.countdown-container {
    max-width: 900px;
    margin: 1rem auto;
    padding: 0 1rem;
}

.countdown-header {
    text-align: center;
    margin-bottom: 2rem;
}

.countdown-header h1 {
    color: var(--text-color);
    margin-bottom: 1rem;
}

.countdown-header .description {
    color: #666;
    font-size: 1.05rem;
}

.planner-section {
    background: white;
    padding: 2rem;
    border-radius: 12px;
    box-shadow: 0 3px 12px rgba(15, 23, 42, 0.08);
    margin-bottom: 2rem;
}

.input-grid {
    display: grid;
    grid-template-columns: repeat(2, minmax(0, 1fr));
    gap: 1.5rem;
}

.input-grid .full-width {
    grid-column: 1 / -1;
}

.input-group {
    display: flex;
    flex-direction: column;
    gap: 0.5rem;
}

.input-group label {
    font-weight: 600;
    color: var(--text-color);
}

.input-group input,
.input-group select,
.input-group textarea {
    padding: 0.85rem 1rem;
    border: 1px solid #d1d5db;
    border-radius: 8px;
    font-size: 1rem;
    background-color: white;
    transition: border-color 0.2s ease, box-shadow 0.2s ease;
}

.input-group textarea {
    resize: vertical;
    min-height: 120px;
}

.input-group input:focus,
.input-group select:focus,
.input-group textarea:focus {
    outline: none;
    border-color: var(--primary-color);
    box-shadow: 0 0 0 3px rgba(0, 123, 255, 0.1);
}

.action-bar {
    display: flex;
    flex-wrap: wrap;
    gap: 1rem;
    justify-content: center;
    margin-top: 2rem;
}

.action-bar .btn {
    min-width: 180px;
    padding: 0.85rem 1.5rem;
    font-size: 1rem;
    border-radius: 8px;
    border: none;
    cursor: pointer;
    transition: transform 0.2s ease, box-shadow 0.2s ease;
}

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

.btn.secondary {
    background: #f3f4f6;
    color: #111827;
}

.btn:hover {
    transform: translateY(-1px);
    box-shadow: 0 8px 20px rgba(15, 23, 42, 0.12);
}

.results-section {
    display: none;
    background: white;
    padding: 2rem;
    border-radius: 12px;
    box-shadow: 0 3px 12px rgba(15, 23, 42, 0.08);
    margin-bottom: 2.5rem;
}

.countdown-status {
    text-align: center;
    margin-bottom: 2rem;
}

.countdown-status span {
    display: block;
    font-size: 1rem;
    color: #6b7280;
}

.countdown-status .highlight {
    font-size: 2.5rem;
    font-weight: 700;
    color: var(--primary-color);
    margin-top: 0.5rem;
}

.result-grid {
    display: grid;
    grid-template-columns: repeat(auto-fit, minmax(180px, 1fr));
    gap: 1.5rem;
}

.result-card {
    background: #f9fafb;
    border-radius: 12px;
    padding: 1.5rem;
    text-align: center;
    box-shadow: inset 0 0 0 1px rgba(229, 231, 235, 0.8);
}

.result-card h3 {
    font-size: 1rem;
    color: #4b5563;
    margin-bottom: 0.75rem;
    text-transform: uppercase;
    letter-spacing: 0.08em;
}

.result-card .value {
    font-size: 1.8rem;
    font-weight: 700;
    color: #111827;
}

.event-overview {
    margin-top: 2rem;
    background: #f3f4f6;
    border-left: 4px solid var(--primary-color);
    padding: 1.25rem;
    border-radius: 10px;
    color: #1f2937;
}

.event-overview strong {
    display: block;
    margin-bottom: 0.5rem;
    font-size: 1.05rem;
}

.timeline-section {
    margin-bottom: 2.5rem;
}

.timeline-header {
    display: flex;
    align-items: center;
    gap: 0.75rem;
    margin-bottom: 1rem;
}

.timeline-header i {
    color: var(--primary-color);
    font-size: 1.4rem;
}

.timeline-list {
    list-style: none;
    padding: 0;
    margin: 0;
    display: grid;
    gap: 1rem;
}

.timeline-list li {
    background: white;
    border-radius: 12px;
    padding: 1.5rem;
    box-shadow: 0 1px 4px rgba(15, 23, 42, 0.08);
}

.timeline-list h3 {
    font-size: 1.15rem;
    color: var(--primary-color);
    margin-bottom: 0.65rem;
}

.timeline-list p {
    color: #4b5563;
    line-height: 1.65;
}

.instructions-container {
    background: white;
    border-radius: 12px;
    padding: 2rem;
    box-shadow: 0 3px 12px rgba(15, 23, 42, 0.08);
    margin-bottom: 3rem;
}

.instructions-container h2 {
    font-size: 1.8rem;
    color: var(--text-color);
    margin-bottom: 2rem;
}

.instructions-container h3 {
    font-size: 1.3rem;
    margin-top: 2rem;
    margin-bottom: 1rem;
    color: var(--primary-color);
}

.instructions-container h4 {
    font-size: 1.1rem;
    margin-bottom: 0.6rem;
    color: #1f2937;
}

.instructions-container p {
    color: #4b5563;
    line-height: 1.8;
    margin-bottom: 1.2rem;
}

.instructions-container ul {
    margin: 0 0 1.5rem 1.5rem;
    color: #4b5563;
    line-height: 1.7;
}

.instructions-container li {
    margin-bottom: 0.6rem;
}

.feature,
.example {
    background: #f9fafb;
    border-radius: 12px;
    padding: 1.5rem;
    margin-bottom: 1.2rem;
    box-shadow: inset 0 0 0 1px rgba(229, 231, 235, 0.8);
}

.feature p,
.example p {
    margin-bottom: 0.75rem;
}

.message {
    position: fixed;
    top: 1.5rem;
    right: 1.5rem;
    padding: 1rem 1.25rem;
    border-radius: 10px;
    color: white;
    background: #10b981;
    box-shadow: 0 10px 25px rgba(16, 185, 129, 0.25);
    z-index: 9999;
    animation: slideIn 0.3s ease;
}

.message.error {
    background: #ef4444;
    box-shadow: 0 10px 25px rgba(239, 68, 68, 0.25);
}

@keyframes slideIn {
    from {
        transform: translateX(30%);
        opacity: 0;
    }
    to {
        transform: translateX(0);
        opacity: 1;
    }
}

@media (max-width: 768px) {
    .countdown-container {
        padding: 0 0.75rem;
    }

    .planner-section {
        padding: 1.5rem;
    }

    .input-grid {
        grid-template-columns: 1fr;
    }

    .action-bar {
        flex-direction: column;
    }

    .action-bar .btn {
        width: 100%;
    }

    .result-grid {
        grid-template-columns: repeat(auto-fit, minmax(150px, 1fr));
    }
}

@media (prefers-color-scheme: dark) {
    .planner-section,
    .results-section,
    .timeline-list li {
        background: #1f2937;
        box-shadow: 0 3px 12px rgba(0, 0, 0, 0.4);
    }

    .result-card {
        background: #111827;
        box-shadow: inset 0 0 0 1px rgba(55, 65, 81, 0.9);
    }

    .result-card .value,
    .timeline-list p,
    .event-overview {
        color: #f9fafb;
    }

    .input-group input,
    .input-group select,
    .input-group textarea {
        background: #111827;
        color: #f9fafb;
        border-color: #374151;
    }

    .input-group input:focus,
    .input-group select:focus,
    .input-group textarea:focus {
        border-color: #60a5fa;
        box-shadow: 0 0 0 3px rgba(96, 165, 250, 0.25);
    }

    .btn.secondary {
        background: #374151;
        color: #f9fafb;
    }

    .event-overview {
        background: #111827;
    }

    .instructions-container {
        background: #1f2937;
    }

    .feature,
    .example {
        background: #111827;
        box-shadow: inset 0 0 0 1px rgba(75, 85, 99, 0.85);
    }

    .instructions-container h4 {
        color: #e5e7eb;
    }
}