/* ===== CSS Variables & Design Tokens ===== */
:root {
    /* Colors */
    --primary-gradient: linear-gradient(135deg, #667eea 0%, #764ba2 100%);
    --bg-primary: #0f0f1a;
    --bg-secondary: #1a1a2e;
    --bg-card: rgba(30, 30, 50, 0.8);
    --bg-glass: rgba(255, 255, 255, 0.05);

    --text-primary: #ffffff;
    --text-secondary: rgba(255, 255, 255, 0.7);
    --text-muted: rgba(255, 255, 255, 0.5);

    --border-color: rgba(255, 255, 255, 0.1);
    --accent-color: #3b82f6;

    /* Activity Colors */
    --run-color: #22c55e;
    --ride-color: #3b82f6;
    --weight-color: #9ca3af;

    /* Spacing */
    --spacing-md: 1rem;
    --spacing-xl: 2rem;

    /* Border Radius */
    --radius-lg: 16px;

    /* Shadows */
    --shadow-lg: 0 8px 32px rgba(0, 0, 0, 0.4);
}

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

body {
    font-family: 'Inter', -apple-system, BlinkMacSystemFont, 'Segoe UI', Roboto, sans-serif;
    background: var(--bg-primary);
    color: var(--text-primary);
    min-height: 100vh;
    display: flex;
    justify-content: center;
    padding: 20px;
}

body::before {
    content: '';
    position: fixed;
    top: 0;
    left: 0;
    right: 0;
    bottom: 0;
    background: radial-gradient(circle at 20% 20%, rgba(102, 126, 234, 0.15) 0%, transparent 40%),
    radial-gradient(circle at 80% 80%, rgba(118, 75, 162, 0.15) 0%, transparent 40%),
    radial-gradient(circle at 50% 50%, rgba(240, 147, 251, 0.05) 0%, transparent 60%);
    pointer-events: none;
    z-index: 0;
}

.app-container {
    position: relative;
    z-index: 1;
    width: 100%;
    max-width: 1200px;
    background: var(--bg-card);
    border: 1px solid var(--border-color);
    border-radius: var(--radius-lg);
    box-shadow: var(--shadow-lg);
    padding: 32px;
    backdrop-filter: blur(20px);
}

header {
    display: flex;
    justify-content: space-between;
    align-items: center;
    margin-bottom: 32px;
    padding-bottom: 24px;
    border-bottom: 1px solid var(--border-color);
}

h1 {
    font-size: 24px;
    font-weight: 700;
    margin: 0;
    background: var(--primary-gradient);
    -webkit-background-clip: text;
    -webkit-text-fill-color: transparent;
    background-clip: text;
}

.controls {
    display: flex;
    align-items: center;
    gap: 24px;
}

.file-upload-btn {
    background: var(--bg-glass);
    border: 1px solid var(--border-color);
    color: var(--text-primary);
    padding: 10px 20px;
    border-radius: 6px;
    cursor: pointer;
    font-size: 14px;
    font-weight: 500;
    transition: all 0.2s;
    display: inline-flex;
    align-items: center;
}

.file-upload-btn:hover {
    background: rgba(255, 255, 255, 0.1);
    border-color: rgba(102, 126, 234, 0.5);
}

input[type="file"] {
    display: none;
}

.legend {
    display: flex;
    gap: 16px;
    font-size: 14px;
    color: var(--text-secondary);
}

.legend-item {
    display: flex;
    align-items: center;
    gap: 8px;
}

.dot {
    width: 12px;
    height: 12px;
    border-radius: 50%;
    display: inline-block;
}

.run-dot {
    background-color: var(--run-color);
}

.ride-dot {
    background-color: var(--ride-color);
}

.weight-dot {
    background-color: var(--weight-color);
}

/* Calendar Grid */
main {
    overflow-x: auto;
    -webkit-overflow-scrolling: touch;
}

.calendar-grid {
    display: grid;
    grid-template-columns: repeat(8, minmax(100px, 1fr));
    gap: 4px;
    min-width: 800px;
}

.week-row {
    display: contents;
}

.day-cell {
    min-width: 0;
    aspect-ratio: 1;
    background-color: rgba(255, 255, 255, 0.03);
    border: 1px solid var(--border-color);
    border-radius: 8px;
    padding: 24px 4px 4px 4px;
    position: relative;
    display: flex;
    flex-direction: column;
    align-items: center;
    justify-content: center;
    transition: all 0.2s;
    min-height: 100px;
}

.summary-cell {
    min-width: 0;
    aspect-ratio: auto;
    background-color: rgba(255, 255, 255, 0.05);
    border: 1px solid var(--border-color);
    border-radius: 8px;
    padding: 8px;
    display: flex;
    flex-direction: column;
    justify-content: center;
    font-size: 11px;
    color: var(--text-secondary);
    line-height: 1.4;
}

.day-cell:hover {
    background-color: rgba(255, 255, 255, 0.08);
    transform: translateY(-2px);
    box-shadow: 0 4px 12px rgba(0, 0, 0, 0.2);
    border-color: rgba(102, 126, 234, 0.3);
    z-index: 1;
}

.day-date {
    position: absolute;
    top: 6px;
    left: 8px;
    font-size: 12px;
    font-weight: 600;
    color: var(--text-secondary);
}

.day-cell.other-month .day-date {
    color: var(--text-muted);
    opacity: 0.5;
}

.activities-container {
    display: flex;
    flex-direction: column;
    align-items: center;
    justify-content: center;
    gap: 4px;
    width: 100%;
}

.activity-dot {
    border-radius: 50%;
    transition: transform 0.2s;
    display: flex;
    align-items: center;
    justify-content: center;
    color: white;
    font-size: 10px;
    font-weight: 500;
    text-align: center;
    line-height: 1;
    overflow: hidden;
    white-space: nowrap;
}

.activity-dot:hover {
    transform: scale(1.1);
}

/* Tooltip */
.tooltip {
    position: absolute;
    background-color: var(--bg-secondary);
    color: var(--text-primary);
    padding: 8px 12px;
    border-radius: 6px;
    border: 1px solid var(--border-color);
    font-size: 12px;
    pointer-events: none;
    z-index: 100;
    opacity: 0;
    transition: opacity 0.2s;
    white-space: pre-line;
    box-shadow: 0 4px 12px rgba(0, 0, 0, 0.3);
}

/* Year Control */
.year-control-wrapper {
    display: flex;
    align-items: center;
}

.year-select {
    appearance: none;
    background-color: var(--bg-glass);
    border: 1px solid var(--border-color);
    border-radius: 6px;
    padding: 8px 32px 8px 12px;
    font-family: inherit;
    font-size: 14px;
    color: var(--text-primary);
    cursor: pointer;
    background-image: url("data:image/svg+xml,%3Csvg xmlns='http://www.w3.org/2000/svg' fill='none' viewBox='0 0 24 24' stroke='white' stroke-width='2'%3E%3Cpath stroke-linecap='round' stroke-linejoin='round' d='M19 9l-7 7-7-7'/%3E%3C/svg%3E");
    background-repeat: no-repeat;
    background-position: right 8px center;
    background-size: 16px;
    transition: all 0.2s;
}

option {
    background-color: var(--bg-secondary);
    color: var(--text-primary);
}

.year-select:hover {
    border-color: rgba(102, 126, 234, 0.5);
    background-color: rgba(255, 255, 255, 0.1);
}

.year-select:focus {
    outline: none;
    border-color: #667eea;
    box-shadow: 0 0 0 3px rgba(102, 126, 234, 0.2);
}

footer {
    text-align: center;
    margin-top: 2rem;
    font-size: 0.875rem;
    color: var(--text-muted);
}

/* ===== Authentication UI ===== */

/* User Menu */
.user-menu {
    display: flex;
    align-items: center;
    gap: 12px;
}

.user-info {
    display: flex;
    align-items: center;
    gap: 8px;
    padding: 8px 12px;
    background: var(--bg-glass);
    border: 1px solid var(--border-color);
    border-radius: 8px;
}

.user-platform {
    font-size: 16px;
}

.user-name {
    font-size: 14px;
    font-weight: 500;
    color: var(--text-primary);
}

.user-login-btn,
.user-logout-btn,
.user-sync-btn {
    padding: 8px 16px;
    border-radius: 8px;
    font-size: 14px;
    font-weight: 500;
    cursor: pointer;
    transition: all 0.2s;
    border: none;
}

.user-login-btn {
    background: var(--primary-gradient);
    color: var(--text-primary);
    box-shadow: 0 4px 12px rgba(102, 126, 234, 0.3);
}

.user-login-btn:hover {
    transform: translateY(-1px);
    box-shadow: 0 6px 16px rgba(102, 126, 234, 0.4);
}

.user-logout-btn {
    background: var(--bg-glass);
    color: var(--text-secondary);
    border: 1px solid var(--border-color);
}

.user-logout-btn:hover {
    background: rgba(255, 255, 255, 0.1);
    color: var(--text-primary);
}

.user-sync-btn {
    background: rgba(34, 197, 94, 0.12);
    color: var(--text-primary);
    border: 1px solid rgba(34, 197, 94, 0.35);
}

.user-sync-btn:hover {
    background: rgba(34, 197, 94, 0.2);
    color: var(--text-primary);
}

/* Auth Modal Overlay */
.auth-modal-overlay {
    position: fixed;
    top: 0;
    left: 0;
    right: 0;
    bottom: 0;
    background: rgba(0, 0, 0, 0.7);
    backdrop-filter: blur(4px);
    display: flex;
    align-items: center;
    justify-content: center;
    z-index: 1000;
    opacity: 0;
    visibility: hidden;
    transition: all 0.3s ease;
}

.auth-modal-overlay.open {
    opacity: 1;
    visibility: visible;
}

/* Auth Modal */
.auth-modal {
    background: var(--bg-secondary);
    border: 1px solid var(--border-color);
    border-radius: var(--radius-lg);
    padding: 32px;
    width: 90%;
    max-width: 420px;
    transform: scale(0.95) translateY(10px);
    transition: transform 0.3s cubic-bezier(0.34, 1.56, 0.64, 1);
    box-shadow: var(--shadow-lg);
}

.auth-modal-overlay.open .auth-modal {
    transform: scale(1) translateY(0);
}

.auth-modal-header {
    display: flex;
    justify-content: space-between;
    align-items: center;
    margin-bottom: 24px;
}

.auth-modal-header h2 {
    font-size: 1.5rem;
    font-weight: 700;
    background: var(--primary-gradient);
    -webkit-background-clip: text;
    -webkit-text-fill-color: transparent;
    background-clip: text;
}

.auth-close-btn {
    background: none;
    border: none;
    color: var(--text-secondary);
    font-size: 24px;
    cursor: pointer;
    padding: 4px;
    line-height: 1;
    transition: color 0.2s;
}

.auth-close-btn:hover {
    color: var(--text-primary);
}

.auth-subtitle {
    color: var(--text-secondary);
    font-size: 14px;
    margin-bottom: 20px;
    text-align: center;
}

/* Auth Steps */
.auth-step {
    animation: fadeIn 0.3s ease;
}

.auth-step.hidden {
    display: none;
}

/* Platform Buttons */
.platform-buttons {
    display: flex;
    flex-direction: column;
    gap: 12px;
}

.platform-btn {
    display: flex;
    align-items: center;
    gap: 16px;
    width: 100%;
    padding: 16px 20px;
    background: var(--bg-glass);
    border: 1px solid var(--border-color);
    border-radius: 12px;
    cursor: pointer;
    transition: all 0.2s;
    text-align: left;
}

.platform-btn:hover:not(.disabled) {
    background: rgba(255, 255, 255, 0.1);
    border-color: rgba(102, 126, 234, 0.5);
    transform: translateX(4px);
}

.platform-btn.disabled {
    opacity: 0.5;
    cursor: not-allowed;
}

.platform-icon {
    font-size: 24px;
}

.platform-name {
    flex: 1;
    font-size: 16px;
    font-weight: 600;
    color: var(--text-primary);
}

.platform-badge {
    font-size: 11px;
    padding: 4px 8px;
    background: rgba(102, 126, 234, 0.2);
    color: #667eea;
    border-radius: 4px;
    font-weight: 500;
}

/* Back Button */
.auth-back-btn {
    background: none;
    border: none;
    color: var(--text-secondary);
    font-size: 14px;
    cursor: pointer;
    padding: 0;
    margin-bottom: 16px;
    transition: color 0.2s;
}

.auth-back-btn:hover {
    color: var(--text-primary);
}

/* Auth Form */
.auth-form-group {
    margin-bottom: 16px;
}

.auth-form-group label {
    display: block;
    font-size: 13px;
    font-weight: 500;
    color: var(--text-secondary);
    margin-bottom: 6px;
}

.auth-form-group input {
    width: 100%;
    padding: 12px 16px;
    background: var(--bg-glass);
    border: 1px solid var(--border-color);
    border-radius: 8px;
    color: var(--text-primary);
    font-size: 15px;
    font-family: inherit;
    transition: all 0.2s;
}

.auth-form-group input::placeholder {
    color: var(--text-muted);
}

.auth-form-group input:focus {
    outline: none;
    border-color: rgba(102, 126, 234, 0.5);
    box-shadow: 0 0 0 3px rgba(102, 126, 234, 0.2);
}

/* Auth Error */
.auth-error {
    background: rgba(239, 68, 68, 0.1);
    border: 1px solid rgba(239, 68, 68, 0.3);
    color: #f87171;
    padding: 12px 16px;
    border-radius: 8px;
    font-size: 14px;
    margin-bottom: 16px;
}

.auth-error.hidden {
    display: none;
}

/* Submit Button */
.auth-submit-btn {
    width: 100%;
    padding: 14px 24px;
    background: var(--primary-gradient);
    border: none;
    border-radius: 10px;
    color: var(--text-primary);
    font-size: 16px;
    font-weight: 600;
    cursor: pointer;
    transition: all 0.2s;
    box-shadow: 0 4px 16px rgba(102, 126, 234, 0.4);
}

.auth-submit-btn:hover:not(:disabled) {
    transform: translateY(-2px);
    box-shadow: 0 6px 20px rgba(102, 126, 234, 0.5);
}

.auth-submit-btn:disabled {
    opacity: 0.7;
    cursor: not-allowed;
}

.auth-submit-btn .btn-loading.hidden,
.auth-submit-btn .btn-text.hidden {
    display: none;
}

/* Auth Note */
.auth-note {
    margin-top: 16px;
    font-size: 12px;
    color: var(--text-muted);
    text-align: center;
    line-height: 1.5;
}

/* Login Prompt */
.login-prompt {
    grid-column: 1 / -1;
    text-align: center;
    padding: 60px 40px;
    max-width: 500px;
    margin: 0 auto;
}

.login-prompt-icon {
    font-size: 48px;
    margin-bottom: 20px;
}

.login-prompt h2 {
    font-size: 1.5rem;
    font-weight: 600;
    color: var(--text-primary);
    margin-bottom: 12px;
}

.login-prompt p {
    color: var(--text-secondary);
    font-size: 14px;
    margin-bottom: 24px;
    line-height: 1.6;
}

.login-prompt-btn {
    display: inline-flex;
    align-items: center;
    gap: 8px;
    padding: 14px 28px;
    background: var(--primary-gradient);
    border: none;
    border-radius: 10px;
    color: var(--text-primary);
    font-size: 16px;
    font-weight: 600;
    cursor: pointer;
    transition: all 0.2s;
    box-shadow: 0 4px 16px rgba(102, 126, 234, 0.4);
}

.login-prompt-btn:hover {
    transform: translateY(-2px);
    box-shadow: 0 6px 20px rgba(102, 126, 234, 0.5);
}

/* Animations */
@keyframes fadeIn {
    from {
        opacity: 0;
    }
    to {
        opacity: 1;
    }
}

/* Activity Status Message */
.activity-status {
    background: linear-gradient(135deg, rgba(34, 197, 94, 0.15) 0%, rgba(59, 130, 246, 0.15) 100%);
    border: 1px solid rgba(34, 197, 94, 0.3);
    border-radius: 10px;
    padding: 12px 20px;
    margin-bottom: 20px;
    color: var(--text-secondary);
    font-size: 14px;
    animation: fadeIn 0.3s ease-out;
}

.activity-status .status-main {
    display: flex;
    flex-wrap: wrap;
    align-items: center;
    gap: 10px;
}

.activity-status .status-icon {
    color: #22c55e;
    font-weight: bold;
}

.activity-status strong {
    color: var(--text-primary);
}

.activity-status .status-date {
    color: var(--text-muted);
    font-size: 12px;
}