:root {
    --primary-color: #4f46e5;
    --primary-hover: #4338ca;
    --bg-color: #f8fafc;
    --text-color: #1e293b;
    --card-bg: #ffffff;
    --border-color: #e2e8f0;
    --danger: #ef4444;
    --success: #22c55e;
    --shadow: 0 4px 6px -1px rgb(0 0 0 / 0.1), 0 2px 4px -2px rgb(0 0 0 / 0.1);
    --radius: 12px;
}

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

body {
    font-family: 'Inter', -apple-system, BlinkMacSystemFont, "Segoe UI", Roboto, Helvetica, Arial, sans-serif;
    background-color: var(--bg-color);
    color: var(--text-color);
    line-height: 1.5;
}

.container {
    max-width: 1000px;
    margin: 0 auto;
    padding: 0 1.5rem;
}

/* Header */
header {
    background-color: var(--card-bg);
    padding: 1.5rem 0;
    box-shadow: 0 1px 3px 0 rgb(0 0 0 / 0.1);
    margin-bottom: 2rem;
}

header .container {
    display: flex;
    justify-content: space-between;
    align-items: center;
}

h1 {
    font-size: 1.5rem;
    font-weight: 700;
}

/* Buttons */
.btn-primary {
    background-color: var(--primary-color);
    color: white;
    padding: 0.5rem 1rem;
    border: none;
    border-radius: var(--radius);
    font-weight: 600;
    cursor: pointer;
    transition: background-color 0.2s;
}

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

.btn-secondary {
    background-color: transparent;
    color: var(--text-color);
    padding: 0.5rem 1rem;
    border: 1px solid var(--border-color);
    border-radius: var(--radius);
    font-weight: 600;
    cursor: pointer;
}

.btn-close {
    background: none;
    border: none;
    font-size: 1.5rem;
    cursor: pointer;
    color: #64748b;
}

/* Events Grid */
.events-grid {
    display: grid;
    grid-template-columns: repeat(auto-fill, minmax(300px, 1fr));
    gap: 1.5rem;
}

.empty-state {
    grid-column: 1 / -1;
    text-align: center;
    padding: 4rem 2rem;
    background: var(--card-bg);
    border-radius: var(--radius);
    border: 2px dashed var(--border-color);
    color: #64748b;
}

/* Event Card */
.event-card {
    background: var(--card-bg);
    border-radius: var(--radius);
    padding: 1.5rem;
    box-shadow: var(--shadow);
    position: relative;
    display: flex;
    flex-direction: column;
    align-items: center;
    text-align: center;
}

.delete-event {
    position: absolute;
    top: 0.75rem;
    right: 0.75rem;
    background: #fee2e2;
    color: var(--danger);
    border: none;
    width: 28px;
    height: 28px;
    border-radius: 50%;
    cursor: pointer;
    display: flex;
    align-items: center;
    justify-content: center;
    font-weight: bold;
    opacity: 0;
    transition: opacity 0.2s;
}

.event-card:hover .delete-event {
    opacity: 1;
}

.event-title {
    font-size: 1.25rem;
    font-weight: 700;
    margin-bottom: 0.5rem;
}

.event-date-display {
    font-size: 0.875rem;
    color: #64748b;
    margin-bottom: 1.5rem;
}

/* Progress Ring */
.progress-ring-container {
    position: relative;
    width: 150px;
    height: 150px;
    margin-bottom: 1.5rem;
}

.progress-ring {
    transform: rotate(-90deg);
}

.progress-ring__circle {
    transition: stroke-dashoffset 0.35s;
    transform-origin: 50% 50%;
    stroke: var(--primary-color);
}

.progress-ring__background {
    stroke: var(--border-color);
}

.countdown-values {
    position: absolute;
    top: 50%;
    left: 50%;
    transform: translate(-50%, -50%);
    width: 100%;
}

.time-unit {
    display: flex;
    flex-direction: column;
    align-items: center;
}

.time-value {
    font-size: 1.5rem;
    font-weight: 700;
}

.time-label {
    font-size: 0.625rem;
    text-transform: uppercase;
    letter-spacing: 0.05em;
    color: #64748b;
}

.countdown-timer {
    display: grid;
    grid-template-columns: repeat(4, 1fr);
    width: 100%;
    gap: 0.5rem;
}

/* Modal */
.modal-overlay {
    position: fixed;
    top: 0;
    left: 0;
    width: 100%;
    height: 100%;
    background: rgba(0, 0, 0, 0.5);
    display: flex;
    align-items: center;
    justify-content: center;
    z-index: 1000;
    transition: opacity 0.3s ease;
}

.modal-overlay.hidden {
    display: none;
    opacity: 0;
}

.modal {
    background: white;
    padding: 2rem;
    border-radius: var(--radius);
    width: 90%;
    max-width: 450px;
    box-shadow: 0 20px 25px -5px rgb(0 0 0 / 0.1);
}

.modal-header {
    display: flex;
    justify-content: space-between;
    align-items: center;
    margin-bottom: 1.5rem;
}

.form-group {
    margin-bottom: 1.25rem;
}

.form-group label {
    display: block;
    font-size: 0.875rem;
    font-weight: 600;
    margin-bottom: 0.5rem;
}

.form-group input {
    width: 100%;
    padding: 0.625rem;
    border: 1px solid var(--border-color);
    border-radius: 8px;
    font-size: 1rem;
}

.form-actions {
    display: flex;
    justify-content: flex-end;
    gap: 0.75rem;
    margin-top: 2rem;
}

/* Animations */
@keyframes pulse {
    0% { transform: scale(1); }
    50% { transform: scale(1.05); }
    100% { transform: scale(1); }
}

.time-value.changing {
    animation: pulse 0.3s ease-out;
}

/* Finished State */
.event-card.finished {
    border: 2px solid var(--success);
}

/* Responsive */
@media (max-width: 640px) {
    .events-grid {
        grid-template-columns: 1fr;
    }
    
    header h1 {
        font-size: 1.25rem;
    }
}