:root {
    --bg-color: #f8fafc;
    --primary-color: #3b82f6;
    --primary-hover: #2563eb;
    --text-main: #1e293b;
    --text-muted: #64748b;
    --card-bg: #ffffff;
    --border-color: #e2e8f0;
    --success: #10b981;
    --warning: #f59e0b;
    --error: #ef4444;
    --shadow-sm: 0 1px 2px 0 rgb(0 0 0 / 0.05);
    --shadow-md: 0 4px 6px -1px rgb(0 0 0 / 0.1);
}

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

body {
    font-family: 'Inter', system-ui, -apple-system, sans-serif;
    background-color: var(--bg-color);
    color: var(--text-main);
    line-height: 1.5;
    -webkit-font-smoothing: antialiased;
}

/* 清新、簡潔、留白感 */
#app {
    min-height: 100vh;
}

.initial-loading {
    display: flex;
    flex-direction: column;
    align-items: center;
    justify-content: center;
    height: 100vh;
}

/* 登入視圖 */
.login-container {
    max-width: 400px;
    margin: 10vh auto;
    padding: 2rem;
    text-align: center;
}

.login-container h1 {
    font-size: 1.5rem;
    font-weight: 600;
    margin-bottom: 0.5rem;
    letter-spacing: -0.025em;
}

.login-container p {
    color: var(--text-muted);
    margin-bottom: 2rem;
}

.login-cont.badge-draft {
    background: #f1f5f9;
    color: var(--text-muted);
}

.empty-state,
.error {
    padding: 3rem;
    text-align: center;
    color: var(--text-muted);
    font-size: 0.875rem;
    background: #f8fafc;
    border-radius: 0.5rem;
    border: 1px dashed var(--border-color);
    margin: 1rem 0;
}

.error {
    color: var(--error);
    background: #fef2f2;
    border-color: #fca5a5;
    border-style: solid;
}

.login-box {
    background: var(--card-bg);
    padding: 2rem;
    border-radius: 1rem;
    box-shadow: var(--shadow-md);
    border: 1px solid var(--border-color);
}

.input-group {
    position: relative;
    margin-bottom: 1rem;
    display: flex;
    align-items: center;
}

.input-group i {
    position: absolute;
    left: 1rem;
    width: 18px;
    height: 18px;
    color: var(--text-muted);
}

.input-group input {
    width: 100%;
    padding: 0.75rem 1rem 0.75rem 3rem;
    border: 1px solid var(--border-color);
    border-radius: 0.5rem;
    font-size: 0.875rem;
    transition: all 0.2s;
}

.input-group input:focus {
    outline: none;
    border-color: var(--primary-color);
    box-shadow: 0 0 0 3px rgba(59, 130, 246, 0.1);
}

.btn-primary {
    width: 100%;
    padding: 0.75rem;
    background-color: var(--primary-color);
    color: white;
    border: none;
    border-radius: 0.5rem;
    font-weight: 500;
    cursor: pointer;
    transition: background 0.2s;
}

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

.test-logins {
    margin-top: 2rem;
    padding-top: 1rem;
    border-top: 1px solid var(--border-color);
}

.test-logins p {
    font-size: 0.75rem;
    margin-bottom: 0.5rem;
}

.test-logins button {
    padding: 0.25rem 0.5rem;
    font-size: 0.75rem;
    margin: 0.25rem;
    background: #f1f5f9;
    border: 1px solid var(--border-color);
    border-radius: 0.25rem;
    cursor: pointer;
}

/* Toast */
.toast {
    position: fixed;
    bottom: 2rem;
    right: 2rem;
    padding: 0.75rem 1.5rem;
    background: white;
    border-radius: 0.5rem;
    box-shadow: var(--shadow-md);
    transform: translateY(100%);
    opacity: 0;
    transition: all 0.3s cubic-bezier(0.4, 0, 0.2, 1);
    z-index: 1000;
}

.toast.show {
    transform: translateY(0);
    opacity: 1;
}

.toast-success {
    border-left: 4px solid var(--success);
}

.toast-error {
    border-left: 4px solid var(--error);
}

/* Layout */
.container {
    max-width: 1000px;
    margin: 2rem auto;
    padding: 0 1rem;
}

/* Tabs: 上圓下方、負邊界融合 */
.project-tabs {
    display: flex;
    overflow-x: auto;
    margin-bottom: -1px;
    /* 負邊界與內容區塊融合 */
    padding-left: 1rem;
}

.tab {
    padding: 0.75rem 1.5rem;
    background: #e2e8f0;
    border: 1px solid var(--border-color);
    border-bottom: none;
    border-radius: 12px 12px 0 0;
    margin-right: 0.25rem;
    font-size: 0.875rem;
    color: var(--text-muted);
    cursor: pointer;
    transition: all 0.2s;
}

.tab.active {
    background: var(--card-bg);
    color: var(--primary-color);
    font-weight: 600;
    border-color: var(--border-color);
    box-shadow: 0 -2px 10px rgba(0, 0, 0, 0.02);
}

.project-details-container {
    background: var(--card-bg);
    border: 1px solid var(--border-color);
    border-radius: 1rem;
    padding: 2rem;
    min-height: 400px;
    box-shadow: var(--shadow-sm);
}

/* Progress Track */
.progress-bar-container {
    margin: 3rem 0;
    position: relative;
}

.progress-line {
    position: absolute;
    top: 50%;
    left: 0;
    right: 0;
    height: 4px;
    background: #f1f5f9;
    transform: translateY(-50%);
    border-radius: 2px;
}

.progress-fill {
    height: 100%;
    background: var(--primary-color);
    transition: width 0.8s cubic-bezier(0.65, 0, 0.35, 1);
    border-radius: 2px;
}

.steps-container {
    display: flex;
    justify-content: space-between;
    position: relative;
    z-index: 1;
}

.step-item {
    display: flex;
    flex-direction: column;
    align-items: center;
    width: 60px;
}

.step-dot {
    width: 12px;
    height: 12px;
    background: white;
    border: 2px solid #cbd5e1;
    border-radius: 50%;
    transition: all 0.3s;
}

.step-item.active .step-dot {
    background: var(--primary-color);
    border-color: var(--primary-color);
    box-shadow: 0 0 0 4px rgba(59, 130, 246, 0.2);
}

.step-label {
    margin-top: 0.75rem;
    font-size: 0.7rem;
    color: var(--text-muted);
    white-space: nowrap;
}

/* Accordion */
.accordion-item {
    margin-bottom: 0.5rem;
    background: var(--card-bg);
    border: 1px solid var(--border-color);
    border-radius: 0.5rem;
    overflow: hidden;
}

.accordion-header {
    padding: 1rem;
    display: flex;
    align-items: center;
    cursor: pointer;
    gap: 0.75rem;
}

.accordion-header.level-1 {
    background: #f8fafc;
}

.accordion-header.level-2 {
    padding-left: 2.5rem;
    border-top: 1px solid var(--border-color);
}

.accordion-header i {
    width: 18px;
    color: var(--text-muted);
}

.accordion-header .arrow {
    transition: transform 0.3s;
}

.accordion-content {
    display: none;
    background: white;
}

.accordion-content.show {
    display: block;
}

.detail-view {
    padding: 1.5rem 3rem;
    border-top: 1px dashed var(--border-color);
}

/* Document Grid */
.document-grid {
    display: grid;
    grid-template-columns: repeat(auto-fill, minmax(180px, 1fr));
    gap: 1.5rem;
    margin-top: 1.5rem;
}

.doc-item {
    padding: 1rem;
    background: #fdfdfd;
    border: 1px dashed var(--border-color);
    border-radius: 0.75rem;
    text-align: center;
    cursor: pointer;
    transition: all 0.2s;
}

.doc-item:hover {
    border-color: var(--primary-color);
    background: #f0f7ff;
}

/* Badges */
.badge {
    font-size: 0.65rem;
    padding: 0.2rem 0.5rem;
    background: #f1f5f9;
    border-radius: 1rem;
    margin-left: auto;
}

.btn-delete {
    background: #fee2e2;
    color: var(--error);
    border: 1px solid #fecaca;
    padding: 0.25rem 0.75rem;
    font-size: 0.75rem;
    border-radius: 0.25rem;
    cursor: pointer;
}

/* RWD 文字旋轉 */
@media (max-width: 768px) {
    .step-label {
        transform: rotate(-45deg);
        margin-top: 1.5rem;
        margin-left: 1rem;
    }

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