, 0.2);
    border-radius: 8px;
    font-size: 1.1rem;
    font-weight: 600;
}

/* Dark Mode Adjustments */
body.dark-mode .btn-secondary {
    background: #003d66;
    color: var(--light-blue);
}

body.dark-mode .btn-secondary:hover {
    background: #005080;
}

body.dark-mode .icon-btn {
    background: rgba(135, 206, 235, 0.2);
}

body.dark-mode .icon-btn:hover {
    background: rgba(135, 206, 235, 0.3);
}

/* Responsive Design */
@media (max-width: 768px) {
    header h1 {
        font-size: 2rem;
    }
    
    .subtitle-container {
        flex-direction: column;
        gap: 10px;
    }
    
    .section-header {
        flex-direction: column;
        align-items: flex-start;
        gap: 15px;
    }
    
    .events-container {
        grid-template-columns: 1fr;
    }
    
    .countdown {
        gap: 8px;
    }
    
    .countdown-value {
        font-size: 1.5rem;
    }
    
    /* Calendar responsive */
    .calendar-controls {
        flex-direction: row;
        justify-content: center;
    }
    
    .calendar-cell {
        min-height: 80px;
        padding: 4px;
    }
    
    .calendar-date {
        font-size: 0.85rem;
    }
    
    .calendar-event {
        font-size: 0.65rem;
        padding: 3px 4px;
    }
    
    .calendar-day-name {
        font-size: 0.75rem;
        padding: 8px 4px;
    }
}